Brassinosteroide analogue effect on lettuce grown at different moisture levels

Abstract: Water deficit is one of the most adverse factors for plant growth and productivity. The experiments were conducted to investigate the influence of synthetic brassinolide analogue at concentrations 100 nmol.L^-1 , 1 nmol.L^-1 , 0.01 nmol.L^-1 and 0 nmol.L^-1 on lettce seedling grown at two moisture levels (reduced, control). The plants were cultivated in growth chamber under day / night temperature of 20 oC/15 oC. The total quantities of irrigation water during the experiment: reduced - 28 mm; control - 39 mm. The seedlings of two butter head lettuce cultivars (cv. Mars and cv. Marsalus) were sprayed to foliage at juvenile stage of growth. The plant parameters (length, fresh weight of shoots and roots) and dry matter content were measured on 21^st and 28^th day after sowing. Significantly higher values of the average fresh weight and length of aboveground part and roots were measured on 28^th day for the cultivar Marsalus treated with brassinosteroide analogue at concentration 1 nmol.L^-1 in conditions with reduced irrigation. The results showed that treatment of plants in the initial stage of the development with 1 nmol.L^-1 solution can be used to limit the consequences of reduced moisture conditions. Prior to use the most effective concentration should be taken into account which parameter of plant is expected to be changed and also the varying sensitivity of the cultivars to the treatment.