玉米籽粒败育多发生于穗轴顶部。顶部籽粒除位势上处于劣势外,还常与分化及授粉时间较晚事件相关。近年来,越来越多的学者认为授粉晚是籽粒败育的原因之一。而推迟授粉事件是否直接影响籽粒生长,目前还缺少较为明确的证据。本研究通过对先后吐出苞叶的花丝进行特定时间的授粉,研究了正常生长条件下推迟授粉对玉米籽粒生长的影响。结果表明,推迟授粉对先授粉籽粒的生长影响较小,先授粉籽粒粒重无显著差异；但显著减低了后授粉籽粒的粒重,先玉335及登海605两个品种表现一致。进一步研究发现,后授粉籽粒的生长动态,即干物质积累动态与正常授粉籽粒并不存在显著差异,先玉335、登海605、郑单958和大成168四个品种表现一致。说明无胁迫条件下,推迟授粉仅仅相对推迟了后授粉籽粒的生长发育时期,生长时间缩短,从而影响了籽粒粒重形成。因此,正常生长条件下推迟授粉事件并未影响籽粒生长,胁迫条件下的其他因素可能才是造成籽粒败育的根本原因。
英文摘要:
In maize, kernel abortion was always occurred in the apical region of the ear. The apical kernel was not only showed the disadvantages in position but related to the late events of differentiation and pollination. In recent, many researchers suggested that delayed pollination was the cause of kernel abortion. However, whether delayed pollination was causal link to kernel abortion is still unclear. Experiment was carried out by delayed pollination on late emergence silks under normal growth conditions. We found that delayed pollination had little effect on growth and development of the early pollinated kernel. However, delayed pollination significantly reduced the weight of late pollinated kernel, Xianyu335 and Denghai605 hybrids both showed the same trend. Our results also showed that there was no significantly difference in dry matter accumulation between late pollinated kernel and normal kernel with same time after pollination, Xianyu335, Denghai605, Zhengdan958 and Dacheng168 hybrids all showed the same trend. In general, delayed pollination only delayed and shortened the development of late pollination kernel development, thus affected kernel weight under no stress conditions. It was mentioning that factors other than delayed pollination likely play key role in controlling kernel development under stress condition.
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