The effects of exogenously supplied isoprene on chlorophyll fluorescence characteristics were examined in leaf discs of four isoprene-emitting plant species, kudzu (Pueraria lobata [Willd.] Ohwi.), velvet bean (Mucuna sp.), quaking aspen (Populus tremuloides Michx.), and pussy willow (Salix discolor Muhl). Isoprene, supplied to the leaves at either 18 &mgr;L L-1 in compressed air or 21 &mgr;L L...

Leaf out time is a widely used indicator of climate change and represents a critical transition point of annual seasonality in most temperate ecosystems. We compared three sources of data to determine the effect of spring temperature on tree leaf out: field observations, remotely sensed satellite data, and experimental warming. All three methods recorded earlier leaf out with warmer spring temp...

BACKGROUND AND AIMS In species with specialized pollination, floral traits are expected to be relatively invariant and decoupled from the phenotypic variation affecting vegetative traits. However, inferring the degree of decoupling between morphological characters from patterns of phenotypic correlations is difficult because phenotypic correlations result from the superimposition of several sou...

Cold hardiness of leaf blades, leaf sheaths, culms, rhizomes, and leaf buds in wintering Sasa senanensis (Fr. et Sav.) Rehder, a dwarf bamboo, was studied paying special attention to the types of resistance mechanisms which were determined with differential thermal analysis. Coincidence of LT(25) (lethal temperature at which 25% of the tissues are injured) with the initiation temperature of LTE...

Leaf gas exchange and temperature response were measured to assess temperature acclimation within a tree canopy in climatically contrasting genotypes of Acer rubrum L. Over the course of two 50 d continuous periods, growth temperature was controlled within tree crowns and the steady-state rate of leaf gas exchange was measured. Data were then modelled to calculate the influence of genotype vari...

Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmenta...

in order to evaluate the effect of terminal water deficit stress on leaf traits and their relations to grain yield in different barley genotypes (‘yousof’, ‘fajr30’, ‘nosrat’, ‘pbyt-46’, ‘pbyt-97’ and ‘morocco’), two separated experiments were conducted in stress (water withholding from anthesis towards the end of growing season), and non stress (normal irrigation) conditions based on rcbd with...

conductance to heat transfer (gbH) and water vapor transfer (gbV) in foliated branches of Abies amabilis Dougl. ex J. Forbes, a subalpine forest tree that produces clumped shoot morphology on sun-formed branches. Boundary layer conductances estimated in the field from energy balance measurements increased linearly from approximately 10 mm s−1 at low wind speeds (< 0.1 m s−1) to over 150 mm s−1 ...

Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. I...