Publications

cyanide toxicosis in goats after ingestion of california holly (heteromeles arbutifolia).	cyanogenic glycosides are found in many native and naturalized plants throughout north america. the glycosides themselves are not toxic, but they yield hydrogen cyanide (hydrocyanic or prussic acid) when they are hydrolyzed by beta-glycosidases, either as a result of injury to the plant cells or by microbial action in the rumen. hydrogen cyanide is readily absorbed from the gastrointestinal tract. cyanide ion binds with iron in cytochrome oxidase, interfering with cellular respiration. the clini ...	2003	14535552
relative densities of natural enemy and pest insects within california hedgerows.	research on hedgerow design for supporting communities of natural enemies for biological control lags behind farmer innovation in california, where assemblages of perennial plant species have been used on crop field margins in the last decade. we compared natural enemy to pest ratios between fields with hedgerows and fields with weedy margins by sampling beneficial insects and key pests of vegetables on sticky cards. we used biweekly vacuum samples to measure the distribution of key insect taxa ...	2013	23905731
tissue water relations of four co-occurring chaparral shrubs.	chaparral shrubs of california have a suite of morphological and physiological adaptations to withstand the prolonged summer droughts of a mediterranean climate. not all species of chaparral have the same rooting depth and there is some evidence that those with shallow roots have tissue that is most tolerant to water stress. we tested this notion by comparing the tissue water relations of four co-occurring chaparral shrubs: quercus durata, heteromeles arbutifolia, adenostoma fasciculatum, and rh ...	1986	28311494
water use patterns of four co-occurring chaparral shrubs.	mixed stands of chaparral in california usually contain several species of shrubs growing close to each other so that aerial branches and subterranean roots overlap. there is some evidence that roots are stratified relative to depth. it may be that root stratification promotes sharing of soil moisture resources. we examined this possibility by comparing seasonal water use patterns in a mixed stand of chaparral dominated by four species of shrubs: quercus durata, heteromeles arbutifolia, adenosto ...	1986	28311654
the thermal conductivity of leaves.	thermal conductivities of fresh leaves, both unmodified and infiltrated with water, were measured. samples were placed between silver plates of known and differing temperatures, and the time required to boil off a constant volume of liquid was measured. the species used are evergreens: eucalyptus globulus labill. (sclerophyllous) with isolateral leaf symmetry; and peperomia obtusifolia a. dietr. (succulent), citrus limon burm. f. (mesophyllous), arbutus menziessii pursh. (sclerophyllous), and he ...	1975	24435441
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
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
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
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