Combined use of Enterobacter sp. MN17 and zeolite reverts the adverse effects of cadmium on growth, physiology and antioxidant activity of Brassica napus

Abstract

The objective of the study was to evaluate role of zeolite and Enterobacter sp. MN17 on Cd uptake, growth, physiological and biochemical responses of Brassica napus on Cd-contaminated soil. A sandy clay loam soil in plastic pots was spiked with Cd (0 and 80 mg kg-1) and amended with zeolite (0 and 10 g kg-1). Seeds of B. napus were inoculated with Enterobacter sp. MN17. Both inoculated and non-inoculated seeds of B. napus were sown and plants were harvested after 60 days of growth and data were collected. Although sole application of zeolite and seed inoculation reverted adverse effects of Cd in B. napus plants, the combined use resulted in even higher growth and physiological responses compared to control plants. The combined use under Cd stress increased plant height, root length, dry biomass of shoot and root up to 32%, 57%, 42% and 64%, respectively compared to control. The different physiological attributes (photosynthetic rate, chlorophyll content, transpiration rate, stomatal conductance) of B. napus were improved from 6% to 137%. Moreover, combined use of zeolite and seed inoculation on Cd-contaminated soil reduced the stress to plants as antioxidant activities decreased up to 25–64%, however enzyme activities were still higher than plants grown on normal soil. Root and shoot analysis of B. napus for Cd content depicted that zeolite and bacterium decreased Cd uptake from soil. It is concluded that combined use of zeolite and strain MN17 reduces Cd uptake from soil and improves physiological and biochemical responses of B. napus which is helpful to alleviate Cd toxicity to plants.

Alleviation of Salinity Induced Oxidative Stress in Chenopodium quinoa by Fe Biofortification and Biochar—Endophyte Interaction

“…UAF-Q7) were obtained from the Laboratory of Alternative Crops, Department of Crop Physiology, University of Agriculture, Faisalabad, Pakistan. Surface-disinfected seeds of quinoa were soaked in liquid suspension of PsJN (10 9 CFU mL −1 ) for one hour while un-inoculated seeds were dipped in broth without bacterial cells [31]. Six seeds were initially sown in polyethene lined pots containing 8 kg soil and after germination, two seedlings per pot (each representing one replicate) were maintained.…”

“…This improvement in growth of plants might be associated with solubilization of nutrients from biochar [51]. This might also be due to the role of biochar and applied bacteria that have resulted in rhizosphere acidification leading to desorption of nutrients from biochar surface and /or soil colloids and thus have stimulated the growth attributes [31,[51][52][53]. These observations are supported by previous studies, where siderophore producing bacteria including PsJN (which secrete hydroxamate-containing siderophore such as pyoverdin) often reported enhanced plant growth by facilitating Fe uptake and mediating plant tolerance against various abiotic stresses [13,54,55].…”

“…By virtue of its high cation exchange capacity, biochar might have increased the availability of essential nutrients to stressed plants and hence enhanced physiological adaptations of quinoa plants under stress [63]. Moreover, bacterial inoculation can have a positive effect on plant physiology through uplifting chlorophyll contents, stomatal conductance, internal CO 2 concentration and relative water contents [31,[64][65][66][67]. Certain PGPB have been recognized in imparting salinity resistance through direct stimulation of crops by providing fixed N, Fe sequestered by bacterial cells, phytohormones and soluble phosphates [11,68,69].…”

“…In current study, plants grown on saline soil showed significant reduction in nutritional parameters, however, the application of biochar and PsJN significantly improved nutritional attributes. This enhancement of nutritional status of amended plants might be due to the better provision of nutrients through biochar and endophytic bacteria [31,64] which might have helped plants to better adjust under unfavorable growth conditions [76].…”

Rice OsHSFA3 Gene Improves Drought Tolerance by Modulating Polyamine Biosynthesis Depending on Abscisic Acid and ROS Levels

“…Abiotic stresses such as drought, salinity and suboptimal temperature are serious threats for agriculture and global food security [1,2]. These stresses negatively affect plant growth and development and ultimately result in poor crop production [3][4][5]. Rice is a major grain crop and feeds about half of the world population [6,7].…”