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Northwest University of Science and Technology (2010)

Drought Resistant Physiological Basis of Six Xerophilous Shroubs

韩刚;Han Gang

Titre : Drought Resistant Physiological Basis of Six Xerophilous Shroubs

Auteur : 韩刚;Han Gang

Grade : Doctoral Dissertation 2010

Université : Northwest University of Science and Technology

Résumé partiel
In this paper, by using potted-seedlings and weighing method to control soil moisture the water parameters from pressure-volume curves, important osmotic adjustment substances, antioxidation protection system and light response characteristics of six xerophilous shrubs with high utilization value in arid and semiarid areas, Caragana korshinskii, Atraphaxis bracteata, Hedysarum mongolicum, Hedysarum Scoparium, Buddleja alternifolia and Atriplex canescens were studied under suitable soil moisture, medium drought and severe drought. Some important physiological responses to drought stress were explored in order to get some important physiological adaptive mechanism of six xerophilous shrubs to drought. And also selection methods of representative indexes about leaf anatomical structures of six xerophilous shrubs were explored ; the drought resistances of six xerophilous shrubs based on leaf anatomical structure were evaluated comprehensively. The main results were as follows:1. Compared to control of suitable soil moisture, as the drought stress degree was enhanced from medium to severe level, the water parameters from pressure-volume curvesψtlp、ψssat、RWCtlp and ROWCtlp of six shrubs showed a trend of decrease, while the value of Va showed a trend of increase. It indicated the abilities of maintaining turgor and capturing and keeping water of six shrubs were improved obviously.2. Based on seven water parameters from pressure-volume, the comprehensive estimating results on abilities of turgor maintaining showed that they were Hedysarum Scoparium> Caragana korshinskii> Hedysarum mongolicum> Atraphaxis bracteata> Atriplex canescens> Buddleja alternifolia under medium drought stress and Caragana korshinskii> Atraphaxis bracteata> Hedysarum Scoparium> Hedysarum mongolicum> Atriplex canescens> Buddleja alternifolia under severe drought stress.3. Under drought stress, K+ is a kind of substance that didn’t have the common osmotic adjustment action in the six xerophilous shrubs, while soluble sugar、proline、betaine and soluble protein had a common osmotic adjustment action. Under the different drought stress degrees, the kinds of substance taking part in the osmotic adjustment were different for the six xerophilous shrubs.4. For the six xerophilous shrubs, the cumulants of osmotic adjustment substances were affected by both drought stress degree and drought stress period. The changes of the cumulants of osmotic adjustment substances decided the osmotic adjustment abilities depending on them. Therefor, the osmotic adjustment abilities of six shrubs were in a dynamic changing condition.5. Under drought stress, the response models of antioxidation protection system of six xerophilous shrubs were closely related to drought stress degrees, drought stress periods and tree characteristics, and therefore showed some speciality, diversity, dynamic and complexity.6. For the six xerophilous shrubs, the cooperation between SOD and CAT and the cooperation among ASA、GSH、GR and APX in antioxidation protection system could be kept well or enhanced in the prophase and metaphase of medium and severe drought stress, but be weakened in the anaphase of drought stress, at this time the main method to Scavenging H2O2 in the chloroplast was usually direct Scavenging of ASA or GSH. In the long period of mederate and severy drought stresses, all the six xerophilous shrubs were poisoned by active oxygen, oxidative damage was inevitable and happened earlier with the enhance of drought stress degree

Mots clés : arid and semiarid areas; drought stress; xerophilous shrub; drought-resistant physiology; drought resistance;

Présentation (CNKI)

Page publiée le 3 mai 2013, mise à jour le 2 mai 2018