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Tibet University (2020)

Study on the Growth and Drought Resistance of Three Species of Hippophae in Tibet

南吉斌

Titre : Study on the Growth and Drought Resistance of Three Species of Hippophae in Tibet

Auteur : 南吉斌

Grade : Master 2020

Université : Tibet University

Résumé
In this study,the biennial seedlings of Hipopophae neurocarpa,H.rhamnoides subsp.yunnanensis,and H.gyantsensis distributed in Tibet were used as experimental materials to study the growth and photosynthetic characteristics of three species of Hippophae Difference ;The experiment of water control in pot was used to simulate the arid environment.The response mechanism of photosynthetic physiology and growth to water change of three species of Hippophae was studied systematically by comparing the photosynthetic index,chlorophyll fluorescence index,physiological and biochemical index and growth index of three species of Hippophae.The drought resistance of three species of Hippophae was evaluated by principal component analysis and membership function.The main results are as follows :(1)Comparison of growth of three species of Hippophae species:Logistic model is the best fitting equation for seedling height,ground diameter and growth time of three species of Hippophae species ;the annual growth trends of the three species of Hippophae species are consistent,and the overall growth rate is"S"type curve changes ;during the whole annual growth process,the seedling height and ground diameter of the three species of Hippophae were H.gyantsensis>H.rhamnoides subsp.yunnanensis>H.neurocarpa.(2)Photosynthetic physiological analysis of three species of Hippophae:the net photosynthetic rate(Pn)of three species of Hippophae increases first and then decreases with the increase of PAR and CO2concentration ;the daily changes of Pn,Tr,WUE and CE show a"single peak"trend,Gsshows a"V"type change,Cishows a"W"type change.The results show that:H.rhamnoides subsp.yunnanensis>H.gyantsensis>H.neurocarpa.(3)Photosynthetic physiology analysis of three species of Hippophae under different drought stress gradients:with the increase of drought stress time,Pn,Gs,Ci,Tr,ETR,YPSII,Fv′/Fm′of three species of Hippophae shows a downward trend ;WUE,CE and qpare significantly different among three species of Hippophae ;WUE,CE and qpof H.rhamnoides subsp.yunnanensis and H.neurocarpa show a downward trend with the increase of drought stress time ;WUE of H.gyantsensis shows an inverted"V"type change Chemical,CE and qpshowed"V"type changes.(4)Growth analysis of three species of Hippophae under different drought stress gradients:seedling height,ground diameter,root biomass,stem and leaf biomass,total biomass,main root length and number of primary lateral roots of three species of Hippophae decrease with the increase of drought stress time,and the specific leaf weight increase.(5)Physical and chemical analysis of three species of Hippophae under different drought stress gradients:the relative water content,leaf water potential and SPAD value of three species of Hippophae decrease with the increase of drought stress time,and the activities of water saturation deficit,malondialdehyde,proline and pod enzyme increase ;the reducing sugar of H.rhamnoides subsp.yunnanensis and H.gyantsensis show an inverted"V"type change,while that of costal H.neurocarpa shows a downward trend.(6)Comprehensive evaluation of resistance:27 indexes of 3 species of Hippophae are evaluated by membership function and principal component analysis.The results show that the drought resistance ability is in the order of:H.gyantsensis>H.neurocarpa>H.rhamnoides subsp.yunnanensis.

Mots clés : drought resistance ;growth;Hippophae ;Tibet;

Présentation (CNKI)

Page publiée le 8 novembre 2021