Morphological and elemental evaluation of biochar through analytical techniques and its combined effect along with plant growth promoting rhizobacteria on Vicia faba L. under induced drought stress

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Interactive Effects of Plant Growth-Promoting Rhizobacteria and Phosphates Sources on Growth and Phosphorus Nutrition of Soybean under Moderate Drought

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha47311371 ◽

2019 ◽

Vol 47 (3) ◽

Author(s):

Vladimir Ion ROTARU ◽

Luxita RISNOVEANU

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Water Supply ◽

Nutrient Uptake ◽

Burkholderia Cepacia ◽

Plant Growth Promoting Rhizobacteria ◽

P Nutrition ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting

The growth of legume plants is usually improved by the rhizobacteria inoculation under low phosphorus (P) and alleviation of P nutrition plays important role in plant drought stress response. The aim of this study was to assess the comparative efficacy of two plant growth promoting rhizobacteria namely Burkholderia cepacia B36 and Enterobacter radicincitans D5/23T combined with two sources of phosphates in soybean (Glycine max L.) under low water supply. Plants were grown under P soluble versus insoluble P fertilization for comparing the effects of soybean inoculation on growth, uptake and use efficiency of phosphorus under moderate drought stress. At the beginning of flowering, half of plants was subjected to low water supply (35% water holding capacity, WHC) for 12 days while control plants were well watered - 70% WHC. The plants were harvested at the end of drought and physiological traits and P contents were analyzed. The inoculation treatments showed better plant growth and nutrient uptake when compared to uninoculated control. The application of the Burkholderia cepacia was more efficiently in terms plant growth than E. radicincitans especially under insoluble phosphates. Phosphorus concentrations of shoots and roots increased with both bacterial strains. The bacterial inoculation has much better stimulatory effect on nutrient uptake by soybean fertilized with insoluble phosphates. Study findings indicate that the combined application of PGPR (Burkholderia cepacia B36) and P amendments has the potential to improve P nutrition and growth of soybean cultivated on P-deficient soil under well-watered as well as moderate drought condition. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

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