IMPACT OF BIOCHAR AMENDMENT ON THE TO GROWTH, ANTIOXIDANT ACTIVITY AND HORMONES OF COMMON BEAN SEEDLINGS SUBJECTED TO SALINITY STRESS

3. Uluslararası Tarım, Çevre ve Sağlık Kongresi, 12 - 14 Kasım 2020

Salt stress is raported to be one of the the important agricultural problems limitings crop production,

especially in arid and semi-arid regions. Even at relatively low levels of its is known that significantly

reduced yield of common bean (Phaseolus vulgaris L.) which a salt-sensitive glycophyte. Biochar is

attracting increasing attention in recent years as a potential soil amendment under stress condition. Used

biochar in the study was produced by the thermal conversion process of 60% sewage sludge and 40%

household waste such as biological solids and green waste. In this study, the growth, physiological, and

biochemical responses of common bean grown in two salinity levels (0, and 75 mM NaCl) at three

biochar ratios (0, 2,5 and 5 %) were investigated in a conducted pot experiment in a climate‐controlled

greenhouse. All of the examined growth characters of bean were decreased at salt stress treatments. The

results indicated that salinity increased the activity of catalase (CAT), peroxidase (POD), and superoxide

dismutase (SOD), the content of malondialdehyde (MDA), hydrogen peroxide (H2O2), proline, and

sucrose, and the concentration of abscisic acid (ABA) in leaf compared to control. Additionally,

membrane stability index (MSI) increased by salinity compared to the non-saline treatment. However,

concentration of indole-3-acetic acid (IAA), jasmonic acid (JA), salicylic acid (SA), cytokinin (CK),

and gibberellic acid (GA) in leaf and the all growth components was decreased by salinity compared to

the non-saline treatment. In contrast, biochar applied to soil enhanced the all growth components

excluding stem diameter in comparison with the non-biochar treatment. On the other hand, it was

observed that to increases of IAA, JA, SA, CK, and GA concentrations, to decrease H2O2, proline, and

sucrose contents and ABA concentration in plants treated by biochar. As a result, the effectiveness of

2,5 % biochar was superior to the 5% treatment in terms of evaluated parameters, especially under saline

conditions. The produced results supported the idea that biochar can contribute to protecting common

bean against NaCl stress by reduction of endogenous stress hormones, the improvement of growth

hormones, and alleviation of oxidative stress.