干旱胁迫对燕麦叶片气孔和叶肉细胞超微结构的影响

为了解干旱后燕麦解剖结构的变化,以燕麦品种白燕2号为材料,通过盆栽控水试验,设置正常供水、轻度干旱和重度干旱三个不同水分处理(土壤含水量分别为田间持水量的75%、60%和45%),研究了干旱胁迫对燕麦叶片渗透调节物质含量、气孔和叶肉细胞超微结构的影响。结果表明,正常水分条件(对照)下,燕麦叶片脯氨酸和可溶性糖含量较低,表皮细胞皱褶,气孔关闭或微张,叶肉细胞内细胞器形状规则,结构清晰。与对照相比,轻度干旱胁迫下,燕麦叶片脯氨酸和可溶性糖含量增加,叶片表皮细胞饱满,气孔开启度较大,叶绿体形状变圆,近球状,线粒体外被膜膨胀,但结构未见明显损伤;重度干旱胁迫下,叶片脯氨酸和可溶性糖含量极显著增加,表皮细胞干瘪,气孔保卫细胞膨胀,气孔关闭,气孔器下陷。重度干旱胁迫下,燕麦叶绿体和线粒体受到的损伤较大,叶绿体内基粒、基质类囊体降解,出现较大的空腔;线粒体外被膜断裂,内含物流失;细胞核染色质凝聚,叶绿体之间出现嵌合现象。因此,干旱胁迫能诱导燕麦叶片渗透调节物质的积累和细胞超微结构的改变,渗透调节物质增幅和细胞超微结构的破坏程度随着土壤有效水分含量的降低而上升,但在细胞超微结构上也出现抗性反应,表明燕麦具有较强的抗旱性。

Effect of Drought Stress on Stomata and Ultrastructure of Mesophyll Cells of Oat Leaf

The variety of oat Baiyan 2 were used to investigate the effect of soil drought stress on the contents of osmotic regulators,the stomata and ultrastructure of mesophyll cell under pot culture condition.Soil water content is 75％,60％ and 45％ of the water holding capacity in the field under normal water,light drought stress and severe drought stress,respectively.The result showed under normal water condition,the contents of proline and soluble sugar were low,the epidermal cells were wrinkled,and the stomata were closed or slightly opened.The shape of organelles in mesophyll cells was regular and the structure was clear.Under light drought stress,the content of proline and soluble sugar in oat leaves increased,the epidermal cells were full,the stomatal opening was larger,the chloroplast and mitochondria changed slightly,but the structure did not show obvious damage.Compared with the control,under the severe drought stress,the content of proline and soluble sugar in leaves increased significantly,and the epidermal cells were shrunk;The stomatal guard cells expanded,the stomata was closed,the stomatal apparatus was sagged;Under the condition of severe drought stress,the chloroplast and mitochondria in the mesophyll cells caused great damage,granum lamellae and stroma lamellaein the chloroplast were degraded,and the larger cavity appeared inside;Membrane of mitochondrial broken,inclusions loss;in addition,nuclear chromatin condensed,and there was chimerism between chloroplasts.It can be seen that drought stress induced the accumulation of osmotic regulators and structural change.The growth rate of osmotic regulators increases rapidly with the decrease of soil water content,and the degree of structural damage increases,the oat also showed strong drought resistance in structure.