干旱胁迫对小麦颖果发育的影响

Effect of drought stress on caryopsis development of wheat

以扬麦16为材料,在小麦幼苗返青期至颖果成熟期内进行干旱处理,研究小麦颖果组织在干旱胁迫下细胞学结构的变化特征。结果表明:(1)在颖果发育过程中,干旱胁迫能促进前期颖果生长,但抑制后期颖果生长。(2)干旱胁迫在颖果发育早期促进果皮组织发育,而在后期阻碍果皮细胞的程序性死亡,降低果皮中淀粉体的降解速率。(3)干旱胁迫下颖果胚乳组织在早期发育较快,但在后期胚乳细胞的进一步生长受到抑制,胚乳淀粉体的积累减少。(4)干旱胁迫下小麦颖果在发育早期胚组织分化早、发育快,但随着干旱的持续,胚体积的进一步扩张受阻,营养物质积累下降。综合而言,干旱胁迫通过改变颖果各组织结构发育影响颖果生长发育,总体表现为在发育前期促进颖果生长,此后随着干旱的持续,阻碍颖果的进一步发育和成熟。

In order to clarify the structural changes of wheat earyopsis in response to drought,Yangmai 16 was used as the material and treated with drought stress during the period from plant regreening to caryopsis maturity stage. Micro- graphs of caryopsis tissue were obtained using resin semi-thin slice and microscopic observation technology and were ana- lyzed by Image-Pro Plus. The change characteristics of cytological structure of wheat caryopsis under drought stress were investigated. The main results were as follows： （1） In the process of caryopsis development, drought stress can promote the growth of caryopsis at early stage, but inhibited its growth at later stage. （2） Drought stress promoted the develop- ment of pericarp tissue at early stage of caryopsis development, but prevented the PCD of pericarp cells and decreased the rate of starch granule degradation in pericarpat later stage. （3） The endosperm grew faster at early stage under drought stress, but the further growth of endosperm cells was inhibited and the starch granule accumulation decreased. （4） When the wheat was subjected to drought, the embryo differentiated early and grew fast at previous development stage of cary- opsis. But the further expansion of embryo volume was restrained and the accumulation of nutrients decreased with the persistence of drought. These results suggest that drought stress could affect the growth and development of caryopsis by changing the structure of caryopsis tissue. In summary, the development process of drought-stressed wheat caryopsis was accelerated at early stage hut continuous drought hindered the further development and maturity of caryopsis.