To evaluate the applicability of leaf and canopy photosynthesis models, we compared performance of 6 leaf models and validated 1 canopy model of photosynthesis based on field data of black locust (Robinia pseudoacacia L.) plantations on a Loess Plateau in northern China. Leaf photosynthetic light response curves and diurnal canopy photosynthetic rates were observed in the field in August 2009. ...

to study the effects of below leaves excision and nitrogen application on stomatal characteristics of wheat flag leaf, grain protein, dry matter remobilization, grain yield and yield component, leaf area of winter wheat (t. aestivum cv. ghods) was artificially reduced under filed condition. the experimental design was a factorial on a rcb with 3 replications, a combination of three levels of de...

A model to evaluate photon transport within leaves and the implications for photosynthesis are investigated. A ray tracing model, Raytran, was used to produce absorption profiles within a virtual dorsiventral plant leaf oriented in two positions (horizontal/vertical) and illuminated on one of its two faces (adaxial/abaxial). Together with chlorophyll profiles, these absorption profiles feed a s...

Active gibberellin (GA(1)) is an important mediator of thermoperiodic growth in pea. Plants grown under lower day than night temperature (negative DIF) elongate less and have reduced levels of GA(1) compared with plants grown at higher day than night temperature (positive DIF). By comparing the wild type (WT) and the elongated DELLA mutant la cry(s), this study has examined the effect of impair...

Reduction of hydraulic conductance to the canopy has been shown to result in stomatal responses to limit transpiration. To test for similar responses to perturbations of the hydraulic network in leaves, we simultaneously measured leaf gas exchange with spatially explicit chlorophyll-a fluorescence and leaf temperature to examine the effects of cutting a primary leaf vein in Helianthus annuus. W...

A quantitative analysis was applied to the stomatal and biochemical limitations to light-saturated net photosynthesis under optimal field conditions in mature trees and seedlings of the co-occurring evergreen oak, Quercus ilex L., and the deciduous oak, Q. faginea Lam. Stomatal limitation to photosynthesis, maximal Rubisco activity and electron transport rate were determined from assimilation v...

The atmospheric concentration of CO2 will probably rise to about 700 micromol mol(-1) by the end of this century. The effects of elevated growth CO2 on photosynthesis are still not fully understood. Effects of elevated growth CO2 on the capacity for photosynthesis of a single leaf and a whole plant were investigated with the radish cultivar White Cherish. The plants were grown under ambient ( a...

Rhamnus cathartica is an invasive shrub capable of high fecundity in North America. The physiology of R. cathartica has received little attention, but more is needed to understand traits that enhance its success in disturbed environments. Such data may help to predict invasiveness of closely related species such as Frangula caroliniana. We hypothesized that R. catharticawould have greater relat...

The interactions between CO(2) and H(2)O vapor exchange of the leaf and respirant organs like stems were studied in tobacco plants. The results were analyzed according to a suggested model. Good agreement between open and closed system measurements supported the validity of the model.The measured over-all resistance to CO(2) of a leaf and a stem enclosed in a measuring cuvette was the same as t...