When measured under midday fi eld conditions, modern varieties of maize (Zea mays L.) often have substomatal carbon dioxide concentration (Ci) values in excess of those required to saturate the photosynthetic carbon dioxide assimilation rate (A). This results in lower leaf transpiration effi ciency (TE), the ratio of photosynthesis to transpiration, than potentially achievable for a given rate ...

light as an important environmental factor, influences many aspects of plant growth and development. leaves are different in some characters including stomatal behavior under shade or light conditions. in this study, the effects of different levels of light intensity on stomatal behavior of two rose cultivars, ‘gulmira’ and ‘red one’, were evaluated under controlled conditions. to obtain differ...

Salinity and water stress reduces the ability of plant to take up water and decrease growth rate, photosynthesis rate (An) and stomatal conductance (gs) of plants. In this study, effects of deficit irrigation with different salinity levels and planting method (in-furrow and on-ridge) as strategies for coping with water and salinity stress on physiologic properties of rapeseed was investigat...

to evaluate the effect of different levels of drought stress on some physiological parameters in strawberry, potted experiment involing strawberry cultivars  ‘marak٫ , ‘camarosa٫ and ‘gaviota٫ was conducted during summer 2009. the experiment consisted of three drought stress levels in three replications. the experimental arrangement was a factorial one, based upon a randomized complete block de...

Our goal was to describe stomatal conductance (gs) and the site-scale environmental parameters that best predict gs in Kruger National Park (KNP), South Africa. Dominant grass and woody species were measured over two growing seasons in each of four study sites that represented the natural factorial combination of mean annual precipitation [wet (750 mm) or dry (450 mm)] and soil type (clay or sa...

Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (Ψ(lPD)), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthe...

Water stress causes defoliation, which can reduce yield and root quality of sugar beets (Beta vulgaris L.) through altered gas exchange characteristics of the leaves. In a two-year experiment, three sugar beet cultivars (Europa, Rival and Corsica) were subjected to three defoliation levels (control-C, moderate-MD, severe-SD) and re-watering after their exposition to drought for a month. Leaf ph...

Attempts to understand mechanisms underlying plant mortality during drought have led to the emergence of a hydraulic framework describing distinct hydraulic strategies among coexisting species. This framework distinguishes species that rapidly decrease stomatal conductance (gs), thereby maintaining high water potential (Px; isohydric), from those species that maintain relatively high gs at low ...

Light quality and, in particular, its content of blue light is involved in plant functioning and morphogenesis. Blue light variation frequently occurs within a stand as shaded zones are characterized by a simultaneous decrease of PAR and blue light levels which both affect plant functioning, for example, gas exchange. However, little is known about the effects of low blue light itself on gas ex...

Adequate leaf hydraulic conductance (Kleaf) is critical for preventing transpiration-induced desiccation and subsequent stomatal closure that would restrict carbon gain. A few studies have reported midday depression of Kleaf (or petiole conductivity) and its subsequent recovery in situ, but the extent to which this phenomenon is universal is not known. The objectives of this study were to measu...