Alleviation of Associated Drought and Salinity Stress' Detrimental Impacts on an Eggplant Cultivar ('Bonica F1') by Adding Biochar

Abstract

To investigate the impact of biochar on eggplant growth, physiology, and yield parameters under separate and associated drought and salt stress, a pot experiment was carried out. An eggplant variety ('Bonica F1') was exposed to one NaCl concentration (S1 = 300 mM), three irrigation regimes (FI: full irrigation; DI: deficit irrigation; ARD: alternate root-zone drying irrigation), and one dose of biochar (B1 = 6% by weight). Our findings demonstrated that associated drought and salt stress had a greater negative impact on 'Bonica F1' performance in comparison to single drought or salt stress. Whereas, adding biochar to the soil improved the ability of 'Bonica F1' to alleviate the single and associated effects of salt and drought stress. Moreover, in comparison to DI under salinity, biochar addition in ARD significantly increased plant height, aerial biomass, fruit number per plant, and mean fresh weight per fruit by 18.4%, 39.7%, 37.5%, and 36.3%, respectively. Furthermore, under limited and saline irrigation, photosynthetic rate (A_n), transpiration rate (E), and stomatal conductance (g_s) declined. In addition, the interaction between ARD and biochar effectively restored the equilibrium between the plant chemical signal (ABA) and hydraulic signal (leaf water potential). As a result, mainly under salt stress, with ARD treatment, intrinsic water use efficiency (WUE_i) and yield traits were much higher than those in DI. Overall, biochar in combination with ARD could be an efficient approach for preserving crop productivity.

Keywords: Solanum melongena L.; biochar; drought; salt.

Figure 1

Photosynthetic rate (A_n) (a), transpiration rate (E) (b), stomatal conductance (g_s) (c), and intrinsic water use efficiency (WUE_i) (d) as influenced by biochar (B0 = 0% and B1 = 6%), irrigation regime (FI, DI, and ARD), and NaCl (S0 = 0 mM NaCl and S1 = 300 mM NaCl). Data are means of five replicates ± SE (n = 5). SE denotes standard error.

Figure 2

Water potential (ψ_l) (a) and concentration of abscisic acid (ABA) (b) of leaves of eggplant variety (‘Bonica F1’) as impacted by biochar doses (B0 = 0% and B1 = 6%), irrigation regimes (FI, DI, and ARD), and NaCl (S0 = 0 mM NaCl and S1 = 300 mM NaCl). Data are means of five replicates ± SE (n = 5). SE denotes standard error.

Figure 3

Leaf C (a), and N (b) concentration and leaf chlorophyll content index (c) as influenced by biochar (B0 = 0% and B1 = 6%), irrigation regime (FI, DI, and ARD), and NaCl (S0 = 0 mM NaCl and S1 = 300 mM NaCl). Data are means of five replicates ± SE (n = 5). SE denotes standard error.

Figure 3

Leaf C (a), and N (b) concentration and leaf chlorophyll content index (c) as influenced by biochar (B0 = 0% and B1 = 6%), irrigation regime (FI, DI, and ARD), and NaCl (S0 = 0 mM NaCl and S1 = 300 mM NaCl). Data are means of five replicates ± SE (n = 5). SE denotes standard error.

Figure 4

Leaf K⁺ (a) and Na⁺ (b) content as influenced by biochar (B0 = 0% and B1 = 6%), irrigation regime (FI, DI, and ARD), and NaCl (S0 = 0 mM NaCl and S1 = 300 mM NaCl). Data are means of five replicates ± SE (n = 5). SE denotes standard error.