Plant Physiology and Biochemistry ( IF 6.5 ) Pub Date : 2020-06-13 , DOI: 10.1016/j.plaphy.2020.06.017 José Ramón Acosta-Motos 1 , Shane A Rothwell 2 , Margaret J Massam 2 , Alfonso Albacete 3 , Hao Zhang 2 , Ian C Dodd 2
Sustainable approaches to rice cultivation that apply less irrigation and chemical fertilisers are required to increase crop resource use efficiency. Although alternate wetting and drying (AWD) has been widely promoted as a water-saving irrigation technique, its interactions with phosphorus (P) nutrition have attracted little attention. Vegetative rice plants were grown with two phosphorus levels, fertilised (HP) or un-fertilised (LP), and either continuous flooding (CF) or AWD irrigation. Treatment effects on substrate P bioavailability (measured by Diffusive Gradients in Thin films – DGT-P), plant and substrate water relations, and foliar phytohormone status, were assessed along with P partitioning in planta. Shoot biomass and leaf area under different irrigation treatments depended on substrate P status (significant P x irrigation interaction), since LP decreased these variables under CF, but had no significant effect on plants grown under AWD. AWD maintained DGT-P concentrations and increased maximal root length, but decreased root P concentrations and P offtake. Substrate drying decreased stomatal conductance (gs) and leaf water potential (Ψleaf) but re-flooding increased gs. AWD increased foliar abscisic acid (ABA), isopentenyl adenine (iP) and 1-aminocyclopropane-1-carboxylic acid (ACC) concentrations, but decreased trans-zeatin (tZ) and gibberellin A1 (GA1) concentrations. Low P increased ACC and jasmonic acid (JA) concentrations but decreased gibberellin A4 (GA4) concentrations. Across all treatments, stomatal conductance was negatively correlated with foliar ABA concentration but positively correlated with GA1 concentration. Changes in shoot phytohormone concentrations were associated with increased water and phosphorus use efficiency (WUE and PUE) of vegetative rice plants grown under AWD.
中文翻译:
交替进行的干湿灌溉增加了水和磷的利用效率,而与营养水稻植物的底物磷状况无关。
为了减少作物资源利用效率,需要减少灌溉和化学肥料的可持续水稻种植方法。尽管作为一种节水灌溉技术,交替湿润和干燥(AWD)已得到广泛推广,但其与磷(P)营养的相互作用却很少引起关注。营养水稻种植时需施以两种磷水平:施肥(HP)或未施肥(LP),并进行连续灌溉(CF)或AWD灌溉。评估了处理对底物P生物利用度的影响(通过薄膜中的扩散梯度– DGT-P测量),植物和底物的水分关系以及叶中植物激素状态,以及植物体内P的分配。不同灌溉处理下的枝条生物量和叶面积取决于基质P的状态(显着的P x灌溉相互作用),因为LP在CF下降低了这些变量,但对AWD下生长的植物没有显着影响。AWD维持DGT-P浓度并增加最大根长,但降低根P浓度和P吸收。基质干燥会降低气孔导度(g s)和叶片水势(Ψ叶片),但再次淹水会增加g s。AWD增加叶面脱落酸(ABA),异戊烯腺嘌呤(iP)和1-氨基环丙烷-1-羧酸(ACC)的浓度,但反式降低-玉米素(tZ)和赤霉素A1(GA1)浓度。低磷会增加ACC和茉莉酸(JA)的浓度,但会降低赤霉素A4(GA4)的浓度。在所有治疗中,气孔导度与叶面ABA浓度呈负相关,而与GA1浓度呈正相关。茎秆植物激素浓度的变化与在AWD条件下生长的营养水稻植物的水分和磷利用效率(WUE和PUE)增加相关。