COMPARATIVE STUDY ON DROUGHT RESISTANCE OF IARIX OLGENSIS HENRY AND PINUS SYLVESTRIS VAR. MONGOLICA (I) -- THE INFLUENCE OF SOIL WATER CONTENT ON SEEDLINGS PLANT ING IN FLOWERPOT

摘要

Water potential (psi_w) and net photosynthelic rate (Pn) of Larix olgenxix and Pinus. xylvextrix var. mongolica decreased with the decrease of soil water content, psi_w and Pn of A. olgenxix changed hardly during the first 9 days alter stopping watering, then decreased sharply al the 10th day Pn of P. xylvustris var mongolica decreased slightly during the first 8 days, then decreased sharply at the 9th day. Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The following3 conclusions were obtained and discussed exhaustively. (1) psi_w can he used to direct watering as a sensitive index of judging whether L. olgensis and P. sylvestris var. mongolica lacking water. (2) The decrease of Pn of L. olgensis and P. xylvextris var. mongolica when drought had nolhing to do with chlorophyll. (3) P. sylvexlris var. mongolica had morphological drought resistance, while L. ol-gunxix had physiological drought resistance, and their drought resistance was discussed comparatively firsttime.