Role of Temperature and Moisture in the Survival and Seedling Physiology of a Great Basin Perennial

摘要

Munro's globemallow (Sphaeralcea munroana) is an important constituent of Great Basin communities and is commonly used in restoration; however, little is known about the influence of environmental conditions on early plant establishment. The objective of this study was to evaluate the response of Munro's globemallow to a suite of temperature and moisture conditions directly following germination. In addition, this work provides a rare insight into the physiology and development of this arid land species following germination. Our results indicate that temperature influences plant growth immediately after germination more than available moisture. In a growth chamber study, germinants subject to colder temperatures (17/3°C) had 53% fewer leaves, 78% lower leaf area, and less aboveground and belowground biomass (71 and 72 %, respectively) than their cohorts grown at 23/9°C. Decreasing irrigation frequency favored biomass allocation to the roots and a subsequent increase in root-to-shoot ratios. Neither temperature nor moisture had an influence on gas exchange. This evidence suggests that although this perennial forb shows considerable potential for restoration on arid sites, it may not be the best candidate for early competition with cool season grasses during its establishment phase. Because growth is hindered by cool temperatures, a later sowing date may improve establishment in nurseries, seed production areas, and restoration sites.