The drought stress tolerance of several lawn-style roof-green species in Guangzhou Area

Eight plants of Crassulaceae and Commelinaceae were evaluated by measuring their morphological changes, soil water content, leaf relative water content, electrolyte osmotic rate, malonyldialdehyde (MDA) content, superoxide dismutase (SOD) activity and water soluble carbohydrate content under the simulated drought condition. The eight plants were Sedum lineare, Sedum alfredi, Sedum emarginatum, Sedum polytrichoides, Setcreasea purpurea, Tradescantia spathacea, Murdannia loriformis and Callisia repens. The physiological and biochemical indices performed differently after stress in which soil water content and leaf relative water content decreased, electrolyte osmotic rate, MDA content and water soluble carbohydrate content increased and SOD activity increased firstly and then decreased. The comprehensive evaluation using membership functions showed that the order of drought resistance from strong to weak was Callisia repens＞Sedum lineare＞Sedum polytrichoides＞Tradescantia spathacea＞Sedum alfredi＞Setcreasea purpurea＞Sedum emarginatum＞Murdannia loriformis. The plants had little changes after 14 days water stress and can restore after 35 days water stress when it regained watering which suggested that the plants could be used as lawn-style roof greening materials in Guangzhou area.