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Northeast Normal University (2021)

Photosynthetic Physiology and Growth Adaptation Strategies of Plants with Different Photosynthetic Types to Drought-Rewatering

孙明伟

Titre : Photosynthetic Physiology and Growth Adaptation Strategies of Plants with Different Photosynthetic Types to Drought-Rewatering

Auteur : 孙明伟

Grade : Master 2021

Université : Northeast Normal University

Résumé partiel
Under the background of global climate change,drought has become a global environmental problem.Drought could affect plant growth either directly by limiting the physiological metabolism,such as photosynthesis and respiration,it also restricts nutrient uptake and indirectly changes plant morphological characteristics.As an important physiological process of plants,plants can be divided into C3 plants and C4plants according to the different photosynthetic pathways.At present,the understanding of the relationship between photosynthetic physiological responses of different photosynthetic types of plants and their morphological characteristics in the process of drought-rewatering is still relatively poor,and most of the studies involve fewer species and do not represent functional groups.In this study,we conducted a pot experiment using seven widespread annual C3 and C4 plants,and their photosynthetic physiological responses and morphological responses under the influence of different intensities of drought-rewatering were measured to answer the following scientific questions :(1)Are there any function group differences of photosynthetic physiological response and limiting factors(stomatal limitation and metabolic limitation)between C3 and C4 plants almong drought gradient ;(2)If the recovery of photosynthetic rate after rewatering depends on the intensity of drought treatment,and are there any functional group differences between C3 and C4 plants ;(3)What are similarities and differences of the growth adaptation strategies for precipitation variation between C3 and C4 plants.The main results of this study are as following :(1)Over all,both net photosynthetic rate(A)and stomatal conductance(gs)of all experimental species was significantly decreased under drought stress,whereas water use efficiency(WUE)was significantly increased.Although C3 plants had greater gs,its A and WUE was lower than C4 plants.The photosynthetic drought sensivity of C3plants were greater than C4 plants.Such as,under severe drought treatment,the A of C3 and C4 plants decrease by 21.6%and 49.5%,respectively.In moderate and severe drought treatment,the photosynthesis of C3 plants was controlled by relative stomatal limitation(RSL),but C4 plants was controlled by relative metabolic limitation(RML).(2)The drought sensitivity of C3 plant biomass was higher than that of C4 plants.Under moderate and severe drought treatment,the biomass of C3 plants decreased by19.6%and 40.3%,and that of C4 plants decreased by 7.5%and 21%.Drought significantly increased the root-shoot ratio(R/S ratio),leaf dry mass per area(LMA)and leaf nitrogen content per unit area(Narea).The R/S ratio of C3 plant increased by7.3%in moderate drought treatment,which was lower than 16%of C4 plant.The R/S ratio of C3 plant increased by 55.1%in severe drought treatment,which was higher than 37.7%of C4 plant.In addition,the response rate of LMA and Narea of C3 plants to drought was higher in both moderate and severe drought treatment.(3)The A of C4 plants recovered more slowly than that of C3 plants.After rewatering,the net photosynthetic rate of C3plants,except for Triticosecale wittmack and Avena sativa,recovered for one week,while C4 need two weeks.After rewatering treatment,the recovery of biomass of C4 plants was higher than that of C3 plants

Mots clés : C3 plant ;C4 plant ;drought-rewatering ;photosynthetic limitation ;root-shoot ratio ;leaf dry mass per area ;

Présentation (CNKI)

Page publiée le 2 novembre 2021