The mechanism regulating the pattern of leaf initiation was analyzed by using shoot organization (sho) mutants derived from three loci (SHO1, SHO2, and SHO3). In the early vegetative phase, sho mutants show an increased rate of leaf production with random phyllotaxy. The resulting leaves are malformed, threadlike, or short and narrow. Their shoot apical meristems are relatively low and wide, th...

Ribulose-1,5-bisphosphate carboxylase (Rubisco) efficiency for CO2-saturated photosynthesis was examined in leaves of rice (Oryza sativa L.). The amount of Rubisco in a leaf was calculated to be 30-55% in excess for the light-saturated rate of photosynthesis at 100 Pa CO2. Long-term exposure to CO2 enrichment decreased the amount of Rubisco protein. However, N was not reallocated from decreased...

Leaf senescence is a complicated developmental process that involves degenerative changes and nutrient recycling. The progress of leaf senescence is controlled by various environmental cues and plant hormones, including ethylene, jasmonic acid, salicylic acid, abscisic acid, cytokinins, and strigolactones. The production of strigolactones is induced in response to nitrogen and phosphorous defic...

Tu-chung (Eucommia ulmoides, Oliver) is a Chinese medical herb which has been used for the sake of health for a few thousand years. In animal experiments, it was reported that Tu-chung leaf extract increased relative weight of both liver and small intestine in the rat (MA et al., 1987), and body weight of mice (YoxoGosHi et al., 1991). In laying hens, SHIOYA et al., (1990) reported that adminis...

background the production of nanoparticles using a biosystem is considered green chemistry. application of plant extracts as a biological process has been proven to be suitable for synthesis of nanoparticles. objectives this study designed in order to evaluate the production of silver nanoparticles using juglans regia leaf extract and to compare the outcome of different preparation methods of p...

Seagrass beds provide much of the primary production in estuaries; host many fishes and fish larvae, and abate erosion. The present study presents original analytical methods for estimating mean leaf-growth rates of eelgrass (Zostera marina). The method was calibrated by using data collected in a Z. marina meadow at Punta Banda estuary in Baja California, Mexico. The analytical assessments were...

Aboveand below-ground growth, biomass, phenology and reproductive effort in the seagrass Thalassia testudinum were monitored monthly for 2 yr in the Lower Laguna Madre, Texas. Annual whole plant production (953 i 136 g DW (dry weight) m-2 yr-l) was calculated from monthly measurements of leaf and rhizome production made using marking techniques. Leaf growth exhblted a seasonal pattern; monthly ...

The mechanistic understanding of isotope fractionation processes is increasing but we still lack detailed knowledge of the processes that determine the isotopic composition of the tree-ring archive over the long term. Especially with regard to the path from leaf photosynthate production to wood formation, post-assimilation fractionations/processes might cause at least a partial decoupling betwe...

Leaf elongation rate (LER) is an important factor controlling plant growth and productivity. The objective of this study was to determine whether genetic variation in LER for a fast-growing ('K-31'), and a dwarf cultivar ('Bonsai') of tall fescue (Festuca arundinacea) and gibberellic acid (GA) regulation of LER were associated with differential expression of cell-expansion genes. Plants were tr...

Southern pines vary in their response to the loss of leaf area by crown scorch. We hypothesize that they tolerate crown scorch by at least three recovery mechanisms, but the function of these mechanisms is season-dependent. Using sapling longleaf pine as a model and experimental results from central Louisiana, U.S.A., our objective is to present examples recovery from scorch, and discuss how th...