Soil applied vermicompost improves morpho-physio-biochemical and quality attributes of lettuce under saline conditions
Rehmana Juleel, Kamran Ashraf, Khawar Sultan, Gang Deng, Muzammal Rehman, Manzer H. Siddiqui, Qamar uz Zaman
Abstract
The salinity of agricultural soils has a profound effect on crop productivity. Humic chemicals present in vermicompost interact with the organic components of the soil and the plant's roots, and can dramatically affect the plant's response to salinity-induced stress. The purpose of the current study was to observe the effects of soil-applied vermicompost to minimize the detrimental effects of saline conditions. Therefore, this study was designed to evaluate the various vermicompost levels (0%, 2.5%, and 5.0%) on the growth, physio-biochemical, and antioxidant potential of lettuce when plants were grown under different salinity levels (75 and 150 mM using NaCl salt) and without salinity as the control in pots. The results indicated that salinity stress decreased the root length (24–51%), shoot length (21–49%), number of leaves (24–56%), root fresh weight (25–47%), shoot fresh weight (16–36%) and plant fresh weight (17–37%) under various levels of salinity stress by lowering relative water content (RWC) and chlorophyll concentrations due to increased electrolyte leakage (86–174%) and the sodium (Na+) contents in leaves, depending on the severity of the stress. However, vermicompost significantly enhanced the fresh and dry biomass at both salinity levels. Application of 5% vermicompost partly alleviates the effects of salinity on lettuce by up-regulating the antioxidant system, reducing lipid peroxidation, increasing leaf soluble sugars (30.11%), and simultaneously decreasing electrolyte leakage. In crux, the application of vermicompost (5%) activates physio-biochemical defense responses in lettuce plants against salt stress. Realizing that vermicompost plays a vital role in nutrient uptake opens up the possibility of increasing agricultural productivity and gives a good foundation for making plants more resistant to stress caused by salinity.