澳洲杨(大戟科)胚珠及其种子附属结构的个体发育研究

以澳洲杨的胚珠及其种子为材料,运用光学显微镜和电镜扫描的方法对其从胚珠发生直到种子成熟的个体发育过程和结构进行观察,同时与鸭脚西番莲的种子附属结构的发育过程进行对比研究。结果表明:(1)澳洲杨的珠孔类型为外珠孔类型,种子附属结构起源于珠孔而非珠柄,其为种阜,而非假种皮。(2)鸭脚西番莲的珠孔类型为内珠孔类型,种子附属结构起源于珠柄,并且最终将珠孔包被,其为真正的假种皮结构。通过种阜与假种皮的不同个体发育过程,建立了大戟科种阜与假种皮的不同发育模式,并对种子附属结构的生物学功能及其暗示的不同植物进化路径进行了讨论。

Ontogeny of the Ovule and Fleshy Seed Appendage in Homalanthus populifolius (Euphorbiaceae)

The ontogeny of the ovule and fleshy seed appendage in Homalanthus populifolius (Euphorbiaceae) were studied with the light microscope and SEM(Scanning Electron Microscope) and compared with the development of fleshy appendage of Passiflora citrina (Passifloraceae).The results showed that:(1)The micropyle type of H.populifolius is exostomatic.The fleshy seed appendage develops from the micropyle,which does not come from funiculus,should be called caruncula,not aril.(2)The micropyle type of Passiflora citrina is endostome.The fleshy seed appendage of P.citrina develops from funiculus and will cover the micropyle later.This is the aril.A detailed discussion between the caruncula and aril is presented.The model of caruncula and aril are set up and its biological significance is discussed.