Publications

ecology of so2 resistance: ii. photosynthetic changes of shrubs in relation to so2 absorption and stomatal behavior.	in an effort to predict so2 sensitivity of plants from their morphological and physiological features, the effects of so2 on photosynthesis were partitioned between stomatal and nonstomatal components for a drought deciduous shrub, diplacus aurantiacus, and an evergreen shrub, heteromeles arbutifolia. as predicted, the drought deciduous shrub had the higher gas conductance, and hence so2 absorptance. however, nonstomatal components also play a role in determining so2 sensitivity. apparently a pl ...	1979	28310283
ecology of so2 resistance: i. effects of fumigations on gas exchange of deciduous and evergreen shrubs.	a unique gas exchange system is described in which photosynthesis, transpiration, and stomatal conductance can be measured on leaves during so2 fumigations. so2 concentrations can be continuously monitored and manipulated between 0 and 2.0 ppm. rates of total so2 uptake and so2 absorption through stomates of a fumigated leaf can also be determined.using this system we compared the effects of so2 on the gas exchange rates of two shrub species that co-occur in the califormian chaparral. diplacus a ...	1979	28310282
environmental controls on the seasonality of a drought deciduous shrub, diplacus aurantiacus and its predator, the checkerspot butterfly, euphydryas chalcedona.	diplacus aurantiacus produces a full canopy of leaves during the rainy winter and spring. as the drought begins in summer, all but the terminal leaves are lost. the leaves present during the growth period have a comparatively low specific weight and a high content of water, protein, and non-structural carbohydrate on a weight basis. leaves of this type have a high carbon-gain per unit dry matter investment.the larvae of euphydryas chalcedona utilize diplacus as their principal food source. follo ...	1980	28309522
temporal and spatial variability in the interaction between the checkerspot butterfly, euphydryas chalcedona and its principal food source, the californian shrub, diplacus aurantiacus.	the phenology of the californian shrub, diplacus aurantiacus has been shown to be closely tied to habitat water availability, and the life cycle of the checkerspot butterfly, euphydryas chalcedona, is in turn tied to the phenological development of diplacus. here this relationship is further documented by showing how the activity patterns of both the shrub and the butterfly vary from year to year, but in synchrony, dependent on the breaking of the annual drought.the end of the feeding period for ...	1981	28311087
the effects of light and nitrogen on photosynthesis, leaf characteristics, and dry matter allocation in the chaparral shrub, diplacus aurantiacus.	plants of diplacus aurantiacus, a successional shrub common in california chaparral, were grown under controlled conditions in which either quantum flux density or nitrogen availability was varied. photosynthesis and leaf nitrogen content were determined on a leaf area and a leaf weight basis, and whole plant growth was monitored.there was a direct relationship between photosynthesis and leaf nitrogen content on both area and weight bases. reduced light intensity of the growth environment result ...	1981	28309310
coevolution of the checkerspot butterfly euphydryas chalcedona and its larval food plant diplacus aurantiacus: larval response to protein and leaf resin.	prediapause larvae of the checkerspot butterfly euphydryas chalcedona were raised from hatch until entrance into diapause on artificial diets. the proportions of protein and host plant leaf resin differed among the diets. larval size growth rates and mortality were monitored and overall rates and efficiencies of food use were computed.larval survivorship, growth rate and size of larvae at idapause were significantly enhanced by increasing dietary protein content, particularly over the range foun ...	1982	28310511
construction and maintenance costs of mediterranean-climate evergreen and deciduous leaves i. growth and co2 exchange analysis.	gas exchange and leaf growth analysis were used in conjunction to determine leaf-construction and maintenance costs in three co-occurring shrubs of the california chaparral, one evergreen, heteromeles arbutifolia, and two drougth deciduous species, lepechinia calycina, and diplacus aurantiacus. the construction costs per unit of leaf weight were similar among the three species and very close to values reported for other evergreens but considerably higher than leaf construction costs for other de ...	1982	28311111
stomatal responses to humidity of coastal and interior populations of a californian shrub.	plants of two populations of diplacus aurantiacus, a subshrub of the californian chaparral, were compared for their stomatal response to water vapor concentration gradients. plants of a coastal and an interior population were compared when grown under both low and high humidities. when grown at high humidity the coastal plants exhibited higher conductances and higher transpiration/photosynthesis ratios at all leaf-to-air water vapor concentration gradients than did the interior plants. although ...	1983	28310167
the coevolution of euphydryas chalcedona butterflies and their larval host plants : iii. oviposition behavior and host plant quality.	oviposition host preference of the checkerspot butterfly, euphydryas chalcedona, was examined in relation to the nutritional qualities of two regularly-used larval host plants. in many coastal-california colonies, e. chalcedona larvae feed primarily on a common drought-deciduous shrub, diplacus aurantiacus, but also use an herbaceous perennial, scrophularia californica. diplacus has been shown to be nutritionally inferior to scrophularia, however, diplacus may be a more persistant resource in ec ...	1983	28310213
the coevolution of euphydryas chalcedona butterflies and their larval host plants : ii. maternal and host plant effects on larval growth, development, and food-use efficiency.	the effects of foodplant species and maternal food type on larval growth, development, and digestive parameters were examined for larvae from an oligophagous colony of euphydryas chalcedona butterflies. broods of larvae from areas containing two different foodplants, diplacus aurantiacus and scrophularia californica, were divided. one group was fed their "native" host and their siblings were fed the other species. growth and digestion parameters were measured from hatching until larvae entered d ...	1983	28310212
the coevolution of euphydryas chalcedona butterflies and their larval host plants : i. larval feeding behavior and host plant chemistry.	the interactions between the checkerspot butterfly, euphydryas chalcedona, and two of its principal host plants, diplacus aurantiacus and scrophularia californica, were studied to test the hypothesis that feeding behavior in nature reflects food quality in terms of leaf nitrogen and defensive chemical contents. larvae preferentially fed on diplacus leaves containing the highest nitrogen: resin ratio in the field and laboratory. larvae did not feed selectively among scrophularia leaves, which sho ...	1983	28310211
herbivory on diplacus aurantiacus shrubs in sun and shade.	this study tested the hypothesis that carbon allocation to the production of leaf antiherbivore chemicals reflects the intensity of herbivory and interacts with resource allocation to photosynthesis. the amount of herbivory by euphydryas chalcedona butterfly larvae was measured on diplacus aurantiacus shrubs growing in different daily solar irradiance regimes. the amount of herbivory sustained by plants was directly related to the degree of solar irradiance the shrubs received and to characteris ...	1984	28312335
the seasonal dynamics of leaf resin, nitrogen, and herbivore damage in eriodictyon californicum and their parallels in diplacus aurantiacus.	the chaparral shrub eriodictyon californicum produces a flavonoid leaf resin with a chemically similar composition to that previously reported for the sympatric shrub diplacus aurantiacus. we determined the phenology, resin content, and nitrogen content of eriodictyon leaves and the leaf area lost to herbivores. nitrogen content and resin content were both negatively correlated with leaf age at each sampling date, but nitrogen decreased during the growing season while resin increased. the fracti ...	1984	28311070
interspecific variation in so(2) flux : leaf surface versus internal flux, and components of leaf conductance.	the objective of this study was to clarify the relationships among stomatal, residual, and epidermal conductances in determining the flux of so(2) air pollution to leaves. variations in leaf so(2) and h(2)o vapor fluxes were determined using four plant species: pisum sativum l. (garden pea), lycopersicon esculentum mill. flacca (mutant of tomato), geranium carolinianum l. (wild geranium), and diplacus aurantiacus (curtis) jeps. (a native california shrub). fluxes were measured using the mass-bal ...	1985	16664551
host-plant protein and phenolic resin effects on larval growth and survival of a butterfly.	euphydryas chalcedona prediapause larvae were reared on fertilized and control shrubs of the host plant,diplacus aurantiacus. larval growth was enhanced by high leaf nitrogen content and inhibited by high leaf phenolic resin content. larvae fed less on leaves near the branch tip which contained a higher leaf resin content. the results agree with prior laboratory investigation that the dietary content of nitrogen andd. aurantiacus leaf resin are major determinants ofe. chalcedona larval growth an ...	1985	24311239
the carbon balance of flowers of diplacus aurantiacus (scrophulariaceae).	measurements and modeling of photosynthesis, respiration and growth in flowers of diplacus aurantiacus, a semidrought-deciduous shrub, indicate that they can provide 18%-25% of their total carbon requirements through photosynthesis of flower parts. daily photosynthetic carbon fixation exceeds daily respiratory co2 loss during most non-fruiting stages of development. however, this carbon gain fails to meet the requirements for new biomass construction during bud growth and corolla expansion. duri ...	1985	28310794
allocation to reproduction in the chaparral shrub, diplacus aurantiacus.	the semi-drought-deciduous shrub, diplacus aurantiacus, allocates a large, relatively constant proportion of carbon and nitrogen to sexual reproduction. experimental manipulation at a site in the chaparral of coastal central california showed that both reproduction and vegetative growth were strongly limited by water and little affected by shade or by addition of nutrients unless accompanied by water. potential competition for carbon between growth and reproduction is reduced by photosynthesis w ...	1985	28310855
gas exchange and so2 fumigation studies with irrigated and unirrigated field grown diplacus aurantiacus and heteromeles arbutifolia.	experiments were performed on an evergreen (heteromeles arbutifolia) and a drought deciduous shrub (diplacus aurantiacus) to determine, 1) whether approaches for evaluating so2 absorption by leaves in laboratory studies could be extended to field studies, 2) the effects of irrigation on metabolism and so2 responses of the study species during a season when water was limiting, 3) to interpret so2 responses on the basis of so2 flux rates. laboratory-developed approaches for evaluating so2 absorpti ...	1988	28312686
interactions of so2 with other environmental stresses in influencing leaf gas exchange.	leaves of two field growing co-occuring perennial shrubs (drought-deciduous diplacus aurantiacus and the evergreen heteromeles arbutifolia) from the californian chaparral were exposed to small doses of so2. during this exposure the leaf environment was manipulated to determine how the presence of so2 alters the response of gas exchange to other environmental stresses. the data show that no direct changes in stomatal conductance (g) or net assimilation rate (a) could be attributed to short-term ( ...	1990	28312966