Mechanisms of drought adaptation: Photosynthesis and soil-leaf resistance to liquid water flow in four deciduous hardwood species.

摘要

Responses of photosynthesis (A) and soil-leaf resistance to liquid water flow (R) in drying soil were studied in white and post oak (Quercus alba L., Q. stellata Wangenh.), sugar maple (Acer saccharum March.), and black walnut (Juglans nigra) L. seedlings. Seedlings of Q. stellata showed the highest A and leaf conductance (g;Quantitative analysis of stomatal limitation (l) demonstrated an increase in l in water-stressed seedling of Q. stellata, but no change in l was observed in Q. alba and J. nigra during or after water stress. For A. saccharum, l was generally low and decreased from well-watered to water-stressed conditions. After 5 days of rewatering, both stomatal and mesophyll components of A in A. saccharum and J. nigra had not recovered to pre-drought levels while they had completely recovered in Q. stellata and Q. alba. Exposure of leaves to ;At high soil moisture (