Cadmium is acute toxicity inducing heavy metal that significantly decreases the yield of crops. Due to high water solubility, it reaches the plant tissue and disturbs the uptake of macronutrients. Low uptake of nutrients in the presence of cadmium is a well-documented fact due to its antagonistic relationship with those nutrients, i.e., potassium. Furthermore, cadmium stressed plant produced a higher amount of endogenous stress ethylene, which induced negative effects on yield. However, inoculation of 1-amino cyclopropane-1-carboxylate deaminase (ACCD), producing plant growth promoting rhizobacteria (PGPR), can catabolize this stress ethylene and immobilized heavy metals to mitigate cadmium adverse effects. We conducted a study to examine the influence of ACCD PGPR on nutrients uptake and yield of bitter gourd under cadmium toxicity. Cadmium tolerant PGPRs, i.e., Stenotrophomonas maltophilia and Agrobacterium fabrum were inoculated solely and in combination with recommended nitrogen, phosphorus, and potassium fertilizers (RNPKF) applied under different concentration of soil cadmium (2 and 5 mg kg⁻¹ soil). Results showed that A. fabrum with RNPKF showed significant positive response towards an increase in the number of bitter gourds per plant (34% and 68%), fruit length (19% and 29%), bitter gourd yield (26.5% and 21.1%), N (48% and 56%), and K (72% and 55%) concentration from the control at different concentrations of soil cadmium (2 and 5 mg kg⁻¹ soil), respectively. In conclusion, we suggest that A. fabrum with RNPKF can more efficaciously enhance N, K, and yield of bitter gourd under cadmium toxicity.

Background: Waste-land weeds present around the fields exert their allelopathic influence on crops through their leaf leachates and rhizospheric soils. Objective: A study was conducted to investigate the phytotoxic action of four common waste-land weeds Parthenium hysterophorus L., Achyranthes aspera L., Lantana camara L. and Withania somnifera L. through their aqueous extracts and rhizospheric soils against winter crops Avena sativa L., Cicer arietinum L., Hordeum vulgare L. and Triticum aestivum L. Methods: Experiments were conducted in Agronomy laboratory in College of Agriculture at the University of Sargodha. In first experiment, 5% (w/v) water extract from entire plant of each weed was applied to germinating seeds of crops whereas in second experiment, crop seeds were subjected to the rhizospheric soil of each weed for germination test. Results: Results revealed that aqueous extracts of weeds were more phyto-inhibitory compared to their rhizospheric soils. Minimum germination percentage (42.5%), germination index (7.4), seedling vigor index (665.3), root length (3.27 cm), seedling length (14.15 cm) and seedling biomass (74.2 mg) of crops were recorded in response to aqueous extract of P. hysterophorus. Root growth of the crops was affected more compared to the shoot growth. Minimum germination percentage was observed in A. sativa (13.3) by the action of L. camara aqueous extract. Rhizospheric soil of L. camara and P. hysterophorus resulted in minimum germination percentages (57.5 and 58.3, respectively) and seedling vigor indices (1472.5 and 2008.4, respectively) of crops. The lowest germination (30%) and germination index (3.7) was observed for T. aestivum seeds germinated in the rhizospheric soil of W. somnifera. Among crops, A. sativa and C. arietinum were more susceptible to the aqueous extracts whereas T. aestivum to rhizospheric soils of weeds. Conclusions: It can be concluded that waste-land weeds especially P. hysterophorus and L. camara negatively affect the crops by their allelopathy.