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Chinese Academy of Agricultural Science (2021)

Physiological and Biochemical Mechanisms for Water,Nitrogen and Elevated CO2 Impact on Barley and Oats

李丽

Titre : Physiological and Biochemical Mechanisms for Water,Nitrogen and Elevated CO2 Impact on Barley and Oats

Auteur : 李丽

Grade : Doctoral Dissertation 2021

Université : Chinese Academy of Agricultural Science

Résumé partiel
Soil drought is often accompanied by low soil nitrogen(N)use efficiency,and reasonable water and N management is important to improve crop water and N use efficiency.Stomata regulate the exchange of gases between plants and atmosphere,and they are important in controlling the two physiological processes of photosynthesis and transpiration.Therefore,exploring the regulatory mechanism of stomatal movement is of great significance to understand the response of crops to environmental stress.In recent years,the atmospheric CO2 concentration has been increasing.Under the condition of climate change in the future,how to manage water and fertilizer reasonably will be a new problem and challenge in agricultural production.Therefore,in the present study,oat and barley(WT and its correspondent ABA-deficient mutant barley Az34)were used as plant materials,and 15 N,13C,18 O isotope techniques were used to analyze the phenotypic and physiological/biochemical changes of oat under drought and N deficiency stress ;the ion fluxes of barley mesophyll/ guard cells were measured by noninvasive micro-test technology(NMT)to quantitatively record and the transmembrane movement of ions,and the mechanisms of phenotypic changes were explored in subcellular and molecular levels combining with the proteomic analysis of leaves ;the physiological response of barley to N-fertigation and its behind physiological mechanisms were studied at elevated CO2,and the quality attributes of barley seeds were analyzed,which would provide theoretical basis for achieving water-saving,fertilizer-saving,high-quality and high-yield agriculture under elevated atmospheric CO2 concentration and water shortage in the future.The main results are outlined as follows :(1)Moderate drought stress(50% of soil water holding capacity)or high N supply(298 mg/kg N)significantly reduced stomatal conductance,water consumption and increased water use efficiency(WUE)at stomatal and plant levels.Under drought stress or high N treatment,the partial stomatal closure had no significant effect on photosynthetic rate.Although the shoot dry biomass decreased by6.7% or even significantly reduced by 21.3% in the mildly(70% of soil water holding capacity)and moderately drought-stressed treatments,plant water use efficiency(WUEb)of oat plants in these two water deficit treatments increased by 10.8% and 7.4%,respectively,as compared with the well-watered(90% of soil water holding capacity)plants.Moderate drought stress or high N treatment increased shoot carbon isotope composition(δ13C).At the same time,the positive correlation between δ13C and oxygen isotope composition(δ18O)indicated that the improvement of WUE at stomatal and plant levels under the reduced soil water contents or high N treatment were mainly attributed to the reduction of stomatal conductance.(2)Leaf ABA concentration([ABA]leaf)of both genotypes increased significantly and WT had a higher [ABA]leaf than Az34 at 2 hours after exposure to 10% polyethylene glycol(PEG)6000.[ABA]leaf of WT was significantly greater compared to that of the control plants while this was not the case for Az34 on 9 d after PEG treatment.

Mots clés : The interaction between drought stress and N deficiency ;Elevated CO2 ;Physiological mechanism ;Yield;

Présentation (CNKI)

Page publiée le 16 novembre 2021