Cytological observation of the microspore development of Chinese kale and false pakchoi

Abstract

The development process and morphology of the microspores in Chinese kale and false pakchoi were observed by using the whole stain-clearing technique. The results showed that the morphological characteristics of microspores were not only extremely similar, but were also in their development processes. The microspores at tetrad stage showed an arrangement of tetrahedral type, and after being released and passing through two mitoses, they developed gradually to form rotundly-shaped mature pollen grains containing three nuclei, one bigger alimentation nucleus and two smaller similar-sized generative nuclei. Determination of bud sizes at four typical microspore developmental stages revealed that the bud size had a stable heredity at each development stage of the microspores. The ratio of the bud length at the late uninucleate stage to the largest bud length differed little between Chinese kale and false pakchoi, ranging from 0.37 to 0.45 with an average of 0.41, though there was significant difference among their cultivars. It was concluded that the length of buds at late uninucleate stage can be estimated for undetermined cultivars of these two Brassica crops by multiplying the largest bud length with the following coefficient or regression equation: Y = 0.3898X+0.1503, where X is the length of the largest bud.

Key words： Chinese kale; false pakchoi; microspore; late uninucleate stage

Acknowledgements

This work was supported by the Applied Basic Research Project of China (No. 2006J1-C0191), the Agricultural Sci-Tec Project of Guangzhou, Guangdong Province, China (No. GZCQC0702FG06054-3), and the Fund for the Doctoral Program of Guangdong Academy of Agricultural Sciences, China (No. 05-Doctor-06).

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