Mixing tannery effluent had fertilizing effect on growth, nutrient accumulation, and photosynthetic capacity of some cucurbitaceous vegetables: A little help from foe

Biological roles of soil microbial consortium on promoting safe crop production in heavy metal(loid) contaminated soil: A systematic review

Heavy metal(loid) (HM) pollution of agricultural soils is a growing global environmental concern that affects planetary health. Numerous studies have shown that soil microbial consortia can inhibit the accumulation of HMs in crops. However, our current understanding of the effects and mechanisms of inhibition is fragmented. In this review, we summarise extant studies and knowledge to provide a comprehensive view of HM toxicity on crop growth and development at the biological, cellular and the molecular levels. In a meta-analysis, we find that microbial consortia can improve crop resistance and reduce HM uptake, which in turn promotes healthy crop growth, demonstrating that microbial consortia are more effective than single microorganisms. We then review three main mechanisms by which microbial consortia reduce the toxicity of HMs to crops and inhibit HMs accumulation in crops: 1) reducing the bioavailability of HMs in soil (e.g. biosorption, bioaccumulation and biotransformation); 2) improving crop resistance to HMs (e.g. facilitating the absorption of nutrients); and 3) synergistic effects between microorganisms. Finally, we discuss the prospects of microbial consortium applications in simultaneous crop safety production and soil remediation, indicating that they play a key role in sustainable agricultural development, and conclude by identifying research challenges and future directions for the microbial consortium to promote safe crop production.

In vitro silicon supplementation enhanced acclimatisation and growth of sugarcane (Saccharum officinarum) via improved antioxidant and nutrient acquisition patterns in saline soil

Salinity affects crop growth by modulating cellular ionic concentrations and generation of reactive oxygen species. Application of silicon (Si) has proved beneficial in ameliorating salinity-triggered plant growth and yield retardations. Leaf roll explants of three sugarcane (Saccharum officinarum ) genotypes (HSF-240, CPF-246, CPF-250) were cultured in Murashige and Skoog (MS) medium supplemented with K2 SiO3 . In vitro regenerated plantlets were acclimatised and grown in natural saline soil. In absence of Si, cv. CPF-246 exhibited better salt tolerance as indicted by maximum chlorophyll a and chlorophyll b contents, rate of photosynthesis and root K+ uptake along with less cellular hydrogen peroxide content. Silicon restricted root Na+ uptake but assisted in K+ , Ca2+ , Mg2+ and Fe2+ accretion in roots and their translocation towards shoots. Cv. HSF-240 and cv. CPF-250 exhibited more increase in photosynthetic pigment content, stomatal conductance and photosynthetic rate after addition of 25 or 50mgL-1 Si than control group. Optimum phenolic content and antioxidant enzyme activity along with decreased lipid peroxidation and hydrogen peroxide content were recorded in all three sugarcane genotypes raised in presence of 25 or 50mgL-1 Si. These findings signify Si supplementation (50mgL-1 ) in tissue culture medium and plant adaptation in saline soil. Further in vitro studies involving Si-mediated gene expression modulations in sugarcane protoplasts shall assist in deciphering cross-talk between Si uptake and cellular responses. The application of Si can further be tested for other plant species to devise strategies for improved crop growth and utilisation of saline areas for crop cultivation.