Impact of Different Salt-stressed Conditions on Growth, Mineral Nutrition and Fruiting of Bael (Aegle marmelos) Cultivars

Abstract

Bael (Aegle marmelos) cultivars (NB-5, NB-9, CB-1 and CB-2) grown in normal (ECe 1.3 dS m-1) and saline soils (ECe 6.5 and 10.7 dS m-1) exhibited initial signs of salt injury as yellowing and scorching of leaves followed by leaf necrosis, abscission and wilting of plants. After 24 months of exposure to 6.5 dS m-1 salinity, the minimum (9.5%) and the maximum (58%) decreases in plant height were noted in NB-5 and CB-2 cultivars, respectively. High salinity (10.7 dS m-1) severely suppressed growth in all the cultivars, and NB-9 and CB-2 plants did not survive. Data on ion partitioning indicated restricted uptake of Na+ ions by NB-5 plants at moderate salinity. At high salinity, however, Na+ accumulation significantly increased in leaves and stems indicating soil saturation extract salinity (ECe) tolerance threshold limit of 6.0-7.0 dS m-1 in this cultivar. All the tested cultivars except CB-2 produced fruits in moderately saline soils with average number of fruits per plant being 2 in NB-5 and 0.67 in each NB-9 and CB-1 cultivars. However, fruit yield contributing traits like fruit length, breadth and weight significantly declined in salinized plants regardless of the cultivar. Salt stressed NB-5 plants not only prevented the accumulation of Na+ to toxic levels but also exhibited higher K+ concentrations in different parts resulting in better growth in saline soils.