Several pest insects of human and livestock habitations are known as vectors of Salmonella enterica; however, the role of plant-feeding insects as vectors of S. enterica to agricultural crops remains unexamined. Using a hemipteran insect pest-lettuce system, we investigated the potential for transmission and retention of S. enterica. Specifically, Macrosteles quadrilineatus and Myzus persicae i...

Leaf dark respiration (R) is an important component of plant carbon balance, but the effects of rising atmospheric CO(2) on leaf R during illumination are largely unknown. We studied the effects of elevated CO(2) on leaf R in light (R(L)) and in darkness (R(D)) in Xanthium strumarium at different developmental stages. Leaf R(L) was estimated by using the Kok method, whereas leaf R(D) was measur...

The physiological mechanisms responsible for reduced extension growth as trees increase in height remain elusive. We evaluated biophysical constraints on leaf expansion in old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Needle elongation rates, plastic and elastic extensibility, bulk leaf water (Psi(L)) and osmotic (Psi(pi)) potential, bulk tissue yield threshold and final ...

Leaf-level morphological and physiological responses of mature, winter-deciduous, shade-tolerant Acer saccharum Marsh. trees to gap formation caused by selection harvest were studied experimentally over a 2-year period. We found no evidence for either physiological stress or positive acclimation following gap creation during the 1-2-week post-harvest period. Rather, lower-canopy leaves showed g...

the effect of feeding silage of leaf and stem of banana tree with waste date palm on feed intake, microbial protein synthesis and blood parameters using four adult rams in a change- over design with four 21-days period were examined. eighty five kg leaf and stem of banana tree with 15 kg of waste date palm were mixed together and ensiled for 45 days. chemical composition and sensory evaluation ...

The influence of light, gibberellic acid, and abscisic acid on unrolling of etiolated barley leaf segments was investigated. Gibberellic acid stimulated unrolling of both illuminated and nonilluminated leaf segments. In contrast, abscisic acid prevented light-stimulated unrolling and abolished the slight unrolling of segments maintained in the dark.Analysis of the time course of photoinduced un...

For organisms with complex life histories, carry-over effects (COEs) can manifest between life stages, when conditions experienced by one stage influence the next, as well as trans-generationally, when the parental environment affects offspring. Here we used multiple global change-associated stressors to examine both forms of COE simultaneously in an intertidal limpet with mixed development (i....

in order to determine radiation use efficiency and phenological and physiological characteristics of three maize hybrids on seven plant densities, an experiment was conducted during 2006 growing season in mashhad, iran. three maize hybrids including late-rippening maize (704), medium-rippening (504) and early-rippening maize (260) and seven plant densities including d1=3, d2=5, d3=7, d4=9, d5=1...

Since leaves are essentially energy-gaining organs, the arrangement of leaves in time (leaf phenology) and in space (canopy architecture) in both seasonal and nonseasonal environments can be viewed as a central element in plant strategies for carbon gain. Interrelationships among leaf longevity, leaf habit, and leaf-emergence pattern together with shoot architecture affect plant productivity. L...