甘南地区歪头菜的选择性败育及结实格局

歪头菜是甘南地区极具利用价值的饲用植物,可为家畜提供丰富的蛋白质,因此加强种子生产是歪头菜在该地区种植推广的基础。本实验着眼于歪头菜生殖过程中的选择性败育,研究了歪头菜花期不同阶段和花序不同位置果实和种子的结实格局,得出以下结果:1)2龄植株盛花期花序上结荚率最高(41.6%),5龄植株初花期花序上结荚率最高(28.8%),两者均为末花期花序上结荚率最低,且所结荚果内种子数为0。2)2龄和5龄植株均为花序中部结荚率最高,分别为43.9%和41.6%,但上、中、下部位荚果内的种子数无显著(P>0.05)差异。3)荚果内靠近柱头端和靠近小花柄端的胚珠败育的可能性更大,荚果中部(从柱头端算起第2,3,4,5位置)的胚珠形成种子时更易出现交替败育的趋势。4)每序结荚数随着每序单花数的增加呈现先增加后减少的趋势,当每序单花数为20朵时,每序结荚数达到最大8个。由上述结果推测,选择性败育引起的歪头菜果实和种子的结实分配格局可能是资源限制的原因,也可能是植物对特殊生境的一种繁殖策略,然而这一结果影响了歪头菜的实际种子产量。

Selective abortion and fruit-set pattern ofVicia unijuga in Gannan Tibetan region

Vicia unijuga is a valuable forage species in Gannan Tibetan region, and its seed production is important for planting and popularizing of V. unijuga in this region. Fruit-set patterns and selective abortion of flowers of V. unijuga in Gannan Tibetan region were studied. The results showed that: 1) In terms of time, the highest fruit set was observed for the two-year-old population (28.8%) at the full-bloom stage and for the five-year-old population (41.6%) at the early flowering stage. For both populations, the lowest fruit set (3.0% and 1.1%) was found at the end of flowering stage. There was no appreciable difference (P>0.05) in the seed number per pod between the early flowering and full-bloom stages for the two populations, and the seed number per pod at the end of flowering stage was zero; 2) On an inflorescence, the highest fruit set was in the middle of the inflorescence for both populations. The two-year-old population was 43.9% and the five-year-old population was 41.6%. However, the seed number per pod exhibited no significant difference (P>0.05) in each part of the inflorescence for the two populations; 3) The ovules closing to the stigma and pedicel were more likely to abort. The ovules in the 2^nd, 3^rd, 4^th and 5^th positions starting from the side of the stigma would have higher possibility to form mature seeds and showed alternating abortion patterns; 4) The number of fruit per inflorescence was lower than eight, which was not affected by the number of flowers on the inflorescence. It may indicate that the selective abortion of the fruit and seed is caused by the resource limitations, or is a reproductive strategy of V. unijuga that the redundant flowers are selectively aborted by the plants, suggesting that the actual seed yield of V. unijuga will be influenced by the selective abortion.