Gas Exchange Rates of Texas Persimmon (Diospyros texana) in Central Texas Woodlands  

作　　者：Matthew B. Grunstra Oscar W. Van Auken Matthew B. Grunstra;Oscar W. Van Auken(Department of Integrative Biology, University of Texas at San Antonio, San Antonio, TX, USA)

机构地区：[1]Department of Integrative Biology, University of Texas at San Antonio, San Antonio, TX, USA

出　　处：《American Journal of Plant Sciences》2024年第5期329-348,共20页美国植物学期刊（英文）

摘　　要：Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO₂ and temperature were measured for D. texana. The A_net (photosynthetic rate) increased significantly as both light level and CO₂ levels increased but not temperature. The A_max (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO₂ was increased for all treatments. Stomatal conductance increased with levels of CO₂ but only if the interaction was removed from the model. Intercellular levels of CO₂ increased with both temperature and CO₂ treatments as did water use efficiency (WUE). Furthermore, light saturation (L_sat) increased with CO₂ treatments and light compensation (L_cp) increased with temperature. The dark respiration (R_d) increased with both temperature and CO₂ treatments. Markov population models suggested D. texana populations would remain ecologically similar in the future. However, sub-canopy light levels and herbivory should be considered when examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles which would allow them to reach the canopy without need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus woodlands will change in the future to woodlands with D. texana a more common species.Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO₂ and temperature were measured for D. texana. The A_net (photosynthetic rate) increased significantly as both light level and CO₂ levels increased but not temperature. The A_max (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO₂ was increased for all treatments. Stomatal conductance increased with levels of CO₂ but only if the interaction was removed from the model. Intercellular levels of CO₂ increased with both temperature and CO₂ treatments as did water use efficiency (WUE). Furthermore, light saturation (L_sat) increased with CO₂ treatments and light compensation (L_cp) increased with temperature. The dark respiration (R_d) increased with both temperature and CO₂ treatments. Markov population models suggested D. texana populations would remain ecologically similar in the future. However, sub-canopy light levels and herbivory should be considered when examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles which would allow them to reach the canopy without need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus woodlands will change in the future to woodlands with D. texana a more common species.

关 键 词：Replacement Dynamics Ecological Succession CO₂ Concentrations Temperature Levels Photosynthetic Rates Drought Tolerance HERBIVORY Species Replacement ENCROACHMENT Juniper 

分 类 号：S66[农业科学—果树学]