The Effect of Humic Acid Applications on Some Morphological, Physiological and Biochemical Characteristics of Eggplants Irrigated with Water Contained Heavy Metals in High Concentration

Abstract

In this study, it was aimed to demonstrate the effect of humic acid applications on some morphological, physiological and biochemical characteristics of eggplant genotypes (Burdur Merkez, Burdur Bucak, Kemer and Giresun) irrigated with the irrigation water with a high content of heavy metal and determined previously salt tolerance levels. In studies conducted in controlled greenhouse conditions, eggplant seeds germinated in the growth substrate a mixture of peat and perlite and the seedlings were transplanted into pots at 20 days after sowing. Plants when they are 4-5 true leaves, 3 different humic acid levels (0, 500, 1000 ppm) have been applied and 7 days later after this application began to be watered with 3 different irrigation water comprising a mixture of various doses of heavy metals (control: 0 ppm; I. Mixture: 0.2 ppm 5 ppm to 0.01 ppm Cd + Cu + Pb + 2 ppm Zn, II. mixture: +0.02 ppm 0.4 ppm Cu 10 ppm Pb + Cd + 4 ppm Zn). Field capacity level for the plants 40 days after quenched with water after which time they were harvested and samples for analysis were performed. In the study plants were investigated for shoot and root fresh weight, shoot and root dry weight, shoot and root length, leaf area, chlorophyll and MDA level of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) enzyme activities All genotypes are adversely affected by heavy metal applications. In parallel to increase the dose, heavy metal mixtures led to a reduction in values of fresh and dry weight of shoot and root, stem and root length, leaf area of eggplant genotypes. MDA and antioxidative enzyme activities increased in plants irrigated with water containing a mixture of heavy metal. Humic acid applications had a positive effect on reducing of the limiting effect of heavy metal stress on growth and development. As a result, compared to sensitive genotypes Giresun and Kemer, salt tolerant genotypes Burdur Merkez and Burdur Bucak showed much better resistance to abiotic stress factor which consists of heavy metal applications. The obtained results; formed also an opinion about that plants evolved similar strategies for resistance to abiotic stresses such as salinity, drought and heavy metal stress.