菜心小孢子发育时期与花器官形态的相关性

研究菜心小孢子不同发育时期的细胞学特征及其与花器官外部形态的相关性,为直接从花器官外部形态特征来判断小孢子发育时期提供依据。结果表明,菜心小孢子发育分为四分体时期、单核期和双核期,各时期特征明显。菜心小孢子发育时期与花蕾和花药外部形态特征密切相关,供试菜心材料中处在单核靠边期的花蕾纵径为3.05～3.39 mm,花萼长为3.25～3.46 mm,花瓣长为2.10～2.33 mm,瓣萼比为0.63～0.71,花药长为2.57～2.89 mm、瓣药比为0.77～0.85,适合作为不同材料花蕾最佳取样时期的鉴定指标。处在单核靠边期的花器官外观特征表现为花蕾饱满,萼片绿色并包被着花冠,花瓣和花药均为浅黄色,花药略长于花瓣。可见,依据花器官形态特征可判断菜心小孢子的发育时期及所对应的选蕾标准。

Correlation of Microspore Development Period and Flower Morphological Characteristics of Chinese Flowering Cabbage

The cytological characteristics of microspores in Chinese flowering cabbage at different developmental periods were studied to reveal the relationship between microspore development and buds morphology, which would provide evidences for the culturing of anthers and microspores. The results showed that the microspore developed in tetrad, early- or mid-uninucleate, late-uninucleate and binucleate stages obviously. The microspore development showed correlativity with the morphological characteristics of buds and anthers. The buds 3.05-3.39 mm in height, the calyx 3.25-3.46 mm in length, the petal 2.10-2.33 mm in length, the ratio of flap to calyx 0.63-0.71, the anther 2.57-2.89 mm in length, and the ratio of flap 0.77-0.85 were discovered to contain microspores at the late uninucleate. These were suitable for the identification of optimal sampling period of flower buds in different materials. At the late uninucleate stage, it was necessary that the anthers should be covered by the sepal, the anthers slightly longer than petals, and the flower bud was full, the petals and anthers showed pale yellow. Therefore, we can judge the development stage of Chinese flowering cabbage microspore by morphological characteristics of flower organs so as to define the standard of bud selection in correspondence with the optimal stage of anthers culture.