Drought stress responses in seedlings of three multipurpose agroforestry trees species of central India

The effect of moisture on seedling growth of Albizia lebbeck (L) Benth., Leucaena leucocephala Lam. and Dalbergia sissoo Roxb. was evaluated in central India during 2018. One month old seedlings raised in polyethylene bags containing about 3 kg of garden soil were subjected to three watering frequencies as irrigating daily (control), and withholding irrigation upto 14 days (intermediate stress) and 21 days (severe stress). Observations were made according to different watering frequencies on eight quantitative traits viz. plant height, root length, survival percentage, relative water content, excised leaf water loss, total chlorophyll content, proline content and total biomass. All the traits considered were significantly decreased as stress increased. Under optimum moisture condition A. lebbeck and L. leucocephala performed well than D. sissoo. At intermediate stress D. sissoo had maximum reduction of 81.36%, 54.33%, 43.62% and 20.0% for traits like total biomass, root length, total chlorophyll content and survival percent, respectively. In severe stress condition also the pattern was similar as D. sissoo had maximum reduction for total biomass (84.75%), root length (63.77%), total chlorophyll content (46.30%) and survival percent (40.0%). While L. leucocephala had higher reduction for plant height by 26.46% and 40.03% at intermediate stress and severe stress, respectively and it also had higher reduction for total biomass (84.92%) at severe stress. In contrast, A. lebbeck had minimum reduction for the traits like total biomass (60.87%), root length (25.94%), survival percent (no reduction), total chlorophyll content (17.38%) and plant height (17.37%) at intermediate stress. Also the reduction pattern was similar at severe stress for total biomass (63.77%), root length (38.03%), survival percent (no reduction), plant height (32.79%) and total chlorophyll content (27.02%). In both stress levels, A. lebbeck had higher relative water content, proline accumulation and lower excised leaf water loss than L. leucocephala> D. sissoo. Based on physiological and biochemical trait expressions and minimum percent reduction for putative traits the species A. lebbeck indicated better drought resistance as compared with L. leucocephala > D. sissoo. Hence, A. lebbeck can be a choice of species for better agroforestry programmes in drought thriving arid and semi-arid regions.