Leaf respiration is an important component of carbon exchange in terrestrial ecosystems, and estimates of leaf respiration directly affect the accuracy of ecosystem carbon budgets. Leaf respiration is inhibited by light; therefore, gross primary production (GPP) will be overestimated if the reduction in leaf respiration by light is ignored. However, few studies have quantified GPP overestimatio...

The effect of leaf age on photosynthetic capacity, a critical parameter in the theory of optimal leaf longevity, was studied for two tropical pioneer tree species, Cecropia longipes and Urera caracasana, in a seasonally dry forest in Panama. These species continuously produce short-lived leaves (74 and 93 d, respectively) during the rainy season (May-December) on orthotropic branches. However, ...

Grier, C.C., Elliott, K.J. and McCullough, D.G., 1992. Biomass distribution and productivity of Pinus edulis-Juniperus monosperma woodlands of north-central Arizona. For. Ecol. Manage., 50: 331350. Above-ground biomass distribution, leaf area, above-ground net primary productivity and foliage characteristics were determined for 90and 350-year-old Pinus edulis-Juniperus monosperma ecosystems on ...

WSX-1 is a component of the IL-27R. Analyses of WSX-1 knockout (WSX-1(-/-)) mice have shown that IL-27/WSX-1 signaling is essential for the proper development of T(h)1 responses and that WSX-1 can suppress cellular activation and pro-inflammatory cytokine production. We have generated transgenic mouse lines over-expressing the WSX-1 gene under the control of the T cell-specific CD2 promoter (WS...

the digestibility and fermentation parameters of the diets containing leaf, pod and seed of the subabul tree in sheep was determined by using two steps digestion and gas production (gp) methods. the experimental diets consisted of 0.0 (control), 25, 50, 75 and 100 percent of the leaf, pod and seed of the subabul tree that were replaced with alfalfa in diets of sheep. diets containing 50 percent...

Declining net primary production (NPP) with forest age is often attributed to a corresponding decline in gross primary production (GPP). We tested two hypotheses explaining the decline of GPP in ageing stands (14-115 years old) of Pinus taeda L.: (1) increasing N limitation limits photosynthetic capacity and thus decreases GPP with increasing age; and (2) hydraulic limitations increasingly indu...

Apple flea weevil, Orchestes pallicornis (Say) was a sporadic pest in the early 1900s and has reemerged as a severe pest of cultivated apple (Malus domestica Borkh.) inMichigan. Organic apple orchards inMichigan have had outbreak population levels of apple flea weevil since 2008 and damage has resulted in up to 90% losses. Apple flea weevil is a small, 2–3-mm black weevil with enlarged high leg...

Current streambank restoration efforts focus on providing bank stability, enhancing water quality, and improving woody habitat using native vegetation rather than traditional engineering techniques. However, in most cases harsh site conditions limit restoration success. A two-year field study was conducted at Twentymile Creek, in northern Mississippi, investigating edaphic factors governing the...

Litter-induced pulses of nutrient availability could play an important role in the productivity and nutrient cycling of forested ecosystems, especially tropical forests. Tropical forests experience such pulses as a result of wet-dry seasonality and during major climatic events, such as strong El Niños. We hypothesized that (1) an increase in the quantity and quality of litter inputs would stimu...

trans-acting siRNAs (ta-siRNAs) are endogenous RNAs that direct the cleavage of complementary mRNA targets . TAS gene transcripts are cleaved by miRNAs; the cleavage products are protected against degradation by SGS3, copied into dsRNA by RDR6, and diced into ta-siRNAs by DCL4 . We describe hypomorphic rdr6 and sgs3 Arabidopsis mutants, which do not exhibit the leaf developmental defects observ...