Increasing the nitrate (N) concentration in the rooting substrate above deficiency decreased stomatal conductance and leaf growth rate compared with sufficient N in maize seedlings (Zea mays L.) growing in drying substrate. Novel effects were detected when N in the non-deficient range was supplied directly to the xylem of detached shoots: concentrations above 2.0 mol m-3 KNO3 reduced transpirat...

Salinity tolerance of four grape genotypes [GharaUzum, Hosseini, AghUzum and Keshmeshi] was studied under various salinity levels (25, 50 and 100 mM NaCl). As a result, growth indices were significantly (P<0.05) reduced by salinity, whereas Cl- and Na+ contents in the plant parts were increased. Cl- accumulation exceeded than that of Na+ in all treatments. Among the genotypes studied, GharaUzum...

A small proportion of water molecules contain the heavier isotopes of hydrogen and oxygen. There is a tendency for these heavier molecules of water to accumulate in leaves during transpiration. This has several interesting repercussions, including effects on the isotopic composition of organic matter, and of atmospheric water vapor, carbon dioxide, and oxygen. In turn, these effects aid tempora...

The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO(2) access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 acce...

Under certain environmental conditions, nocturnal transpiration can be relatively high in temperate and tropical woody species. We have previously shown that nocturnal sap flow accounts for up to 28% of total daily transpiration in woody species growing in a nutrient-poor Brazilian Cerrado ecosystem. In the present study, we assessed the effect of increased nutrient supply on nocturnal transpir...

We observed diurnal and seasonal patterns of leaf-scale gas exchange within the crown of a Dipterocarpus sublamellatus Foxw. tree growing in a lowland dipterocarp forest at Pasoh, Peninsular Malaysia. Observations were carried out nine times over 6 years, from September 2002 to December 2007. Observation periods included both wet and mild-dry periods, and natural and saturated photosynthetic ph...

Scarcity of water for irrigation is an alarming issue limiting crop production worldwide and is becoming increasingly severe with the passage of time in Pakistan. Rice production in Pakistan is thus, being adversely hampered by the shortage of water. The study was therefore, contemplated to determine the effect of drought stress on some physiological and agronomic parameters of three rice culti...

In general, stomatal density (SD) decreases when plants are grown at high CO2 concentrations. Recent studies suggest that signals produced from mature leaves regulate the SD of expanding leaves. To determine the underlying driver of these signals in poplar (Populus trichocarpaxP. deltoides) saplings, a cuvette system was used whereby the environment around mature (lower) leaves could be control...