Abstract

Plant growth-promoting rhizobacteria (PGPR) have been shown to reduce the negative effects of drought on numerous plant species, but these effects are unknown for common bean (Phaseolus vulgaris L.) crop. The study aimed to investigate the effects of inoculation with Rhizobium tropici, Azospirillum brasilense and the co-inoculation with both rhizobacteria on the nodulation, growth and tolerance of common bean plants to drought stress. Three water replenishment regimes [100% of pot capacity (non-stress control), 50% of pot capacity (moderate stress) and 25% of pot capacity (severe stress)] and four seed inoculation treatments: control (non-inoculated), inoculation with R. tropici, inoculation with A. brasilense; and co-inoculation with R. tropici and A. brasilense were studied in an experiment arranged in a 3 × 4 factorial scheme with four replicates. Relative water content (RWC), membrane stability index, nodulation, relative chlorophyll index, plant growth, and grain production were recorded. The inoculation of common bean plants with R. tropici and A. brasilense, and the co-inoculation improved leaf membrane stability and minimized the water loss from leaf tissue of plants under water stress conditions. Plants co-inoculated with R. tropici and A. brasilense had greater nodulation and relative chlorophyll index under severe drought stress. The inoculation with A. brasilense and the co-inoculation can attenuate the pod abortion rate of bean plants under moderate drought conditions but had no effect under severe stress conditions. Co-inoculation of A. brasilense and R. tropici alleviate the negative effects of water stress and maintain growth and grain yield of the common bean plants, and therefore, this management practice can be used by common bean farmers to enhance the plant tolerance to drought.

中文翻译：

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普通豆与根瘤菌和偶氮螺旋菌的共同接种可增强抗旱性

摘要

已经证明促进植物生长的根际细菌（PGPR）可以减少干旱对许多植物物种的负面影响，但是对于普通豆类（菜豆）而言，这些影响是未知的。该研究旨在研究接种热带根瘤菌，巴西固氮螺菌和同时接种两种根瘤菌对普通豆类植物的结瘤，生长和耐旱性的影响。三种补水方案[盆栽能力的100％（无压力控制），盆栽能力的50％（中等压力）和盆栽能力的25％（严重压力）]和四种种子接种处理：对照（​​未接种），接种R. tropici，接种A. brasilense; 并在3×4因子分解方案中进行了实验，研究了与R. tropici和A. brasilense的共接种情况，一式四份。记录相对水含量（RWC），膜稳定性指数，结瘤，相对叶绿素指数，植物生长和谷物产量。普通豆植物用热带稻和巴西农杆菌接种以及共同接种可改善叶片膜的稳定性，并使水分胁迫条件下植物叶片组织的水分流失最小化。在严重干旱胁迫下，与热带寄主和巴西寄主一起接种的植株具有更大的结瘤和相对叶绿素指数。巴西拟南芥的接种在中度干旱条件下，共接种可减轻豆类植物的荚果流产率，但在重度胁迫条件下则无作用。共同种植巴西芸苔和热带玫瑰减轻了水分胁迫的负面影响，并维持了普通豆类植物的生长和籽粒产量，因此，普通豆农可以采用这种管理方法来增强植物的抗旱性。