Skip to main content
Advanced Search

Filters: Tags: Water Stress (X) > Extensions: Citation (X)

6 results (9ms)   

View Results as: JSON ATOM CSV
Phosphorus and nitrogen uptake capacities were assessed during 36–58 d drying cycles to determine whether the ability of sagebrush (Artemisia tridentata Nutt.) to absorb these nutrients changed as the roots were subjected to increasing levels of water stress. Water was withheld from mature plants in large (6 I) containers and the uptake capacity of excised roots in solution was determined as soil water potentials decreased from −0.03 MPa to −5.0 MPa. Phosphorus uptake rates of excised roots at given substrate concentrations increased as preharvest soil water potentials decreased to −5.0 MPa. Vmax and Km also increased as soil water potentials declined. Declining soil water potentials depressed nitrogen uptake...
Growth of vegetative and reproductive structures in Artemisia tridentata is temporally separated during the growing season; vegetative growth occurs during spring and early summer when soil moisture is most abundant, while reproductive growth occur during summer and fall when soil moisture may be limiting. Vegetative and reproductive structures may therefore exhibit contrasting efficiencies of resource acquisition and investment resulting from temporal differences in resource availability during their development. We examined the effect of water stress on growth, photosynthesis, and resource investment for vegetative and reproductive modules of Artemisia tridentata by applying supplemental water. No differences...
“The loss of foundational but fire-intolerant perennials such as sagebrush due to increases in fire size and frequency in semi-arid regions has motivated efforts to restore them, often with mixed or even no success. Seeds of sagebrush Artemisia tridentata and related species must be moved considerable distances from seed source to planting sites, but such transfers have not been guided by an understanding of local climate adaptation. Initial seedling establishment and its response to weather are a key demographic bottleneck that likely varies among subspecies and populations of sagebrush.We assessed differences in survival, growth and physiological responses of sagebrush seedlings to weather among eleven seed sources...
Uptake and release of carbon in grassland ecosystems is very critical to the global carbon balance and carbon storage. In this study, the dynamics of net ecosystem CO2 exchange (FNEE) of two grassland ecosystems were observed continuously using the eddy covariance technique during the growing season of 2003. One is the alpine shrub on the Tibet Plateau, and the other is the semi-arid Leymus chinensis steppe in Inner Mongolia of China. It was found that the FNEE of both ecosystems was significantly depressed under high solar radiation. Comprehensive analysis indicates that the depression of FNEE in the L. chinensis steppe was the results of decreased plant photosynthesis and increased ecosystem respiration (Reco)...
There is a long-standing controversy as to whether drought limits photosynthetic CO2 assimilation through stomatal closure or by metabolic impairment in C3 plants. Comparing results from different studies is difficult due to interspecific differences in the response of photosynthesis to leaf water potential and/or relative water content (RWC), the most commonly used parameters to assess the severity of drought. Therefore, we have used stomatal conductance (g) as a basis for comparison of metabolic processes in different studies. The logic is that, as there is a strong link between g and photosynthesis (perhaps co-regulation between them), so different relationships between RWC or water potential and photosynthetic...
Eight perennial C-4 grasses from the Jornada del Muerto Basin in southern New Mexico show five-fold differences in relative growth rates under well- watered conditions (RGRmax). In a controlled environment, we tested the hypothesis that there is an inverse relationship (trade-off) between RGRmax and the capacity of these species to tolerate drought. We examined both physiological (gas exchange) and morphological (biomass allocation, leaf properties) determinants of growth for these eight species under three steady-state drought treatments (none=control, moderate, and severe). When well watered, the grasses exhibited a large interspecific variation in growth, which was reflected in order-of-magnitude biomass differences...