摘要
文冠果(Xanthoceras sorbifolia Bunge)是重要的生物能源植物。文冠果花一般可分为两种类型,一种是雄蕊败育的雌花,一种是雌蕊败育的雄花。但关于文冠果雌雄花败育过程的研究至今尚无报道。本文用数码相机和扫描电子显微镜观察并比较了文冠果雌雄花发育过程的结构变化。结果显示:(1)性别分化前期,即4月中旬两种类型花在形态上无明显差别;(2)性别分化中期,即4月下旬,雌雄花分化开始表现明显差别,雌花雄蕊逐渐退化,而雌蕊3心皮逐渐愈合发育形成花柱、柱头和子房,花柱由短圆柱形发育成三棱形,再逐渐发育成圆柱形;雄花心皮不能发育成明显的花柱、柱头和子房,3心皮独立存在,逐渐退化;(3)性别分化后期,即5月初,雌花雄蕊花丝停止伸长,花药不饱满,雌蕊花柱继续伸长至雄蕊两倍,柱头3基瓣外翻,乳突状细胞密生且逐渐发育成长圆柱形;雄花内圈4枚雄蕊花丝继续伸长,而外圈4枚雄蕊花丝先短于内圈4枚雄蕊,形成四强雄蕊,后伸长至一致,随后花药开裂散粉,而雌蕊完全干缩至雄蕊内侧基部。综上所述,文冠果两种类型花的形成是早期花芽分化完全的两性花发育到后期,由其中一种性器官退化的结果。
An extremely low fruit set severely inhibits productivity improvement in Xanthoceras sorbifolia Bunge,an important bio-energy plant： female flowers have abortive stamens,and pistils of male flowers abort before pollination.Examination of the development process in both types of flowers using a digital camera and a scanning electron microscope showed no significant difference between the two types at the early sex-differentiation phase（middle of April）.At the mid sex-differentiation phase（late April）,stamens in female flowers began to degenerate,and carpels of the pistil gradually began to fuse and developed into the style,stigma,and ovary;the three carpels in male flowers remained separate and gradually withered without further development.At the late differentiation phase（early May）,the style in the female flowers elongated to double the length of the stamens,and the exstrophy triguaiacyl petal of the stigma developed into a long cylinder copiously lined with closely arranged papillary cells.By that time,the male flowers had developed two rings of stamens,but the pistil had shriveled totally and lay at the base of the stamens.Thus both female and male flowers in X.sorbifolia probably arise from common hermaphrodite flowers,the differentiation being the result of selective degeneration of either the female or male sexual organs towards the end of flower development.
出处
《电子显微学报》
CAS
CSCD
2012年第2期154-162,共9页
Journal of Chinese Electron Microscopy Society
基金
国家自然科学基金资助项目(No.30870436)
江苏省自然科学基金资助项目(No.BK2011444)
关键词
文冠果
雌花
雄花
发育过程
Xanthoceras sorbifolia Bunge
female flowers
male flowers
development process
