花后低温对小麦胚形态发育的影响

为探明花后低温对小麦胚形态发育的影响,以半冬性小麦品种烟农19和春性小麦品种扬麦15为材料,人工模拟花后低温,采用树脂切片、显微结构观察及Image-Pro Plus软件图像分析等技术,研究小麦胚在花后低温下的形态变化。结果发现：（1）低温处理后两小麦品种胚的脱氢酶活性均降低,扬麦15的降幅大于烟农19;（2）低温延迟了小麦胚的发育进程,影响胚面积的增长和结构的分化;（3）低温影响盾片细胞发育,抑制盾片上皮细胞的伸长和底部上皮细胞层数的增加,同时使薄壁细胞贮藏物质增多;（4）低温对小麦胚分化过程影响较大,对小麦胚芽分化的抑制作用较明显,对胚根分化影响不明显,同时低温还抑制胚轴细胞数目的增加、体积的增长和贮藏物质的积累;（5）低温影响胚乳输导细胞的发育,减慢输导细胞解体进程。以上结果表明,花后低温使小麦胚结构分化延迟、体积增加减慢;春性小麦胚发育进程对花后低温的响应程度大于冬性小麦。

Effect of Low Temperature after Anthesis on MorphologicalDevelopment of Wheat Embryo

In order to explore the effect of low temperature after anthesis on the morphological development of wheat embryos,the semi winter wheat cultivar "Yannong 19" and spring wheat cultivar "Yangmai 15" were used as experimental materials in this study.The artificially simulated low temperature treatment was implanted after anthesis,and the resin slicing,microstructure observation and analysis of Image-Pro Plus software were used to explore the morphological changes of wheat embryo under low temperature after anthesis. The results showed that: (1) The activity of dehydrogenase in wheat embryo decreased under low temperature treatment,and the significance of Yangmai 15 was more obvious than that of Yannong 19.(2) Low temperature delayed the developmental process of wheat embryo,and affected the increase of embryo area and the differentiation of embryo structure.(3) Low temperature affected the development of scutellum cells,inhibited the elongation of epithelial cells and the number of epithelial layers at the bottom of scutellum,and increased the storage substances in parenchyma cells.(4) Low temperature had a great effect on the process of wheat embryo differentiation,and had a significant inhibitory effect on wheat germ differentiation,but had no significant effect on wheat radicle differentiation.At the same time,low temperature also affected the increase of the number and volume of hypocotyl cells and the accumulation of storage substances.(5) Low temperature treatment also affected the development of the conducting cells and slowed down the disintegration process of the conducting cells.The above results indicated that the low temperature after anthesis delayed the structural differentiation of wheat embryos and slowed down the volume enhancement. The response of embryo development of spring wheat to low temperature after anthesis was greater than that of winter wheat.