Abstract:

The wild resources of Medicago falcata in Xinjiang were taken as the materials in order to research the technique of haploid breeding (DH line). And the cytological characteristics and the morphological characteristics of bud and anther on the various stages of microspore development were observed. The correlation between microspore development period and floral organ morphology was studied. The results showed that the microspore development of Medicago falcata had four stages including tetrad, early and mid-nucleate, late-uninucleate, binucleate. The cytological characteristics of four stages were obvious. The bud height and petal length showed extremely significant difference among different stages of microspore development, while other morphological characteristics did not. So the bud height and petal length can be used as indicator for judging microspore development. The anther size had no significant difference among different stages of microspore development, but anther color changed significantly, from canary yellow to deep yellow gradually. Bud height and petal length were 3.61～4.32 mm and 2.68～3.61 mm at the late-uninucleate stage, respectively, while petal emerged from sepal.

Key words: Medicago falcata L., Microspore, Development period, Floral organ morphology

摘要：

以新疆野生黄花苜蓿（Medicago falcata）为材料，观察其小孢子发育各时期的细胞学特征及花蕾和花药形态特征，并研究黄花苜蓿小孢子发育时期与花器形态的相关性，以期为单倍体培养（DH系）的育种方法提供依据。结果表明：黄花苜蓿小孢子发育分为4个时期，分别为四分体时期、单核早中期、单核靠边期、双核期，且各时期有明显的细胞学特征；试验材料的花蕾纵径和花瓣长在小孢子发育4个时期之间均表现极显著差异，其它花器形态指标只是部分时期之间差异显著，因此花蕾纵径和花瓣长适宜作为小孢子发育时期的判断依据；小孢子发育不同时期花药大小差异不显著，花药颜色变化明显，由淡黄色逐渐变为深黄色；小孢子处于单核靠边期时，花蕾纵径和花瓣长度分别在3.61～4.32 mm和2.68～3.61 mm之间，此时可见花瓣微露出萼片。

关键词: 黄花苜蓿, 小孢子, 发育时期, 花器形态