Factors affecting seed set in the crosses between Dendranthema grandiflorum (Ramat.) Kitamura and its wild species
Factors affecting seed set in the crosses between Dendranthema grandiflorum (Ramat.) Kitamura and its wild species
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影响大花菊与其野生种杂交结实的因素
DOI：
10.1007/s10681-009-0005-6
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发表时间：
2010-01-01
期刊：
影响因子：
1.9
通讯作者：
Hou, Xi-Lin
中科院分区：
文献类型：
--
作者：
Sun, Chun-Qing;Chen, Fa-Di;Hou, Xi-Lin
菊花(Dendranhema gradiflorum(Ramat.)北村及其野生种，严重造成结实率低，从而降低育种效率。为了揭示导致结实率低的因素，我们研究了桔梗与三个野生种南京丹(D.nankingense(Nakai)Tzvel.)、野百合(D.INGUM(L.)德斯穆尔。和草莓D.zawadskii(Herb.)茨维尔。采用石蜡切片、光镜、荧光和扫描电子显微镜等技术。结果表明，3个野生种的花粉生活力在20%~25%之间。南京花与桔梗杂交，授粉后极少有花粉粒在柱头上萌发，多数为异常萌发。此外，12%的子房在授粉后第8天观察到正常胚胎，此后所有胚胎都败育。另外两个杂交组合，授粉后有大量花粉粒在柱头上萌发，花粉管正常穿透柱头。此外，在授粉后8~15d，桔梗与野牡丹杂交的子房中有50%以上的胚胎发育正常，结实率为59%。在桔梗与杂交种的杂交中，52%的子房在授粉后8天观察到了正常的胚胎。然而，在那之后，大多数胚胎退化，结实率只有9%。这些数据表明，花粉生活力对三个杂交组合的结实率没有显著影响。柱头上极少的萌发花粉和受精前大多数花粉管的异常生长以及胚胎败育是导致桔梗与南京花杂交失败的主要因素，而只有胚胎败育才是导致桔梗与狼毒杂交结实率低的主要因素，而桔梗与印度石竹杂交不存在任何障碍。
Reproductive barriers often exist in the crosses between Dendranthema grandiflorum (Ramat.) Kitamura and its wild species and seriously result in low seed set, consequently reducing breeding efficiency. For the purpose of revealing the factors leading to low seed set, we investigated pollen viability, germination behavior of pollen grains on stigmas and embryo development in the crosses between D. grandiflorum and three wild species, D. nankingense (Nakai) Tzvel., D. indicum (L.) Des Moul. and D. zawadskii (Herb.) Tzvel. using technique of paraffin section, and light, fluorescence and scanning electron microscopy. The results indicated pollen viability of three wild species ranged from 20 to 25%. In the cross between D. grandiflorum and D. nankingense, very few pollen grains germinated on stigmas after pollination and most of them germinated abnormally. In addition, normal embryos were observed in 12% ovaries at 8 days after pollination and thereafter all the embryos aborted. In other two crosses, many pollen grains germinated on stigmas and pollen tubes penetrated stigmas normally after pollination. Moreover, normal embryos were observed in over 50% ovaries from 8 to 15 days after pollination in the cross between D. grandiflorum and D. indicum, and seed set was 59%. In the cross between D. grandiflorum and D. zawadskii, normal embryos were observed in 52% ovaries at 8 days after pollination. After that, however, most embryos degenerated and seed set was only 9%. These data suggest that pollen viability has no significant effects on seed set of the three crosses. Very few germinated pollen grains on stigmas and abnormal growth of most pollen tubes before fertilization, and embryo abortion are the main factors causing failure of the cross between D. grandiflorum and D. nankingense, whereas only embryo abortion is a main factor resulting in low seed set in the cross between D. grandiflorum and D. zawadskii and no barriers occur in the cross between D. grandiflorum and D. indicum.