Differences in Big Sagebrush (Artemisia tridentata) Plant Stature along Soil-Water Gradients: Genetic Components

Abstract

Genotypic and phenotypic variations are characteristic among big sagebrush (Artemisia tridentata) plants. One obvious expression is the variability of big sagebrush plant stature along soilwater gradients. Large phmts are usually associated with mesic habitats such as drainages or swales, while small plants occupy the xeric portions of the gradients. The purpose of this study was to investigate the genetic influence on big sagebrush plant stature along soil-water gradients. Leaf morphological, phenological, chromatographical, and cytological investigations evaluated potential genetic differences and examined possible subspecies status of the huge and small plants. The results of these studies revealed a genetic difference between the large and small plants and confirmed subspecies status. The large plants were identified as basin big sagebrush (A. tridentata spp. tridentata) while the small plants were Wyoming big sagebrush (A. tridentata spp. wyomingensis). Three additional studies examined nossible differences in arowth Genotypic and phenotypic variation is characteristic of big sagebrush (Beetle 1960, Hanks et al. 1973, McArthur et al. 1981, West et al. 1978). An obvious expression is the variability in big sagebrush plant stature along soil-water gradients (Beetle 1960, Hall and Clements 1923, Hanks et al. 1973). Large plants may reach a height of 3.5 to 5.0 m in mesic habitats such as drainages or swales, while plants less than 1 .O m tall are associated with the xeric portions of moisture gradients. Considering the differences in big sagebrush plant stature, a logical question arises: Are the differences in plant stature due to genetic or environmental influences? The research herein discusses the influence of genetics on big sagebrush plant stature. Edaphic differences associated with the large and small big sagebrush plants are reported elsewhere (Barker 198 I, Barker and McKell 1983). Study Sites potential between the subspecies.'A greenhouse and &form _ garden study compared seedling and juvenile plmt growth. Three sites were selected for study because of differences in plant Annual leader growth of mature plants was measured in native stature that were observed within relatively short distances (Barker populations. Basin big sagebrush plants outgrew Wyoming big and McKell 1983). At each site, plant height decreased with dissagebrush in the greenhouse, uniform garden, and leader growth tance along a transect at a right angle to a drainage. Plant height experiments. Difference in growth potential between the subspe-along the drainages averaged 2.5 m and decreased to less than 1.0 ties may be a consequence of ploidy diierences. m. The distance of the plant height gradient transects were 60,40, and 100 m for Sage Creek. Greasewood Wash. and Maeser. The most common, important, and widely distributed woody sagebrush (Artemisia L. subgenus tridentatae (Rydb.) E.D. McArthur) is big sagebrush (Artemisia tridentata Nutt.). Big sagebrush is common on millions of hectares throughout western North America from sout...

Big sagebrush: A sea fragmented into lakes, ponds, and puddles

“…The haploid chromosome number "n"-due to presence of two ploidy levels, "x" is the proper term-of big sagebrush has been intensively studied (Barker and McKell 1986;Kelsey and others 1975;others 1979, 1981;McArthur and Sanderson 1999;McArthur and Welch 1982;Sanderson and others 1989;Stahevitch and Wojtas 1988;Taylor and Brockman 1966;Taylor and others 1964;. The results of all these studies agree that the base number of chromosomes for big sagebrush is 9 (n = x = 9; fig.…”

“…5.2) and 2n = 4x = 36 ( fig. 5.3) (Barker and McKell 1986;Kelsey and others 1975;others 1979, 1981;McArthur and Sanderson 1999;Sanderson and others 1989;Stahevitch and Wojtas 1988;Taylor and Brockman 1966;Taylor and others 1964;). …”

“…Wyoming big sagebrush appears to be uniformly tetraploid (4x = 36), that is, all populations examined to date were tetraploids (Barker and McKell 1986;others 1979, 1981;McArthur and Sanderson 1999;Sanderson and others 1989). Basin and mountain big sagebrush are of mixed ploidy levels having both diploid and tetraploid populations (McArthur and Sanderson 1999).…”

Assessing the Influence of Different Atmospheric and Soil Mercury Concentrations on Foliar Mercury Concentrations in a Controlled Environment

“…6). A. tridentate is an evergreen desert species and the majority of growth occurs in the spring when more water is available (Barker & McKell, 1986). The fact that this species showed greater foliar accumulation and fluxes relative to J. scopulorum may be due to the maintained water content of 8-12%, which is high for A. tridentate, and allowed for optimal and sustained growth and transpiration.…”

Trade-off between plant growth and defense? A comparison of sagebrush populations

“…(Welch and Jacobsen 1988). This slow-growing subspecies is especially drought tolerant (Barker and McKell 1986;Booth et al 1990), perhaps because of its high resistance to xylem cavitation (Kolb and Sperry 1999). It is uniformly tetraploid, whereas the other two subspecies are usually diploid.…”