Salinity stress is one of the most serious factors limiting the distribution and productivity of crops and forest trees. The detrimental effects of salt on plants are a consequence of both a water deficit resulting in osmotic stress and the effects of excess sodium ions on critical biochemical process. A novel approach to improve salt tolerance has been established by using the technology of plant genetic transformation and using loblolly pine (Pinus taeda L.) as model plant. Mature zygotic embryos of loblolly pine were infected withAgrobacterium tumefaciens strain LBA 4404 harbouring the plasmid pBIGM which carrying the mannitol-1-phosphate dehydrogenase (Mt1D) and glucitol-6-phosphate dehydrogenase (GutD). Organogenic transgenic calli and transgenic regenerated plantltes were produced on selection medium containing 15mg/L kanamycin and confimed by Southern blot analysis of genomic DNA. Salt tolerance assays demonstrated that the salt tolerance of transgenic calli and regenerated plantlets were increased. These results suggested that an efficientAgrobacterium tumefaciens-mediated transformation protocol for stable integration of foreign genes into loblolloy pine has been developed and this could be useful for the future studies on engineering breeding of conifers.
Bark samples ofMagnolis officinalis were collected from a 7-year-old trial plantation with 13 provenances in Jingning County of Zhejiang Province on June 25, 2000. The contents of magnolol and honokiol ofM. officinalis were analyzed by the method of HPLC (High Performance Liquid Chromatogram). The results showed that such qualitave traits as the content of magnolol, content of honokiol, total content of key phenol, and the ratio of magnolo to honokiol differ significantly between the provenances. The provenances with a sharpened leaf tip from the western part of Hubei Province has a highest content of phenols, and that with a concave leaf tip from the Lushan Mountain has a lowest content of phenol. All these four qualitative traits were genetically controlled, with a heritability between 0.8342 and 0.9871 in terms of provenance. In addition, both longitudinal and latitudinal geographical variations could be found, with longitudinal variations being dominant. As a result, 3 superior provenances from Wufeng, Enshi and Hefeng of the western part of Hubei as well as 10 high-quality individuals were
Riparian zone is an important component of forested watershed. Species component, structure, and distribution pattern of plant community in riparian zone are different from those of forest far away from the riparian zone because of edge effect and influence of river, and their minimum sampling areas are also different. To study the minimum area and α biodiversity of broad-leaved/Korean pine forest in riparian zone, three 8 m×32 m sampling belts were selected and distributed at elevation of 800 m, 900 m, and 1 000 m. In the riparian broad-leaved/Korean pine forest, mean minimum sampling areas including 60%, 80%, and 90% of total species were 80 m2 (8 m×10 m), 180 m2 (12 m×15 m), and 320 m2 (16 m×20 m) respectively; The corresponding mean minimum areas of non-riparian forest were about 260 m2, 380 m2, and 480 m2; and the former were smaller than the latter. In the riparian zone, species richness, Shannon-Weiner index and species evenness were also higher than those in non-riparian forest. On the contrary, species dominance in forest community was higher than that in riparian zone.
By the method of gradient pattern analysis, twenty plots were set at altitudes of 700–2600 m with an interval of 100 m on the northern slope of the Changbai Mountain. The dissimilarity of respective sub-plots in the same community was measured and the complexity of plant communities at different altitudes was analyzed. The result from binary data of tree species in canopy tree indicated that the sub-plots in the communities, except subalpineBetula ermanii forest, showed comparatively high dissimilarity in species composition. Especially, the dissimilarity index (0.7) of broadleaved/Korean pine forest at low altitudes was obviously higher than other communities. The differences are not obvious between communities referring to dark coniferous forest. Comparatively, the dissimilarity in sub-plots of the communities at altitude of 1400 m was slightly higher than that of other communities, which reflected the complexity of tree species compositions of transitory-type communities. For subalpineBetula ermanii forest, tree species composition was simple and showed a high similarity between sub-plots. The results derived from binary data of shrub showed that the dissimilarity index of shrub species in broadleaved/Korean pine forest at low altitudes was higher than that in other communities, but the divergence tendency wasn’t so obvious as that of arbor species. The dissimilarity derived from binary data of herb and all plant species at different altitudes showed greatly close tendency, and the differences in herb and all plant species between sub-plots were the greatest for the communities of broad-leaved-Korean pine forest and alpine tundra zone.
According to the investigation of sampling area of 6800 m2 on the south slope of Shennongjia Mountain, there were 126 vascular plant species, belonging to 108 genera and 64 families, in the investigated rare plant communities, of which 9 rare plant species were recorded, accounting for 27.3% of the total rare plants. The communities were about 30 m in height and were divided into three layers as tree layer, shrub layer, and herb layer. The flora of the communities had obvious temperate character. Phanerophytes (accounted for 65.9%), Mesophyllous (62.7%), Papyraceous (84.1%), simple leaf (83.3%), un-entire leaf (69.8%) were dominant in life form, leaf size class, leaf texture, leaf form, and leaf margin respectively. According to important value of species, the communities were divided into three types asDavidia involucrata+Litsea pungens community,Cercidiphyllum japanicum +Padus wilsonii community, andPadus wilsonii+Acer mono community. The indexes of species diversity of tree layer had little difference among communities and evenness was high. The results indicated that the communities had complex structure and relative stability.
Due to the importance of riparian zone in maintaining and protecting regional biodiversity, increasingly more ecologists paid their attentions to riparian zone and had been aware of the important effects of riparian zone in basic study and practical management. In this study, 42 sampling belts (10 m×100m) parallel to the bank of Xiangxi River at different elevations in Shennongjia Area were selected to investigate the riparian vegetation and rare plants. 14 species of rare plants were found distributing in riparian zone, accounting for 42.4% of the total rare plant species in Shennongjia Area. The main distribution range of the 14 rare plant species was the evergreen and deciduous mixed broadleaved forest at elevation of 1200–1800 m, where, species diversity of plant community was the maximum at the moderate elevation. The analysis of TWINSPAN divided the 14 rare species into 3 groups against the elevation, namely low elevation species group, moderate elevation species group, and high elevation species group. The analysis of DCA ordination showed similar results to that of TWINSPAN. In the paper, the authors discussed the reasons forming the distribution pattern of rare plant species, and pointed out that the important function of riparian zone on rare plant species protection.
The features of branching and growth studied included height, diameter at breast height (DBH), total number of branches, annual height growth, annual branch elongation in the year of elongating, annual branch number for four consecutive years, diameter of branches of different ages, and diameter of stem where branch-whorl originates. For features of total growth and overall branching, no significant differences were found between families, except for DBH. For annual features, no significant differences were found in annual stem height growth, annual branch elongation in the year of elongation and diameter of branches. In the last four years, differences in number of branches were not significant in the first two years but were significant in the last two year; differences in stem diameter where branch-whorls grow were significant for the four consecutive years. Trend of annual growth and branching features of families can be divided into three types as increasing type, stable type and fluctuating type. Most of families have an increasing type with respect of annual height growth and annual branch elongation, while most families belong to a fluctuating type with annual branch number. The results indicated that in the fifth year after planted in seedling seed orchard, differences between families were mostly insignificant. This result may have two main explanations: one is the growth rhyme in early ages of Masson pine, the other one is the complex paternal components to form the open-pollinated families. Family selection seemed to be not useful based on the result. It is suggested to select some of families in the nursery instead of to use all the families when establishing seedling seed orchards with open-pollinated families from plus-trees.
This study was conducted in Xinkou Experimental Forestry Farm of Fujian Agricultural and Forestry University, Sanming, Fujian Province in January 1999. Taking pure stand of Chinese fir as control, the authors measured and studied the content of organic carbon, content of humic acid (HA), ratio of HA of fulvic acid (FA), and the characteristics of infrared light spectrum and visible light spectrum of soil humus in the mixed forest of Chinese fir and Tsoong’tree. Compared to humus composition in the pure stand of Chinese fir, the content of soil organic C, HA content, and the E4 value of HA for different layers of soil, except for the ratio of HA to FA, showed a significant increase in the mixed forest, while the ratios of E4 to E6 had a little decrease. The infrared light spectrum of humic acid had an absorptive peak at 1650 cm−1. It is concluded that the levels of humification and aromaticity of soil humus are higher in the mixed forest, which is favorable for the improvement of soil structure and nutrient supply, thus improving the soil fertility to a certain degree.
Dark brown forest soil was collected from the upper 20 cm soil layer in Changbai Mountain Research Station of Ecosystem, Chinese Academy of Sciences. The soil was amended with two different forms of nitrogen fertilizers: NO3 as Ca(NO3)2, NH4 + as NH4Cl at the concentrations of 50, 100, 200 and 400 mg kg−1respectively. The experiment was carried out with 2-yr-oldPinus koraiensis seedlings in pot. The pH change of rhizosphere soil and the contents of available Fe, Mn, Cu, and Zn in soil and leaves were analyzed. The result indicated that the addition of NH4-N decreased the rhizosphere pH value, while the addition of NO3-N increased the rhizosphere pH value in contrast with the control treatment. The direction and extent of the pH change mainly depended on N source and its concentrations applied. The rhizosphere pH change had a remarkable influence on the availability of the micronutrients in the rhizosphere, and thereafter affected the nutrient uptake by the seedlings. The contents of available mineral nutrients had a negative correlation with the pH value in the rhizosphere soil. The contents of available mineral nutrients in leaves were positively correlated to the levels of the available nutrients in the rhizosphere soils.
The construction of stone terraces to minimise soil erosion is common throughout Guizhou. This technique, however, has high inherent risk. Stone terraces are usually much higher than those with earth risers. While they trap a greater thickness of soil on the slope they increase the risk of slope failures, reduce moisture and nutrient availability to plants, and thin more soil up slope. The stone risers also threaten long-term productivity. When a riser collapses debris is deposited over the terrace below making farming difficult. These breaches in the terrace focus surface runoff leading to gully formation and increased sediment transport down slope. Artificial drainage systems, often used in conjunction with terracing, compound the risk. These channels prevent precipitation from soaking into the soil. This limits groudwater and soil moisture recharge which reduces the availablity of water for crops and the length of the growing season. The rapid drainage of water from the slope reduces the time of concentration of the catchment resulting in an increase in flood activity. Floods are caused by smaller rainstorm events. They arrive faster and peak quicker and higher than before the channels were constructed. Engineering solutions to soil erosion must therefore be used in conjunction with, and are not as a substitute for, good land management strategies. Furthermore, despite changes in land use practices, and the application of new technologies, there is a maximum amount of production that can be obtained from this land on a sustainable basis.
The competition-density effect of plant populations is of significance in theory and practice of forest management and has been studied for long time. The differences between the two reciprocal equations of the competition-density effect in nonself-thinning populations and self-thinning populations were analyzed theoretically. This supplies a theoretical basis for analyzing the dynamics of forest populations and evaluating the effect of forest management.
Robinia pseudoacacia f.decaisneana is a transfiguration ofRobinia pseudoacacia. For enhancing propagation co-efficient of the species, the experiment of shoot tissue culture ofRobinia pseudoacacia f. decaisneana was conducted in Forestry College of Shenyang Agricultural University from July 1999 to July 2001. The experiment included medium selection of explant induction survival, initial culture, subculture as well as rooting culture, and forming seedling with callus. The results showed that shoot segmentin vitro survive rate is larger in spring than in autumn, and green dense callus could form plantiet. The best medium for initial culture was SH+0.5mg/L BA+0.05mg/L NAA, with a propagation coefficient of 4.1 (per micro-cutting in a month), and for subculture it was B5+0.5mg/L BA+0.05mg/L NAA+10mg/L Glu., with a propagation coefficient of 4.7. The best rooting medium was 1/2MS+0.5mg/L NAA+10mg/L Glu., with a rooting rate of 84.4%. These results provide reference data for reproduction of superior individuals ofRobinia pseudoacacia f. decaisneana.
This paper depicted the physiographic landscape features and natural vegetation situation of study area (the eastern Jilin Province), and expatiates the definition, basic characters and its development of Ecological Land Classification (ELC). Based on the combination of relief map, satellite photography for study area and vegetation inventory data of 480 sample sites, a 5-class and a 15-class ecological land type map was concluded according to 4 important factors including slope, aspect, vegetation and elevation. Ecological Classification System (ECS) is a method to identify, characterize, and map ecosystems. The Ecological Land Type (ELT) was examined and applied initially in eastern Jilin Province.
Eight factors, including forest coverage, fuel load, species composition, elevation, monthly mean temperature, monthly mean relative humidity, monthly mean wind velocity, and monthly mean precipitation of fire season, were considered and the methods of weight, the cumulative probability, ARC/INFO technique, and raster-to-vector conversion were adopted in division of forest fuel type area. Firstly, the electronic maps of forest distribution and administrative divisions were built, then overlaid and transformed to the real-world coordinates. Finally, the forest fuel type areas of Heilongjiang Province including 81 counties were divided into five grades, accounting for 16%, 17%, 17%, 11%, and 38% respectively. The grade I fuel type areas with highest fire danger rating mainly distributed on Daxing’anling Mountains, Xiaoxing’anling Mountains, and Zhangguangcailing Mountains, the grade V fuel type areas mainly centralized on Songnen Plain, Sanjiang Plain, and other Plains, and other forest fuel type areas (grades II, III, and IV) were situated between plains and mountainous areas.
Log volume inspection is very important in forestry research and paper making engineering. This paper proposed a novel approach based on computer vision technology to cope with log volume inspection. The needed hardware system was analyzed and the details of the inspection algorithms were given. A fuzzy entropy based on image enhancement algorithm was presented for enhancing the image of the cross-section of log. In many practical applications the cross-section is often partially invisible, and this is the major obstacle for correct inspection. To solve this problem, a robust Hausdorff distance method was proposed to recover the whole cross-section. Experiment results showed that this method was efficient.
The presence of a thatch layer in established pastures could reduce the contact between broiler litter and soil, thus increasing the potential for surface runoff contamination with litter P. We conducted a laboratory study to evaluate the effect of a thatch layer on the dynamics of water-soluble P in undisturbed cores taken from a pasture. Cores with and without a thatch layer received a surface application of broiler litter (5 t hm−2) and were incubated at 25°C for 56 d. The result showed that on the soil surface the contents of water soluble-P (39 kg hm−2) of the cores with the thatch layer was higher than that (20 kg hm−2) of the cores without the thatch layer. Therefore on well-established pastures fertilized with broiler litter, the presence of a thatch layer might lead to high concentrations of water-soluble P on the soil surface.
With the urgent shortage of forest resource in China, using agro-residues as raw materials of composite become increasingly important. Agro-residue is the most potential fiber resource, which is helpful to sustainable development of composite industries in China. Based on a great deal of researches, this paper summarized and discussed some problems in using agro-residues as raw materials of composites, including raw material preparation, hot-pressing, bonding technology, preventing composite from going moldy. It is proposed that to manufacture the composite of rice straws or wheat straws, the isocayante resin is a suitable adhesive, and the appropriate technologies, bonding, and treatment measures are also needed.
The advances in the application of sterilizing techniques against pest rodents in China are introduced in the paper. The development of chemosterilants, improvements of botanic sterilants, production of new steroid hormone sterilants, introduction of immunosterility and excellent properties of the sterilants are outlined. The “Space Occupation Theory” of sterile techniques is advanced after practice. The botanic sterilants with gossypol and trichosanthin as its main agents were screened and successfully applied in the large area control in the northern forest area of China. The safety of sterilants to non-target animals such as rats, rabbits, dogs, monkeys and chickens was summarized.