Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarb...

Stomata are microscopic pores formed by specialized cells in the leaf epidermis and permit gaseous exchange between the interior of the leaf and the atmosphere. Stomata in most plants are separated by at least one epidermal pavement cell and, individually, overlay a single substomatal cavity within the leaf. This spacing is thought to enhance stomatal function. Yet, there are several genera nat...

Understanding the variation in stomatal characteristics in relation to climatic gradients can reveal the adaptation strategies of plants, and help us to predict their responses to future climate changes. In this study, we investigated stomatal density (SD) and stomatal length (SL) in 150 plant species along an elevation gradient (540-2357 m) in Changbai Mountain, China, and explored the pattern...

The process of photosynthesis is facilitated in a plant by pores in its surface called stomata. When a particular stoma is open, CO2 is absorbed through its aperture, but H2O is also lost due to evaporation. Thus a plant will seek a stomatal aperture that balances its need for CO2 with its aversion to H2O loss. In order to visualize a particular leaf’s stomatal aperture distribution and how it ...

The main objectives of this study were to elucidate the roles of silicon (Si) in alleviating the effects of 2 mM zinc (high Zn) stress on photosynthesis and its related gene expression levels in leaves of rice (Oryza sativa L.) grown hydroponically with high-Zn stress. The results showed that photosynthetic parameters, including net photosynthetic rate, transpiration rate, stomatal conductance,...

12 While the significance of elevated atmospheric CO2 concentration on instantaneous leaf13 level processes such as photosynthesis and transpiration is rarely disputed, its integrated 14 effect at ecosystem level and at long-time scales remains a subject of debate. In part, the 15 uncertainty stems from the inherent leaf-to-leaf variability in gas exchange rates. By 16 combining 10 years of lea...

BACKGROUND AND AIMS Leaf hydraulic properties are strongly linked with transpiration and photosynthesis in many species. However, it is not known if gas exchange and hydraulics will have co-ordinated responses to climate change. The objective of this study was to investigate the responses of leaf hydraulic conductance (Kleaf) in Glycine max (soybean) to growth at elevated [CO2] and increased te...

nineteen bread wheat genotypes were selected to examine the effect of glycine betaine (gb, 100 mm) on various photosynthetic gas exchange parameters under drought stress and to study the relationship of these parameters with non-enzymatic antioxidants. drought stress caused a significant decline in net co2 assimilation rate (pn), stomatal conductance (gs), intercellular co2 concentration (ci) a...

a solution culture experiment was conducted to evaluate the salinity tolerance of 15 tomato genotypes in hoagland’s nutrient solution with three levels of nacl (0, 75, and 150 mm). the experiment was conducted in completely randomized design with three replicates. after 30 days of imposition of salt stress, gas exchange parameters including transpiration rate, stomatal conductance, co2 assimila...

Salicylic acid (SA) a naturally occurring plant hormone is an essential signal molecule recognized to have diverse effects on biotic and abiotic stress tolerance. The present study was planned to investigate the role of SA in salt tolerance of maize. Experiment was conducted to study the SA induce physiological and biochemical changes in two genotypes of maize viz., Sahiwal-2002 and EV-20 in th...