Soil water availability and capacity of nitrogen accumulation influence variations of intrinsic water use efficiency in rice

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• 作者：Wei Xue^a ; ^b ; ^{xuewei8341@yeah.net" class="auth_mail" title="E-mail the corresponding author} ; Bhone Nay-Htoon^c ; Steve Lindner^a ; Maren Dubbert^c ; ^e ; Dennis Otieno^a ; Jonghan Ko^d ; Christiane Werner^c ; ^e ; John Tenhunen^a
• 关键词：Amax ; maximum assimilation rate ; Ci ; intercellular CO2 concentration ; Cs ; CO2 concentration at leaf surface ; Cc ; CO2 concentration at sites of carboxylation ; DAS ; day after transplanting ; DOY ; day of year ; gsc ; stomatal conductance ; gm ; mesophyll conductance ; Jmax ; maximum electron transport rate ; k ; plant hydraulic conductance ; LMA ; leaf mass per area ; PAR ; photosynthetically active radiation ; Nm ; leaf nitrogen content ; Rdark ; dark respiration ; SWC ; soil water content ; Vcmax ; maximum carboxylat
• 刊名：Journal of Plant Physiology
• 出版年：2016
• 出版时间：1 April 2016
• 年：2016
• 卷：193
• 期：Complete
• 页码：26-36
• 全文大小：2038 K

文摘

Leaf intrinsic water use efficiency (WUE_i) coupling maximum assimilation rate (A_max) and transpirable water lost via stomatal conductance (g_sc) has been gaining increasing concern in sustainable crop production. Factors that influence leaf A_max and WUE_i in rice (Oryza sativa L. cv Unkang) at flooding and rainfed conditions were evaluated. Positive correlations for leaf nitrogen content (N_m) and maximum carboxylation rate (V_cmax), for nitrogen allocation in Rubisco enzymes and mesophyll conductance (g_m) were evident independent of cropping cultures. Rainfed rice exhibited enriched canopy leaf average N_m resulting in higher A_max, partially supporting improved leaf WUE_i. Maximum WUE_i (up to 0.14 μmol mmol⁻¹) recorded in rainfed rice under drought conditions resulted from increasing g_m/g_sc ratio while at cost of significant decline in A_max due to hydraulically constrained g_sc. A_max sensitivity related to g_sc which was regulated by plant hydraulic conductance. WUE_i was tightly correlated to V_cmax/g_sc and g_m/g_sc ratios across the paddy and rainfed not to light environment, morphological and physiological traits, highlighting enhance capacity of N_m accumulation in rainfed rice with g_sc at moderately high level similar to paddy rice facilitate optimization in A_max and WUE_i while, is challenged by drought-vulnerable plant hydraulic conductance.