FACULTATIVE APOMIXIS IN ERAGROSTIS-CURVULA
FACULTATIVE APOMIXIS IN ERAGROSTIS-CURVULA
复制标题
DOI：
10.2135/cropsci1976.0011183x001600060017x
复制
发表时间：
1976-01-01
期刊：
影响因子：
2.3
通讯作者：
BASHAW, EC
中科院分区：
文献类型：
--
作者：
VOIGT, PW;BASHAW, EC
已有报道表明，垂穗细叶草[Eragrostis curula(Schrad.)Nees]，通过有性生殖或专性无融合生殖(双孢子生殖)繁殖。最近的研究表明，该物种的某些植物是兼性的无融合生殖。研究了草地早熟禾兼性无融合生殖的细胞学基础，认为繁殖细胞学与杂交种及其亲本后代的表现有关。无融合生殖品系的大孢子母细胞(MMC)较大或较晚，由珠被大小决定。这些MMC的发育是通过胚囊的直接形成(双孢子)发生的，或者通过延迟减数分裂而形成线性四分体。对具有这两种生殖细胞学类型的植物的后代测试表明，这些模式表明兼性无融合生殖。有性植株中未观察到后期大孢子母细胞显著增大或减数分裂延迟。有性植株与高度无融合生殖的普通无融合生殖杂交种可以有性繁殖或兼性无融合生殖。有性植株自花授粉时，不产生无融合生殖后代。所研究的有性植物可能缺乏表达无融合生殖所需的所有基因。在大多数实验品系中观察到的一致性，在一些无融合生殖杂交种中的低有性水平，以及许多变异植株的活力下降，表明兼性无融合生殖不会太大地阻碍弯孢草品种的发育和维持。
Previous reports indicate that weeping lovegrass, [Eragrostis curvula (Schrad.) Nees], reproduces either sexually or by obligate apomixis (diplospory). Recent studies demonstrated that certain plants of this species are facultative apomicts. The cytological basis for facultative apomixis in weeping lovegrass was studied and reproductive cytology was related to performance of progeny from lovegrass parents and hybrids. Enlarged or late megaspore mother cells (MMC), as determined by integument size, were observed in apomictic strains. Development from these MMC occurred by direct formation of the embryo sac (diplospory), or by delayed meiosis resulting in the formation of a linear tetrad. Progeny tests of plants with both types of reproductive cytology suggested that these patterns indicated facultative apomixis. Late, greatly enlarged megaspore mother cells or delayed meiosis in sexual plants was not observed. Hybrids between sexual plants and highly apomictic common weeping lovegrass were observed to reproduce either sexually or by facultative apomixis. Sexual plants, when self-pollinated, produced no apomictic offspring. The sexual plants studied probably lacked all necessary genes for expression of apomixis. The uniformity observed in most experimental lines, the low level of sexuality in some apomictic hybrids, and the reduced vigor of many of the aberrant plants suggested that varietal development and maintenance in E. curvula is not hindered too greatly by facultative apomixis.