Effects of drought stress on vegetative growth and biochemical changes of six ornamental species in tropical

Drought is one of the environmental stresses, which have detrimental effects on most of plant growth stages, structure of organs and their activities. This experiment was conducted in 2014 to study the effects of drought stress on vegetative and biochemical changes of three six ornamental species include Ipomoea carnea, Delonix regia, Lantana camara, bougainvillea glabra, dodonaea viscose, clerodendron inerme. The experiment was performed with factorial based on a completely randomized design with 3 replications. Drought stress starteded by withholding irrigation and continued until plants wilted. Control pots were irrigated regulatory. Growth of the shoot, relative water content pigments concentrate (total chlorophyll, chlorophyll a, b and carotene) and proline was determined in control and treatments. According the results, drought stress significantly reduced vegetative growth of the most species that studied. Compared to other plant, the growth of dodonaea viscose was less affected. Leaf relative water content, and content of photosynthetic pigments (chlorophyll a, b and carotene) significantly reduced compared to control, in all species. Ipomoea carnea and dodonaea viscose showed the less chlorophyll difference rather than other. However proline increased dramatically in all plant species in response to drought stress. Royal Poinciana and Lantana camara showed the most increase in the amount of prolin. In general depending on the plant type, the response of plants to drought stress was different. Response of some species was reducing growth however in some plant chlorophyll content was reduce.