【作者】 杨瑞丽；

【导师】 王迎春；

【作者基本信息】 内蒙古大学 ， 植物学， 2004， 硕士

【摘要】 内蒙古西鄂尔多斯荒漠区拥有非常丰富的灌木资源，它们对于干旱高温多风沙的恶劣气候环境不仅具有各自独特的适应方式，同时部分早生小灌木还具有共同的生长方式—劈裂生长。本文选取分布于该地区典型劈裂生长的植物—长叶红沙为研究对象，探讨劈裂生长发生过程的细胞学特征。同时，以同一生境下进行劈裂生长的长叶红沙、红沙以及无劈裂生长现象的半日花为研究对象，对其内源激素和膜系统保护酶进行比较研究，进一步探讨劈裂生长的生理调节机制以及对环境的适应性。研究结果如下： 1．长叶红沙劈裂发生过程的细胞学特征与绵刺极其相似，劈裂生长首先在茎基部发生，当长叶红沙植株生长到一定阶段的时候，劈裂发生部位形成层活动不均匀，次生木质部的导管口径缩小，数量减少，木纤维含量增多，由此向内形成缢缩。之后缢缩部位前端的细胞不断解体，使得缢缩不断加深，相邻的两个缢缩部位通常要延伸到劈裂发生部位的中心位置连接在一起，整个维管束裂成多个单独的维管束，并相互分离。 2．长叶红沙根、劈裂发生部位木质部中有异常的类似形成层的结构，木质部被几层扁平的细胞环分割成数轮，推测其与劈裂生长的发生密切相关。 3．内源激素在长叶红沙不同部位含量不同，尤其在刚刚开始劈裂的过渡植株的劈裂发生部位IAA和ZR的积累量比根部大，可能共同调节这个部位细胞的生长和分裂，促进劈裂生长的发生。4．对同一生境条件下进行劈裂生长的长叶红沙、红沙和无壁裂生长现象的半日花内源激素的研究发现，长叶红沙在刚刚开始劈裂的过渡植株的壁裂发生部位累积IAA和ZR，红沙在刚刚开始劈裂的过渡植株的壁裂发生部位累积GA：；和ZR，半日花则是幼苗茎基部的激素含量较高，说明内源激素在生长旺盛部位含量较高，对劈裂生长的发生具有一定的调控作用。5．对内蒙古西鄂尔多斯荒漠区强旱生小灌木抗氧化酶系统的研究发现，它们的膜脂过氧化程度都不高，但体内SOD、POD、CAT的活力表现不同，说明不同植物对于干旱的环境条件具有不同的适应机制。更多还原

【Abstract】 There are abundance of shrubs in Inner Mongolia West Erods region,which develop respective ways to adapt to the abominable conditions:drought,high temperature,sandy wind etc.Some of them have the same character-fissurate growth.In the study,we selected typical fissurate growth species living in the regionjleaumuria trigyna Maxim ,studied cell characters of fissurate growth .At the same time,we selected both fissurate growth species- Reaumuria trigyna Maxim, Reaumuria soongorical(Pall) Maxim and unfissurate growth species-Helianthemum soongoricum Schrenk ,studied the changes of the endogenous phytohormones content and the enzyme activity of the antioxidation system and wanted to know the physiological mechanism and adaptation of fissurate growth.The results are as follows:1 .Cell characters of fissurate growth in Reaumuria trigyna Maxim is very similar with that in potaninia mongolica. Fissurate growth starts from the base of stem.During certain phases of growth,the cambium layer of the fissurate part is asymmetric, the vessel of secondary xylem becomes smaller and less,while the amount of xylem fiber increases.The constriction forms here.Then the cells gradually disintegrate at the front of the constrition,the constrition gradually becomes deeper and splits here.One constrition will connect with the next one when they extend to the center of fissurate part.The whole vascular bundle splits into many single vascular bundles and they separate from each other.2.There is unnormal cambium layer structure in the fissurate place of Reaumuria trigyna Maxim. Xylem are divided into several rings by the several layers of flat cells. We think it can play a role in fissurate growth.3.The contents of endogenous phytohormones in the cells of different parts are different,especially in the fissurate place,the contents of IAA ,ZR are more than that in the root,which probably adjust the split of the cells in the place and accelerate the fissurate growth.4. The endogenous phytohormones of fissurate growth species-Reaumuria trigyna Maxim, Reaumuria soongorical(Pall) Maxim and unfissurate growth species-Helianthemum soongoricum Schrenk living in the same place was studied.The contents of IAA, ZR are higher in the fissurate place of Reaumuria trigyna Maxim; The contents of GA3, ZR are higher in the fissurate place in Reaumuria soongorical(Pall.) but the content of endogenous phytohormones are higher in seedling of Helianthemum soongoricum Schrenk ,which illuminates endogenous phytohormones are higher in the actively growing parts and probably adjust the fissurate growth.5. The enzyme activity of the antioxidation system of xermorphic shrubs in Inner Mongolia West Erods region was studied. The extent of lipid peroxidation is not higher, but SOD POD CAT activity is different in different vegetation,which illuminates different vegetation has different adaptive mechanism to the droughty environment.更多还原