湖北黄精大小孢子发生及雌雄配子体发育

【目的】研究湖北黄精花部形态结构特征和大小孢子发生及雌雄配子体发育过程，以丰富黄精属植物的生殖生物学理论，为进一步开展湖北黄精的品种选育提供依据。【方法】以不同发育时期的湖北黄精花芽为试验材料，用显微观察法观察花部形态结构特征，石蜡切片技术对单花雌雄蕊进行切片观察。【结果】湖北黄精的花被为白色或淡黄绿色，花被筒近喉部稍缢缩；具6枚雄蕊，花丝下端与花被合生，花药开裂方式为纵裂；雌蕊子房上位，3心皮，花柱与子房等长。湖北黄精花药壁由4层细胞组成，成熟的绒毡层具多核，绒毡层发育类型为分泌型；小孢子母细胞减数分裂为连续型，四分体呈左右对称型排列，成熟花粉粒为2-细胞型；存在小孢子发育不同步的现象。雌蕊胚珠具双珠被、厚珠心；四分体呈直线型排列，胚囊发育类型为蓼型；存在双胚囊胚珠现象。在雄蕊的花药壁和雌蕊的子房壁都观察到有束状草酸钙针晶。【结论】湖北黄精雌雄蕊具有较原始的发育特征，虽然在发育过程中都存在异常现象，但雄蕊最终能形成正常的雄配子体，雌蕊低频率的双胚囊现象对总体受精结果影响很小。湖北黄精杂交育种可以选择花药开裂前一时期的花粉，花药壁和子房壁观察到的束状草酸钙针晶无法作为湖北黄精物种鉴定的...

Sporogenesis and Gametogenesis in Polygonatum zanlanscianense Pamp.

[Objective] In order to enrich the reproductive biology theory of Polygonatum Mill.?and provide the basis for further breeding of Polygonatum zanlanscianense Pamp., the morphological structure characteristics, megasporogenesis and microsporogenesis, and the development process of male and female gametophytes of Polygonatum zanlanscianense Pamp. were studied. [Method] The flower buds of Polygonatum zanlanscianense Pamp. at different developmental stages were used as experimental materials. The morphological and structural characteristics of the flowers of Polygonatum zanlanscianense Pamp. were observed by microscopic observation, and the single flower pistil and stamen of Polygonatum zanlanscianense Pamp.were observed by paraffin sectioning technique.[Results] The perianth of Polygonatum zanlanscianense Pamp. is white or yellowish green, and the perianth tube is slightly constricted near the throat. It has 6 stamens, the lower end of filaments and anthers are united, and the anther is longitudinally split. The pistil ovary is superior, each ovary consists of 3 carpels, and the style is equal to the ovary. The anther wall of Polygonatum zanlanscianense Pamp. was composed of epidermis, endothecium, middle layer and tapetum with one layer each. The mature tapetum had multiple nuclei, and the development type of tapetum was secretory. The meiotic division of microspore mother cells was continuous, there were obvious diads, tetrads were arranged symmetrically, and mature pollen grains were 2-cell type. There is a phenomenon of asynchronous microspore development between different anthers of the same flower and different pollen sacs of the same anther. Ovule in pistil ovary with double integument, thick nucellum. The tetrad formed by meiospore mother cell meiosis was linear, the three megaspore end degenerated and disappeared, and the functional megaspore end developed into 7-cell and 8-nucleus embryo sac, the embryo sac development type was polygonum. The phenomenon of double embryo sac ovule in Polygonatum zanlanscianense Pamp. was observed. The calcium oxalate crystals were observed in the anther wall of the stamen and the ovary wall of the pistil. [Conclusion] The stamens and pistils of Polygonatum zanlanscianense Pamp. have more primitive development characteristics. Although there are abnormal phenomena in the development process, such as the asynchronous meiosis of microspore mother cells, the appearance of double embryo sacs in ovules, stamens can eventually form normal male gametophytes and the low frequency of double embryo sacs in pistils does not affect the fusion of male and female gametophytes.The microspores of Polygonatum zanlanscianense Pamp. were mature before the anther dehiscence, and the pollen of the previous period of anther dehiscence could be selected for cross breeding. The bundle-shaped calcium oxalate needles observed in anther wall and ovary wall cannot be used as the basis for species identification of Polygonatum kingianum.