Diurnal and Seasonal Water Relations of the Desert Phreatophyte Prosopis Glandulosa (Honey Mesquite) in the Sonoran Desert of California

Abstract

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Comparative Water Relations of Phreatophytes in the Sonoran Desert of California

“…8), and both had midday stomatal closure in May but not in August, as did E. farinosa and to some degree 0. tesota. Similar results were found for P. glandulosa at another wash community (Nilsen et al 1983). Even though t4 values were considerably lower in August than in May for P. glandulosa, A. greggii, and 0. tesota (Fig.…”

“…However, the data collected in this study indicate that the phreatophytes are a diverse group which exhibit several mechanisms of avoiding and tolerating water stress, as previously suggested for P. juliflora and P. glandulosa (Mooney et al 1977, Nilsen et al 1983). The phreatophytes studied in this investigation can be placed in three categories based on their phenology and water The magnitude of stomatal conductance can also be viewed as a mechanism of drought avoidance.…”

Seasonal patterns of tissue water relations in three Mediterranean shrubs co‐occurring at a natural CO2 spring

“…The osmotically active solutes were generally higher during the winter months and low at the end of the spring, but did not increase much as drought developed. Other studies on shrub species have shown the symplastic water volume fraction to remain constant with increasing leaf age and drought (Nilsen et al 1983;Davis & Mooney 1986). The symplastic water volume fraction and the symplast volume in J. communis followed a different pattern, being lowest in mid-winter, which could be beneficial at low temperatures (Gross & Koch 1991), and highest in late summer.…”

Plant water relations at elevated CO2– implications for water‐limited environments

“…Leaf π o and osmotic adjustment were not affected by elevated [CO 2 ] in sugar maple (Acer saccharum L.), American sycamore (Platanus occidentalis L.) and sweetgum, where, despite an approximate 50% increase in net carbon assimilation rate (Tschaplinski et al 1995b), there was no evidence of higher soluble carbohydrate concentrations in leaves or roots (Tschaplinski, Stewart & Norby 1995a (Polley et al 1996(Polley et al , 1999, a species that is known to osmotically adjust both diurnally and seasonally (Nilsen et al 1983). Similarly, Picon-Cochard & Guehl (1999) reported that although elevated [CO 2 ] increased sucrose concentration by 20% in Pinus pinaster Ait., there was no effect of CO 2 treatment on soluble carbohydrate concentrations during a drying cycle, leading these authors to conclude that osmotic adjustment was not enhanced under elevated [CO 2 ].…”