This research reports on an efficient shoot proliferation and callus regeneration system for bamboo. Young, semi-lignified branches with one lateral bud from Drepanostachyum luodianense (Yi et R. S. Wang) Keng f. were used as explants. Disinfection with 0.1% HgCl2 for 8 min was the optimum treatment and the best medium for bud initiation was Murashige and Skoog (MS) medium containing 3.0 mg L−1 6-benzyladenine (BA). Multiple shoots were induced from nodal shoot segments on MS medium containing 5.0 mg L−1 BA, 0.5 mg L−1 kinetin (Kin), and 1.0 mg L−1 naphthaleneacetic acid (NAA). The highest frequency of callus formation (65.6%) was on MS medium containing 4.0 mg L−1 2,4-dichlorophenoxyacetic acid (2, 4-D), 0.5 mg L−1 NAA, and 0.1 mg L−1 thidiazuron (TDZ). The optimum medium for callus proliferation was MS medium with 4 mg L−1 2,4-D, 0.5 mg L−1 TDZ and 0.5 mg L−1 NAA, and the optimum hormone combination was 4 mg L−1 BA + 0.5 mg L−1 NAA for callus redifferentiation (up to 85.6%). A 100% rooting was achieved on MS medium supplemented with 2.0 mg L−1 NAA and 0.5 mg L−1 3-indole butyric acid (IBA). Rooted plantlets were acclimatized in a greenhouse in humus soil + perlite (1:1) substrate. These micropropagated callus induction and regeneration systems for bamboo will be useful for genetic engineering and multiplication.
This study investigates the effects of cold-acclimation in conferring chilling tolerance in seedlings of the mulberry (Morus alba) variety ‘Qiuyu’. Changes in photosynthesis and antioxidant enzymes in chilling acclimatized (CA), and non-acclimatized (NA) seedlings were recorded during chilling stress (3 °C) and a recovery period (25 °C) each for 3 days. The results showed that CA plants had higher net photosynthetic rates (P n), stomatal conductance (G s), and maximum photochemical efficiency of photosystem II (F v /F m) in response to chilling stress compared to NA. The seedlings maintained the same trends during the recovery stage. The responses of QA reduction degree and prime electronic transfer rates (F o) were lower in acclimatized than in non-acclimatized seedlings. Low-temperature acclimation and chilling stress also caused an increase in leaf proline and soluble sugar contents. Leaf malondialdehyde levels were significantly lower while ascorbate peroxidase (APX) activity was significantly higher in acclimatized seedlings, suggesting that elevated osmolytes and APX confer resistance to chilling temperatures. In this study on the response of mulberry seedlings to chilling stress, we also looked at the recovery process. The response to chilling determines whether mulberry leaves can survive under cold temperatures, while the recovery process determines whether photosynthesis can recover as soon as possible to avoid any secondary damage.
Bark beetles Tomicus yunnanensis and T. minor are two important pests of Pinus yunnanensis and can cause massive death of pine trees. In this study, we examined several traits related to photosynthesis in P. yunnanensis and their relationship with antibiotic defense responses after joint attack by the two bark beetles at the shoot and the trunk stages. When shoots were attacked by the beetles, the abundance of chlorophylls, carotenoids, and the rates of net photosynthesis (Pn) and transpiration (E) decreased in needles, while the levels of superoxide dismutase and malondialdehyde remained unchanged in both needles and phloem. The activity of peroxidases also remained unchanged in needles, but increased in phloem. The activity of catalases increased in both needles and phloem. When trunks were attacked by the bark beetles, chlorophyll abundance, Pn, E, and antioxidative enzyme activities all declined, and the declines were more pronounced than in the attacked shoots. A decrease in protein concentrations was also observed in needles and phloem from the attacked pines. Attack on shoots by the bark beetles suppressed host defense and provided a favorable environment for larval growth and development, resulting in long-term decline of pine growth potential. The results suggest that attacks on trunks by beetles caused more severe damage to host trees than attacks on shoots.
The reproductive biology of Cornus capitata was studied in detail from June 2014 to October 2015 in Tehri Garhwal, Uttarakhand, western Himalaya, India and elucidated floral morphology, confirming autogamy, geitonogamy, and xenogamy. A new inflorescence ball formed each year with developing fruits that were initiated the previous year; thus reproduction is a continuous cycle. The total pollen production within a tree ranged between 4.0 × 107 and 9.3 × 107. Anthesis peaked between 08:00 and 10:00. There was significant effect of micro-environmental condition on anthesis (F = 243.8, p = 3.01). A significant positive relationship between the number of lateral shoots and total inflorescence showed that the inflorescence production in C. capitate depends largely on the number of lateral shoots. Time and concentration of various solutions significantly affected pollen germination (time: F = 5.39, p = 0.002; concentration: F = 1.40, p = 0.234). Anthophora bees and thrips were observed as the main pollinators. There was a significant difference in seed set between natural and obligate self-pollination (t = 11.84, p = 1.99). Significant effect was also observed on fruit size (t = 8.88, p = 2.09) between open and shaded conditions. SEM micrographs of pollen grains showed that the shape of dehydrated pollen grains differed greatly due to variations in the rate of dehydration among pollen grains within the anther. Seed germination was observed only in quality seed derived from open pollination, supporting xenogamy in C. capitata. Findings of the present study will be of immense value in formulating effective conservation measures for the species in wild habitats.
Bamboos are used extensively for a variety of purposes, and many new species have been introduced to the northwestern Himalaya. However, their potential as a fodder species has not been investigated. Six bamboo species, namely Dendrocalamus hamiltonii Gamble, Dendrocalamus asper (Schult. and Schult.f.) Backer ex K. Heyne, Melocanna baccifera (Roxb.) Kurz, Phyllostachys aurea Riviére and C. Riviére, Phyllostachys bambusoides Sieb and Zucc. and Phyllostachys pubescens (Pradelle) Mazel ex J. Houz. were evaluated for their nutritional value, relative palatability and best lopping time. Dry matter (DM), ether extract (EE), and crude fibre varied from (37.0–67.7)%, (4.7–7.6), and (22.1–37.9)%, respectively. Values of crude protein ranged from (12.2–17.1)%, total ash (TA) from (11.8–21.5)%, acid insoluble ash (AIA) from (0.3–0.5)%, nitrogen free extract from (31.1–40.8)%, carbohydrates from (57.0–69.0)%, organic matter (OM) from (78.5–88.2)%, calcium from (1.7–2.3)%, phosphorus from (0.4–0.8)%, potassium from, (0.9–1.6)%, magnesium from (0.5–0.9)%, sodium from (603.7–1072.7) × 10−6 and vitamin A from (21.1–30.5) × 10−2 mg/g, respectively. D. hamiltonii had maximum values for DM, EE, TA and AIA. OM and vitamin A were highest in M. baccifera. CF and carbohydrates were maximized in P. aurea and CP in P. pubescens. All the values obtained for different bamboo species were less than maximum tolerable concentration of common feed resources of the region thereby indicating their suitability for nutrition and palatability. The contents of anti-nutritional factors, namely hydrocyanic acid and tannin ranged from (33.8–61.7) × 10−2 mg/g and (0.7–1.9)%, respectively. P. pubescens was the best species from a palatability point of view and has maximum crude protein content (17.2%), Ca (2.3%) and lowest tannin content (0.7%). The relative palatability of introduced bamboo species followed trend: P. pubescens (97.6%) > D. hamiltonii (92.5%) > P. bambusoides (81.2%) > D. asper (76.9%) > M. baccifera (75.9%) > P. aurea (73.4%). The optimum months for lopping these species for green leaves are November and December, as the nutritional value declines sharply thereafter.
Spatial variation in tree-regeneration density is attributed to the specialization of tree species to light availability for germination and growth. Light availability, in turn, varies across the gap-understorey mosaic. Canopy gaps provide an important habitat for the regeneration of tree species that would otherwise be suppressed in the understory. In subtropical forests, there is still a knowledge-gap relating to how canopy disturbances influence tree-regeneration patterns at local scale, and if they disproportionately favor regeneration of certain species. We aim to analyze whether canopy gaps promote tree regeneration, and tree species are specialized to gaps or understory for germination and growth. We sampled vegetation in 128 plots (0.01 ha), equally distributed in gaps and below canopy, in two subtropical Shorea robusta Gaertn. (Sal) forests in Nepal, recording the number of tree seedlings and saplings in each plot. We compared the regeneration density of seedlings and saplings separately between gaps and the understorey. The mean densities of seedlings and saplings were higher in the gaps at both sites; although there was no difference in the seedling density of the majority of the species between the habitats. No species were confined to either gap or understorey at the seedling stage. We conclude that gaps are not critical for the germination of tree species in Sal forests but these are an important habitat for enabling seedlings to survive into saplings. The classification of trees into regeneration guilds mainly based on germination does not apply to the majority of tree species in subtropical Sal forests. Our results reaffirm that gap creation promotes tree regeneration by favouring seedling survival and growth and can influence forest management for conservation, as well as for plantations.
The hollow cylindrical culm is one of the most remarkable morphological characters of most bamboo species. In relation to its hollow structure, there are two different attributes of the culm volume in bamboo: the apparent culm volume (v a: the total culm volume including the hollow portion) and the woody culm volume (v w: the volume of the woody walls of the culm). The ratio of v w to v a is defined as the reduction factor for culm volume (f v). The quantity f v is useful to quantify the biomass resources of bamboo culms as well as to evaluate the carbon stock of bamboo forests. However, the direct measurement of f v requires destructive sampling, which consumes time and labor. Hence, an alternative method for obtaining f v is desired. In this study, we examined f v in five species of the genus Phyllostachys and proposed alternative methods to estimate f v. Our data showed that f v varied by species, some of which exhibited a dependency of f v on culm sizes. These findings indicate that the intraspecific and interspecific variation in f v should be considered carefully when converting v a into v w by f v. Based on our results, we propose here six approaches for predicting f v and we discuss their advantages and disadvantages. Our results are intended to facilitate evaluation of the carbon sequestration capacity of bamboo forests and the commercial utilization of bamboo culms.
One of the basic parameters in forest management planning is detailed knowledge of growing stock, information collected by forest inventory. Sampling methods must be accurate, inexpensive, and be easy to implement in the field. This study presents a new sampling method called branching transect for use in the Iranian Zagros forests and similar forests. Features of the new method include greater accuracy, easy implementation in nature, simplicity of statistical calculations, and low cost. In this method, transect is used, which includes some sub-transects (side branches). The length of the main transect, side branches, number of trees measured in each side branch, and the number of sub-branches in this method are changeable based on homogeneity, heterogeneity, and density of a forest. In this study, based on the density and heterogeneity of the forest area studied, 20-m transects with four and eight side branches were used. Sampling plots (Transects) in four inventory networks (100 m × 100 m, 100 m × 150 m, 150 m × 150 m and 100 m × 200 m) were implemented in the GIS environment. The results of this sampling method were compared to the results of total inventory (100% count) in terms of accuracy, precision (t-test), and inventory error percentage. Branching transect results were statistially similar to total inventory counts in all cases. The results show that this method of estimating density and canopy per hectare can be used in Zagros forests and similar forests.
The fertiliser industry faces a continuing challenge to improve the efficiency of their products, particularly of nitrogenous fertilisers, and to minimise adverse impacts. Therefore, a new slow release fertilizer, urea-impregnated woodchips from tropical plant biomass (oil palm frond and rubberwood), was developed. The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry. When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h, release was slow and steady, although the release rate was lower in distilled water than in the soil solution.
Larix principis-rupprechtii Mayr is a dominant species in coniferous forests of North China. However, early selection of L. principis-rupprechtii for growth traits is poorly characterised. To explore the optimal selection age for this species, heights (HT) and diameters at breast (DBH) of 40 half-sib families were measured at ages 3, 12, 22, and 28 years in a progeny test population established in the town of Kangjiahui, Shanxi Province. Age trends in heritability, age–age genetic correlations, and early selection efficiency for height and DBH were analysed. The individual heritability of these growth traits varied over time, and maximized at different ages (0.55 at age 12 for HT and 0.48 at age 28 for DBH). The age–age genetic correlations were always positive, and the majority were high (0.790–0.953) between the juvenile and mature ages for HT and DBH. For the same pairs of measurements, HT demonstrated higher age–age genetic correlations than DBH, and both age–age genetic correlation data sets were described well by the linear relationship with the logarithm of the age ratio (r2 > 0.90). The regression slope for DBH was lower than that for HT. Based on the early selection efficiency estimates, the optimal selection age could be as early as age 6 for DBH and 8–9 years for HT. The results of this study provide information that can be used to assist early selection practices in L. principis-rupprechtii improvement programs in Shanxi Province.
Forests account for 80% of the total carbon exchange between the atmosphere and terrestrial ecosystems. Thus, to better manage our responses to global warming, it is important to monitor and assess forest aboveground carbon and forest aboveground biomass (FAGB). Different levels of detail are needed to estimate FAGB at local, regional and national scales. Multi-scale remote sensing analysis from high, medium and coarse spatial resolution data, along with field sampling, is one approach often used. However, the methods developed are still time consuming, expensive, and inconvenient for systematic monitoring, especially for developing countries, as they require vast numbers of field samples for upscaling. Here, we recommend a convenient two-scale approach to estimate FAGB that was tested in our study sites. The study was conducted in the Chitwan district of Nepal using GeoEye-1 (0.5 m), Landsat (30 m) and Google Earth very high resolution (GEVHR) Quickbird (0.65 m) images. For the local scale (Kayerkhola watershed), tree crowns of the area were delineated by the object-based image analysis technique on GeoEye images. An overall accuracy of 83% was obtained in the delineation of tree canopy cover (TCC) per plot. A TCC vs. FAGB model was developed based on the TCC estimations from GeoEye and FAGB measurements from field sample plots. A coefficient of determination (R 2) of 0.76 was obtained in the modelling, and a value of 0.83 was obtained in the validation of the model. To upscale FAGB to the entire district, open source GEVHR images were used as virtual field plots. We delineated their TCC values and then calculated FAGB based on a TCC versus FAGB model. Using the multivariate adaptive regression splines machine learning algorithm, we developed a model from the relationship between the FAGB of GEVHR virtual plots with predictor parameters from Landsat 8 bands and vegetation indices. The model was then used to extrapolate FAGB to the entire district. This approach considerably reduced the need for field data and commercial very high resolution imagery while achieving two-scale forest information and FAGB estimates at high resolution (30 m) and accuracy (R 2 = 0.76 and 0.7) with minimal error (RMSE = 64 and 38 tons ha−1) at local and regional scales. This methodology is a promising technique for cost-effective FAGB and carbon estimations and can be replicated with limited resources and time. The method is especially applicable for developing countries that have low budgets for carbon estimations, and it is also applicable to the Reducing Emissions from Deforestation and Forest Degradation (REDD +) monitoring reporting and verification processes.
The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant. The model of West, Brown and Enquist (WBE model) considers that a 3/4 scaling exponent of metabolic rate versus total mass to be optimal for each plant and has been confirmed numerous times. Although leaf area is a better proxy of the metabolic rate than leaf mass, few studies have focused on the scaling exponent of leaf area versus total mass and even fewer have discussed the diversification of this scaling exponent across different conditions. Here, I analyzed the scaling exponent of leaf area versus total mass of sample plots across world plants. I found that as the plant grows, it allocates fewer resources to photosynthetic tissues than expected by the WBE model. The results also empirically show that this scaling exponent varies significantly for different plant leaf habit, taxonomic class and geographic region. Therefore, leaf strategy in response to environmental pressure and constraint clearly plays a significant role.
Biodiversity has become an issue of global attention because of growing awareness of its importance and its rapid depletion worldwide. Diversity of tree species in relation to environmental and disturbance gradients was examined in three managed forests. Trees were randomly sampled in a survey of 75 circular plots (radius = 13 m) with 5 subplots (radius = 1 m). Generalized linear model analysis was used with a Poisson distribution log link function to understand the effects of variables (organic matter, organic carbon, nitrogen, potassium, pH, elevation and disturbance) on tree species richness. Canonical correspondence analysis was used to explore ecological relationships among plots. Our result found that the stand characteristics was an important influencing factor in the three forests. Our result showed that the variables had a highly positive influence on tree species richness in the three forests. In ordination, the selected variables governed the richness of tree species. Our study can help identify the most important factors that drive tree species richness in the three managed forests in Bangladesh and in similar ecosystems and inform forest management decisions for conservation according to ecological importance.
This study assesses the effects of human disturbance on: (1) floristic composition, diversity, and plant community types; and, (2) the regeneration potential of woody species in the Debrelibanos Monastery forest patch in the North Showa zone of Oromia National Regional State, Ethiopia. Fifty sample quadrats were placed on parallel transect lines along altitudes in the forest using a systematic sampling design. Quadrats of 1 m2, 100 m2 and 400 m2 were used for recording herbaceous/seedling, sapling and tree species, respectively, with symptoms of different human disturbance effects. One hundred and thirteen species belonging to 52 families were recorded in the forest patch. The results show 459.5 stems ha−1 of tree/shrub species present. Four community types, namely Juniperus procera–Acacia lahai, Carissa spinarum–Acacia abyssinica, Olea europaea subsp. cuspidata–Euphorbia abyssinica and Ficus sur–Allophylus abyssinicus were identified. The overall Shannon–Wiener diversity index was 3.3. The regeneration patterns of some species were poor. Slope, altitude and human activities had significant effects on vegetation patterns and imply that current management practices are not satisfactory to sustain the forest. Unless improved management interventions are made, the sustainability of forest services will be at stake.
Marginal water-use efficiency plays a critical role in plant carbon–water coupling relationships. We investigated the ecosystem marginal water-use efficiency (λ) of a tropical seasonal evergreen forest to (1) determine the general pattern of λ across time, (2) compare different models for calculating λ, and (3) address how λ varies with soil water content during different seasons. There was a U-shaped diurnal pattern in λ, which was higher in the early morning and late afternoon. At other times of the day, λ was lower and remained constant. Ecosystem λ was higher in the wet season than in the dry season. All three models successfully captured the diurnal and seasonal patterns of λ but differed in the calculated absolute values. The idea that λ is constant on a subdaily scale was partly supported by our study, while a constant λ was only true when data from the early morning and late afternoon were not included. The λ increases with soil water content on a seasonal scale, possibly because early morning λ remained low in dry conditions when the soil water content was low.
In 2014, a 40-ha undisturbed plot was established in the Beijing Songshan Nature Reserve. The spatial distribution and spatial associations of five dominant tree species of different height classes were examined using spatial point pattern analysis and the effects of these species on local community diversity assemblages were examined using the ISAR method. The dominant species were characterized by an aggregated distribution at spatial scales of 0–50 m. At smaller spatial scales, trees in larger height classes had significant positive and negative effects on the diversity of the lower height classes. However, at larger spatial scales this effect was diminished. At small scales (0–10 m), accumulator species had positive effects on species diversity, maintained an over-representative proportion of diversity in their proximity, and supported the ecological niche theory. At the larger scale (10–50 m), neutral species were dominant and had positive effects on species diversity, though repeller species, which had negative effects on species diversity, also contributed to diversity. Neutral and accumulator species together determined local species diversity, but the relative importance of the two was closely related to spatial scale. A combination of the ecological niche theory and neutral processes together determines species coexistence and biodiversity of an undisturbed pine forest.
Turkey, containing three of the world’s biodiversity hotspots, is a hub for genetic biodiversity. However, the vegetation cover has drastically changed in recent decades as a result of substantial transformations in land-use practices. A map of the potential natural vegetation can be used to represent the biodiversity of a country, and therefore a reference to effectively develop conservation strategies. The multinomial logistic regression is used to simulate the probability of different biomes occurring in the country using elevation, climatological data and natural vegetation data. A correlation test was applied to the climatological data to determine which predictors influence vegetation the most. These were temperature, precipitation, relative humidity and cloudiness. The Ordinary Kriging method was employed to transform the data into the format for the multinomial logistic regression model. The model showed that temperature was the most influencing factor with respect to Turkey’s vegetation and distribution follows a similar distribution as the various macroclimates. Broadleaf forests are mostly found in the Black Sea region, which is also the wettest region of the country. The Marmara region is the only other region where there are broadleaf forests. Mixed forests and shrublands are mostly located in Central Anatolia due to the region’s low humidity which favours herbaceous flora. Coniferous forests were dominant in the Aegean and Mediterranean regions, attributed to high temperatures.
Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures, function realization, and community succession. However, little is known about how abiotic and biotic drivers affect the diversity of understory species in cold temperate coniferous forests in the semiarid climate region of North China. We hypothesized that (1) topographic factors are important environmental factors affecting the distribution and variation of understory strata, and (2) different understory strata respond differently to environmental factors; shrubs may be significantly affected by the overstory stratum, and herbs may be more affected by surface soil conditions. To test these hypotheses, we used the boosted regression tree method to analyze abiotic and biotic environmental factors that influence understory species diversity, using data from 280 subplots across 56 sites in cold temperate coniferous forests of North China. Elevation and slope aspect were the dominant and indirect abiotic drivers affecting understory species diversity, and individual tree size inequality (DBH variation) was the dominant biotic driver of understory species diversity; soil water content was the main edaphic factors affecting herb layers. Elevation, slope aspect, and DBH variation accounted for 36.4, 14.5, and 12.1%, respectively, of shrub stratum diversity. Shrub diversity decreased with elevation within the range of altitude of this study, but increased with DBH variation; shrub diversity was highest on north-oriented slopes. The strongest factor affecting herb stratum species diversity was slope aspect, accounting for 25.9% of the diversity, followed by elevation (15.7%), slope (12.2%), and soil water content (10.3%). The highest herb diversity was found on southeast-oriented slopes and the lowest on northeast-oriented slopes; herb diversity decreased with elevation and soil water content, but increased with slope. The results of the study provide a reference for scientific management and biodiversity protection in cold temperate coniferous forests of North China.
Land use changes are a direct consequence of interactions between humans and nature. Analysing the spatial and temporal changes in habitat quality brought about by land use change can provide a scientific basis for ecological protection and land planning. Based on the analysis of land use change from 1990 to 2010 in Northeast China, we used the InVEST (integrated valuation of ecosystem services and trade-offs) module to evaluate habitat quality based on watershed subdivision. The results show that: (1) the main land use changes from 1990 to 2010 were the transition from grasslands and forest lands to agricultural lands, which led to a decrease in connectivity of landscape and an increase in fragmentation; (2) areas of high habitat quality were distributed north of the Greater Khingan Mountains, the region of the Lesser Khingan Mountains and east of the Changbai Mountains, while the central plain had low habitat quality; (3) agricultural lands had the largest effect on habitat degradation among all habitat threats. During these 2 decades, the contribution of agricultural lands to habitat degradation were 43.4% in 1990, 44.6% in 2000 and 43.9% in 2010; and, (4) at a landscape scale, patch density and splitting index present noticeable negative correlations with habitat quality index. Habitat quality was significantly affected by landscape fragmentation and decreased connectivity.
A decomposition experiment of Populus purdomii litter, a commonly used afforestation species in the Qinling Mountains, China, was conducted. Water extracts of five conifer litters were used to treat P. purdomii litter and its soil. The P. purdomii litter was incubated at room temperature (20–25 °C) and constant soil moisture for 6 months. During the decomposition period, the dynamics of litter mass and nutrient contents were detected to investigate the impacts of plant secondary metabolites. The results indicate that litter extracts of Pinus tabuliformis, Platycladus orientalis, Pinus armandii and Larix principis-rupprechtii significantly inhibited the overall nutrient release of P. purdomii litter, while the last three types of litter extracts simultaneously inhibited its decomposition. Conversely, the litter extracts of Picea asperata significantly accelerated the overall nutrient release of P. purdomii. Generally, most of the conifer species, whose litter released terpenoids, phenolics, steroids, and aliphatic acids, will inhibit the decomposition and/or nutrient release from P. purdomii litter. Their negative effects on the decomposers and soil enzymatic activities indicates that planting diversity should be lower when mixed planted with P. purdomii.
To find the quantitative trait loci associated with wood density in teak (Tectona grandis L.f.), 21 co-dominant markers including 13 site specific recombinase and 8 EST-based co-dominant markers designed from lignin biosynthesis genes were applied to 174 teak plus tree clones at the National Germplasm Bank, Chandrapur, India. The germplasm bank exhibited 10.6% coefficient of variation for wood densities with 84.5 ± 31.3 genetic polymorphism (%). The highly panmictic set of genotypes (FST = 0.035 ± 0.004) harbored 96.47 ± 0.40 genetic variability (%). The average allelic frequency of the 21 co-dominant markers was 0.65 ± 0.11 with 12.9% pairs of loci in significant LD (p < 0.05, R 2 values > 0.1), confirming their suitability for a strong marker-trait association study. The marker CCoAMT-1 was significantly (p < 0.01) associated with wood density showing stability by both GLM and MLM models and explained 4.3% of the phenotypic effect. The marker from the EST representing CCoAMT can be further developed for gene-assisted selection of elite genotypes of teak with greater wood density. Therefore, we believe that the report will help accelerate the genetic improvement and advance the breeding program of the species.
The VirE2-interaction protein 1 (VIP1) serves as a regulator of mitogen-activated protein kinase 3 (MPK3)-mediated stress gene modulation under biotic stress, which in turn activates the MPK3 pathway in Arabidopsis. The mode of action of the VIP1 protein in Populus in response to biotic stress remains unknown. In this study, we cloned the full-length cDNA of the PtVIP1 gene from Populus trichocarpa (accession number of GenBank: KY793105). The VIP1 protein harboured a conserved bZIP (basic leucine zipper) domain located in the C-terminus. The VIP1 subcellular localization assay indicated that the VIP1 protein was present in the cytoplasm and nucleus under normal conditions, and that an increase in the amount of the protein in the nucleus occurred after treatment with flg22, the elicitor-active epitope of flagellin which triggers the innate immune response in plants. Transgenic Populus plants overexpressing VIP1 genes (PtVIP1 of Populus; or AtVIP1 of Arabidopsis, as positive control) were generated to investigate the role of VIP1 in vivo. The expression of poplar pathogenesis-related protein 1 (PR1) genes was up-regulated in transgenic- PtVIP1 or AtVIP1 poplar plants. The transgenic poplar plants overexpressing PtVIP1 or AtVIP1 also showed enhanced resistance to Brenneria salicis infection. These results suggest that the VIP1 protein accumulates in the nucleus in response to biotic stress, and that the pathogen resistance of transgenic VIP1 poplar may be associated with the induced expression of PR1 genes in response to pathogen challenge.
The transcription factor BplMYB46 has been identified as a regulator of abiotic stress responses and promoter of secondary wall deposition in Betula platyphylla. To investigate the downstream targets of BplMYB46, the expression profiles of genes in stems from BplMYB46-overexpressing (OE) and BplMYB46-silencing (SE) plants were studied. In OE stems, 952 genes were upregulated, and 1469 were downregulated in comparison to SE stems. In a KEGG pathway enrichment analysis of differentially expressed genes (DEGs), 1387 differentially expressed genes were annotated for 117 metabolic pathways. DEGs were abundant for metabolic pathway, secondary metabolite biosynthesis, plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis. DEGs were implicated lignin or cellulose biosynthesis, cell wall modification, xylem development, disease resistance, stress responses, and anthocyanin biosynthesis. These results suggested that BplMYB46 regulates cell wall development and stress resistance by affecting the expression of these genes. Our study further elucidates the mechanism by which BplMYB46 mediates abiotic stress responses and secondary cell wall biosynthesis in birch.
Blooming date is an important trait in fruit tree species. Although several quantitative trait loci confirming blooming date were identified in Prunus spp., the molecular mechanism underlying it remains unclear. Arising from this, the transcriptomes of normal blooming and late-blooming Siberian apricot (P. sibirica L.) flower buds were analyzed using RNA-seq technology. A total of 68,855 unigenes were de novo assembled, among which 1204 were differentially expressed between normal and late blooming. Gene ontology enrichment analysis revealed that biological processes were enriched with metabolic processes. The catalytic-related gene transcripts between the two types of blooming were significantly changed in the molecular function. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 156 genes were successfully annotated and 75 pathways enriched. Genes for gibberellin biosynthesis were up-regulated in normal blooming, whereas abscisic acid degradation-related genes were also up-regulated in normal blooming. Moreover, circadian rhythms related genes including EARLY FLOWERING 4, LATE ELONGATED HYPOCOTYL and CIRCANDIAN CLOCK ASSOCIATED1 were all up-regulated in normal blooming, indicating that circadian rhythms have a very important role in controlling blooming date. Furthermore, zinc finger protein CONSTANS-LIKE 12 was blasted onto the quantitative trait loci region on linkage group 4 in peach. However, changes in the abundance of key flowering genes such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1, FLOWERING LOCU T, LEAFY and FLOWERING LOCUS C were not significantly different, indicating that further investigation should explore the function of these genes on blooming date. The outcomes of this study will provide a valuable platform for further research on the molecular mechanism of blooming date in Prunus.
This study identifies endogenous inhibitors of germination associated with seed dormancy in Sapium sebiferum, Chinese tallow. Seed extracts were separated into five distinct fractions (petroleum ether, ether, ethyl acetate, methanol, and aqueous) and tested for their effect on germination of cabbage seeds. There were no significant differences in germination percentages and germination index (GI) between the solvents and the control. The five fractions differentially reduced germination percentage and GI values of cabbage seeds. According to the GI results, the greatest inhibition was with the ether fraction followed by methanol, ethyl acetate, petroleum ether, and aqueous fractions. Gas chromatography–mass spectrometry identified the constituents of the four organic fractions. Compared with the mass spectrum of the National Institute of Standards and Technology library, a compound was confirmed, provided it was more than 85% similar. Analysis of ether extracts identified four compounds: butylated hydroxytoluene (BHT; 19.7%), 1,2-benzenediol (4.1%), p-hydroxycinnamic acid, ethyl ester (2.8%), and n-hexadecanoic acid (1.4%). Fourteen, 20, and 9 compounds were identified in methanol, ethyl acetate, and petroleum ether extracts, respectively. The IC50 of BHT (the concentration at which BHT inhibits radicle growth by 50%) was 54.8 mg/L, indicating that the presence of BHT might be the primary cause of dormancy in S. sebiferum seeds.
Distinctness, uniformity and stability (DUS) Test Guidelines for new varieties of Viburnum L. were developed according to the principles and requirements of the International Union for the Protection of New Varieties of Plants (UPOV) and China. The development processes, including selection and determination of testing characteristics, determination of expression states of characteristics, selection of example varieties, determination of the order of characteristics, and assessment of distinctness, uniformity and stability, are described in this paper. There were 54 testing characteristics: 24 qualitative characteristics (QL), 15 quantitative characteristics (QN), 15 pseudo-qualitative characteristics (PQ) and 34 example varieties in the DUS Test Guidelines. Among the 54 testing characteristics, 20 were asterisked and 34 were non-asterisked. Seven were selected for variety groupings and 18 were adopted in the Technical Questionnaire. The development of these DUS Test Guidelines will be useful for the application and protection of new Viburnum varieties. The Guidelines will provide technical support for DUS testing of Viburnum and serve as a reference for the development of new varieties in other countries.
Dendroremediation, a novel strategy for cleaning up contaminants from the environment by using special woody plant species and microbes, is a popular phytoremediation approach. It is a cost-effective and environmentally friendly method that is being increasingly adopted. Poplar species (Populus L.) have been suggested for use in remediation because of their characteristics of high biomass production, fast growth, and potential for removing pollutants. Our environment is often contaminated by toxic substances produced by human activities, and remediation of contamination is therefore a global issue. Atrazine is one of the most widely used herbicides in China. In the present study, ‘I-69/55’ poplar (P. deltoides cv. ‘I-69/55’) and hybrid poplar (Populus deltoides × nigra, DN34) grown in pots were assayed for their ability to remediate atrazine-contaminated soils. The degradation dynamics of atrazine were assessed with a high-performance liquid chromatography system using materials from a greenhouse with different rhizosphere environments. We studied the dynamic variation in microbes and microbial biomass carbon to elucidate the rhizosphere effects and mechanism of remediation of atrazine-contaminated soil by poplar. Our four treatments included a control with uncontaminated soil without a tree, atrazine pollution without a tree, atrazine pollution with ‘I-69/55’ poplar, and atrazine pollution with hybrid poplar. Hybrid poplar showed potential for remediation of atrazine-contaminated soil, and the degradation of atrazine in the rhizosphere was faster than that in non-rhizosphere soil. Atrazine significantly inhibited bacteria growth in non-rhizosphere soil. The high concentration of bacteria in the hybrid poplar rhizosphere might be key to atrazine degradation. Trends of change among fungi and actinomyces did not correspond to trends in atrazine degradation throughout the trial period. Further research is needed to predict the effects of atrazine on cultivable microorganisms in various soils. Atrazine had significant inhibitory effects on microbial biomass carbon in non-rhizosphere soil, and the rhizosphere environment of poplars enhanced the recovery of microbial biomass carbon. The potential for hybrid poplar as a dendroremediation material needs further study.
Because potassium (K) is a rock-derived essential element that can be depleted in highly-weathered tropical soils, K availability may limit some portion of soil microbial activity in tropical forest ecosystems. In this paper we tested if K limits microbial activity in the condition of sufficient labile C supply. An incubation experiment was performed using surface soil samples (0–10 cm depth) obtained from four permanent ecological research plots in a natural sub-tropical forest in southern China. Soil samples were taken in September 2016. Heterotrophic soil respiration rates and microbial biomass were measured after the addition of glucose (both D and L) with and without K (potassium chloride). We did not observe any effects of K addition on soil microbial respiration, suggesting that K does not limit the microbial activity in the condition of sufficient labile C supply. The lack of microbial response to added K can be attributed to the high mobility of K in forest ecosystems, which may have provided sufficient K to microbes in our soil samples (already provided at the beginning of the incubation). However, at the present stage, we cannot conclude that K is not a limiting factor of soil microbial activity in other tropical forest ecosystems because of the heterogeneity of tropical forest ecosystems and few observations. The hypothesis needs to be tested in larger numbers of tropical forests.
Phototoxic treatments of pathogenic bacteria and fungi of trees induce oxidative damage that is preferable to toxic chemical treatment. Here, we used green methods to synthesize Chlorin e6 from chlorophyll a, which was extracted from crude silkworm excrement using concentrated (strong) alkali hydrolysis and acidification. The photosensitive bactericidal activities of the new chlorin were tested in vitro, and possible mechanisms of action are discussed. The results showed that Chlorin e6 can be light-activated to have bactericidal activity against Escherichia coli, Bacillus subtilis and Fusarium oxysporum, but it had little bactericidal effect in the dark. This kind of chlorin compounds has great potential as a natural phototoxic antimicrobial compound to control harmful bacteria on the leaves in forestry systems.
Sudden oak death (SOD) is one of the most rapid and destructive forest pathogens, which has caused the death of many host plants in Europe and America. There are currently no cases in China where there are more host plants and a more suitable climate for this pathogen to survive. Therefore, it is vital to discern the potential suitable habitat, quantify the risk levels, and monitor the potential high-risk areas. In this study, we modelled the potential invasion range and risk level of this pathogen at present and in future scenarios in China, using the least correlated components of all the environmental factors based on the Genetic Algorithm for Ruleset Production niche model and GIS analysis. The results indicate that most areas in China are free from a potential SOD risk, and the majority of potential occurrence areas are concentrated in Southern China (Yunnan, Sichuan, Guizhou, Chongqing, Hunan, Fujian). The area of high and extremely high risk in 2050 (RCP26, RCP45, RCP60, and RCP85) is larger than that at present. The most susceptible area is Yunnan province with 80% of the area prone to SOD at extremely high risk in present and future scenarios. The results will be important for monitoring potential high-risk areas in the currently uninfected parts of China.
Two species of Minooa are revised from China and Southeast Asia, and one of these, Minooa carinata Qi, Bae & Li, sp. nov. is described as new to science, and M. acantha Qi,
Bamboo is a unique fiber-reinforced bio-composite with fibers embedded into a parenchyma cell matrix. We conducted axial compression tests on bamboo blocks prepared from bottom to top, and from inner to outer portions of the culm. The apparent Young’s modulus and compressive strength of whole thickness bamboo blocks exhibited slight increases with increasing height along the culm, due to slight increases of fiber volume fraction (V f) from 28.4 to 30.4%. Other blocks showed a significant increase in apparent Young’s modulus and strength from the inner to outer part of the culm wall, mainly owing to a sharp increase of V f from 17.1 to 59.8%. With a decrease of fiber fraction volume there was a transition from relatively brittle behavior to very ductile behavior in bamboo blocks. Results indicated that stiffness and strength of bamboo was primarily due to fiber in compression, and ductility of bamboo was provided by the parenchyma cell matrix acting as a natural fiber-reinforced composite.
In the original publication of the article, the given name and family name of the authors were interchanged. The corrected names are given in this correction.