Effect of limited irrigation on growth and water use of Jatropha curcas L.

摘要

A pot-grown experiment was conducted to investigate the effect of limited irrigation on growth, storage water amount of every organ and water use of Jatropha curcas L.seedlings. Four watering treatments were designed in the study, i.e. (W1: 0.3θ_f, W2: 0.5θ_f, W3: 0.7θ_f, W4: 0.9θ_f, θf is the field capacity). Results show that Jatropha curcas L.seedlings has the higher resistance ability to drought-stress, it can survival in lower soil moisture (0.3θf), and has certain growth potential. Dry mass of every organ in plant shows that shoot＞branch and master rod ＞leaf＞ root ＞ petiole. Storage water capability of unit dry mass for every organ in plant shows that petiole＞branch and master rod or shoot＞leaf＞root. Compared to W4 treatments, W2 reduced irrigation water by 27.1%, mean leaf area of Jatropha curcas L.seedlings for W2 reduced by 25.8%, but root-shoot ratio increased by 6.1%, meanwhile, mean storage water capability of unit root, lateral branch and master rod, leaf, shoot and total plant dry mass of Jatropha curcas L.seedlings for W2 increased by 15.4%, 1.3%, 7.4%, 0.6% and 1.8%, respectively. But mean root, shoot and total plant dry mass accumulation of Jatropha curcas L.seedlings for W2 only reduced by 11.4%, 17.7%, 15.8%, respectively, therefore, irrigation water use efficiency and total water use efficiency of Jatropha curcas L.seedlings for W2 increased by 15.5%, 14.9%, respectively. It is clear that W2 treatment not only increased water use efficiency, but increased regulation storage water capability, thus W2 treatment's Jatropha curcas L.seedlings improved water regulation and controlled water balance capability and resistance ability to drought-stress.