青秆竹花的解剖观察与分析

为明确自然状态下青秆竹(Bambusa tuldoides)不同发育阶段花器官的形态以及雌雄配子体的发育状态,总结其败育类型,该文通过采用解剖和切片等方法对青秆竹花器官的各部分外观形态以及雌雄配子体的发育过程进行观察,并分析其结实率低下的原因。结果表明:(1)青秆竹小穗为无限花序,下部的小花先发育,但基部具有潜伏芽,因此又具有有限花序的特征;小穗柄不发达,簇生花枝节部。(2)每朵小花拥有内、外稃各1枚,花药6枚,浆片3枚,雌蕊1枚;浆片透明,边缘具有发达的纤毛;子房具棱,子房上部具绒毛,子房1室,侧膜胎座,倒生胚珠,三分枝羽状柱头。(3)青秆竹花药具有4个药室,花药壁由表皮、药室内壁、中层、绒毡层4层结构组成;绒毡层为腺质型,花药发育后期极度退化;小孢子母细胞分裂类型为连续型,产生两边对称型小孢子,花粉粒细胞成熟后为3核。(4)雄蕊和雌蕊出现多种败育类型,可能是导致结实率低的主要原因。综上结果表明,青秆竹花器官的形态结构发育正常,而雌雄配子体发育过程中出现异常,造成了其结实率低。

Anatomical observation and analysis on floral of Bambusa tuldoides

In order to clarify the morphology of floral organs and the development status of male and female gametophytes at different development stages of Bambusa tuldoides in wild, and to summarize their abortion types, the appearance morphology of each part of floral organs and the development process of male and female gametophytes of B. tuldoides were observed by means of anatomy and sectioning, and the reasons for the low seed-setting rate were also analyzed. The results were as follow:(1)The spikelets of B. tuldoides were of infinite inflorescences. The florets in the lower part of the spikelets developed first, and there were latent buds developed at the base, which had the characteristics of definite inflorescence; The petioles of spikelets were undeveloped, and the spikelets developed in cluster at each node of the floral branch.(2)Each floret had 1 palea, 1 lemma, 6 stamens, 3 lodicules and 1 pistil; The lodicule was transparent and had well-developed cilia on the edge; The ovary had prismatic protrusions and the upper part of which had villi, and was unilocular and lateral membranous with a anatropous ovule. The stigmas were three-lobed and feathery.(3)The anther of B. tuldoides had four sporangia, and the anther wall was composed of four layers, epidermis, endothecium, middle layer and tapetum; The tapetum was glandular, and degenerated completely after maturity; The meiosis was successive and the microspore tetrads were bilaterally, and the mature pollen grains were three-celled.(4)Several abortion types were found in pistils and stamens, which might be the main reasons for the low seed-setting rate of B. tuldoides. All the above results indicate that the morphological structure of B. tuldoides floral organs is normal, while the female and male gametophytes developed abnormally, which cause the low seed setting rate.