/pdf/north-america-floras-manuals-checklist-a-bibliography-5d763hxs6y.pdf

A Flora of New Mexico.

North America Floras, Manuals, & Checklist: A Bibliography

background

Wildland shrubs of the United States and its Territories: thamnic descriptions: volume 1.

Evolutionary ecologists have long sought to understand the conditions under which perennial (iteroparous) versus annual (semelparous) plant life histories are favored. We evaluated the idea that aridity and variation in the length of droughts should favor the evolution of an annual life history, both by decreasing adult survival and by increasing the potential for high seedling survival via reduced plant cover. We calculated phylogenetically independent contrasts of climate with respect to life history in a clade of winter-establishing evening primroses (sections Anogra and Kleinia; Oenothera; Onagraceae), which includes seven annuals, 12 perennials, and two variable taxa. Climate variables were quantified from long-term records at weather stations near collection localities. To explicitly account for phylogenetic uncertainty, contrasts were calculated on a random sample of phylogenetic trees from the posterior distribution of a Bayesian analysis of DNA sequence data. Statements of association are based on comparing the per- tree mean contrast, which has a null expectation of zero, to a set of per-tree mean contrasts calculated on the same trees, after randomizing the climate data. As predicted, increased annual aridity, increased annual potential evapo- transpiration, and decreased annual precipitation were associated with transitions to the annual habit, but these trends were not significantly different from the null pattern. Transitions to the annual habit were not significantly associated with increases in one measure of aridity in summer nor with increased summer drought, but they were associated with significantly increased maximum summer temperatures. In winter, increased aridity and decreased precipitation were significantly associated with transitions to the annual habit. Changes in life history were not significantly associated with changes in the coefficient of variation of precipitation, either on an annual or seasonal (summer vs. winter) basis. Though we cannot attribute causality on the basis of a correlational, historical study, our results are consistent with the idea that increased heat and drought at certain times of the year favor the evolution of the annual habit. Increased heat in summer may cause adult survival to decline, while increased aridity and decreased precipitation in the season of seedling recruitment (winter) may favor a drought-avoiding, short-lived annual strategy. Not all of the predicted patterns were observed: the capability for drought-induced dormancy may preclude change in habit in response to summer drought in our study group.

/pdf/climate-and-life-history-evolution-in-evening-primroses-3hc7yr481v.pdf

Climate and life-history evolution in evening primroses (Oenothera, Onagraceae) : A phylogenetic comparative analysis

ADDITIONAL INDEX WORDS. grapevines, water potential, photosynthesis, stomatal conductance, drought tolerance ABSTRACT. A comparison was made among 16 native North American Vitis species and Vitis vinifera L. ('Carignane') grown in the San Joaquin Valley of California with or without irrigation over 2 years. Predawn water potential (ΨPD), predawn leaf osmotic potential (Ψπ), midday leaf (Ψl), and stem water potential (Ψstem), stomatal conductance (gs), net CO2 assimilation rate (A), and intrinsic water use efficiency (WUE) were measured on five dates during the growing season the first year of the study and pruning weights were evaluated both years. Net gas exchange and water potential components taken on the last measurement date in 1992 and pruning weights of the nonirrigated species were less (or more negative for Ψ components) than those of the irrigated vines. The 17 Vitis species were ranked according to their relative drought tolerance based upon their performance without irrigation and when compared to their irrigated cohort. The Vitis species considered most drought tolerant were V. californica, V. champinii, V. doaniana, V. longii, V. girdiana, and V. arizonica. Those six species generally had high values of A, gs, and pruning weights and more favorable vine water status at the end of the study than the other species when grown without irrigation. The drought-induced reductions in the measured parameters also were less for those species when compared to their irrigated cohorts. The least drought tolerant species were, V. berlandieri, V. cinerea, V. lincecumii, V. riparia, and V. solonis. The drought-tolerant rankings were generally associated with the species' native habitat and probable soil water availability. sensitivity to changes in air humidity than did 'Shiraz' or 'Merlot' grapevines (Winkel and Rambal, 1990). There has been relatively little work done on the effects of soil water deficits on other Vitis species. The objective of this study was to rank the relative drought tolerance of 17 Vitis species under irrigated and nonirrigated conditions in the San Joaquin Valley of California. This was accomplished by measuring leaf water rela- tions, gas exchange and vine growth and then comparing each species within the nonirrigated portion of the vineyard with one another and with their irrigated cohort. In addition to several North American species, which are used either as commercial rootstocks or parents of other grape rootstocks, this study included several Vitis species indigenous to the arid southwestern United States. It was expected that the diverse, native habitats of the 17 species would have selected for a wide range drought tolerance characteristics that may be of use in future rootstock breeding programs.

/pdf/vine-water-relations-gas-exchange-and-vegetative-growth-of-35e1t56vkx.pdf

Vine Water Relations, Gas Exchange, and Vegetative Growth of Seventeen Vitis Species Grown under Irrigated and Nonirrigated Conditions in California

/pdf/agrostology-an-introduction-to-the-systematics-of-grasses-2k46xwuuhm.pdf

A Flora of New Mexico.

Citations

North America Floras, Manuals, & Checklist: A Bibliography

Wildland shrubs of the United States and its Territories: thamnic descriptions: volume 1.

Climate and life-history evolution in evening primroses (Oenothera, Onagraceae) : A phylogenetic comparative analysis

Vine Water Relations, Gas Exchange, and Vegetative Growth of Seventeen Vitis Species Grown under Irrigated and Nonirrigated Conditions in California

Agrostology; An Introduction to the Systematics of Grasses

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