Plants initiate leaf senescence to relocate nutrients and energy from aging leaves to developing tissues or storage organs for growth, reproduction, and defense. Leaf senescence, the final stage of leaf development, is regulated by various environmental stresses, developmental cues, and endogenous hormone signals. Jasmonate (JA), a lipid-derived phytohormone essential for plant defense and plan...

Leaf expansion in the fast-growing tree, Populus x euramericana was stimulated by elevated [CO(2)] in a closed-canopy forest plantation, exposed using a free air CO(2) enrichment technique enabling long-term experimentation in field conditions. The effects of elevated [CO(2)] over time were characterized and related to the leaf plastochron index (LPI), and showed that leaf expansion was stimula...

The aim of this study is to understand the parameters regulating calcium ion distribution in leaves. Accumulation of ions in leaf tissue is in part dependent on import from the xylem. This import via the transpiration stream is more important for ions such as calcium that are xylem but not phloem mobile and cannot therefore be retranslocated. Accumulation of calcium was measured on bulk coriand...

Although comparative studies have revealed much about the environmental correlates of leaf lifespan and its integration with other leaf traits, a comprehensive theory of leaf lifespan is still lacking. The influence of growth rate on self-shading may be a key proximate determinant of both interand intra-specific variation in leaf lifespans. If this were the case, we would expect leaf lifespans ...

Midday leaf CO2 exchange rate (CER), concentration of chlorophyll (Chl) and soluble protein and activity of the primary enzymes involved in leaf photosynthesis and sucrose metabolism were determined during leaf ontogeny for sugarcane plants grown at ambient (360 mmol mol ) and double-ambient (elevated, 720 mmol mol ) CO2. Although leaf CER of both CO2 treatments increased and was highest at 14 ...

Betel quid containing areca nut and chewing tobacco is used in many parts of India. In this study we evaluated the micronuclei (MN) in buccal mucosa of healthy individuals from southern India, who were regularly chewing a mixture of betel leaf, areca nut and tobacco. A total of 44 subjects were examined. The study population included 15 chewers, 14 chewers with smoking habit and 15 controls wit...

Centella asiatica (CeA) is a creeping herb, growing in moist places in India and other Asian Countries. Ayurvedic system of medicine, an alternate system of medicine in India, uses leaves of CeA for memory enhancement. Here, we have investigated the role of CeA fresh leaf juice treatment during growth spurt period of rats on dendritic morphology of amygdaloid neurons, one of the regions concern...

Statistical and radiative-transfer physically based studies have previously demonstrated the relationship between leaf water content and leaf-level reflectance in the near-infrared spectral region. The successful scaling up of such methods to the canopy level requires modeling the effect of canopy structure and viewing geometry on reflectance bands and optical indices used for estimation of wat...

Leaf-stem allometry is an important spectrum that linked to biomass allocation and life history strategy in plants, although the determinants and evolutionary significance of leaf-stem allometry remain poorly understood. Leaf and stem architectures - including stem area/mass, petiole area/mass, lamina area/mass, leaf number, specific leaf area (LA), and mass-based leafing intensity (LI) - were ...

Leaves experience predictable 24-h (diel) fluctuations in environmental factors such as light and temperature, as well as in energy availability. Accordingly, leaf growth is among the many processes regulated by the circadian clock. Despite the importance of leaf growth to the plant, it is relatively poorly understood, in large part due to the difficulty of tracking growth in leaves compared wi...