BACKGROUND AND AIMS Grapevines growing in Australia are often exposed to very high temperatures and the question of how the gas exchange processes adjust to these conditions is not well understood. The aim was to develop a model of photosynthesis and transpiration in relation to temperature to quantify the impact of the growing conditions on vine performance. METHODOLOGY Leaf gas exchange was...

Wheat irrigated with nutrient solutions containing 0, 0.2, 0.5, 1, 2, or 6 millimolar K(+) had maximum photosynthetic rates at 1 to 2 millimolar K(+) concentrations. Rates in the 6 millimolar K(+)-grown plants were not higher than the 2 millimolar K(+)-grown wheat, and rates were inhibited below 0.5 millimolar K(+). Photosynthesis was measured by both attached whole leaf CO(2) uptake and by (14...

There is a trade-off between nitrogen (N) allocation to photosynthesis and to defence. Invasive species may reduce N allocation to defence because of the absence of natural enemies. Thus, I hypothesised that invasive species may allocate a higher fraction of total leaf N to photosynthesis and have higher light-saturated photosynthetic rate (P(max)) and photosynthetic N-use efficiency (PNUE) tha...

Mungbean (Vigna radiata (L.) Wilczek) or green gram as a dryland grain legume is exposed to varied timings and severity of drought stress, resulting in variability in photoassimilate production. In order to evaluate some physiological responses in one mungbean cultivar to timing and severity of drought stress, a 3-replicate RCBD (randomized complete block design) field experiment was carried ou...

The literature and our present examinations indicate that the intra-leaf light absorption profile is in most cases steeper than the photosynthetic capacity profile. In strong white light, therefore, the quantum yield of photosynthesis would be lower in the upper chloroplasts, located near the illuminated surface, than that in the lower chloroplasts. Because green light can penetrate further int...

To meet the growing demand for food, substantial improvements in yields are needed. This is particularly the case for wheat, where global yield has stagnated in recent years. Increasing photosynthesis has been identified as a primary target to achieve yield improvements. To increase leaf photosynthesis in wheat, the level of the Calvin-Benson cycle enzyme sedoheptulose-1,7-biphosphatase (SBPase...

Biochemical leaf photosynthesis models are evaluated by laboratory results andhave been widely used at field scale for quantification of plant production,biochemical cycles and land surface processes. It is a key issue to search forappropriate model structure and parameterization, which determine modeluncertainty. A leaf photosynthesis model that couples the Farquhar-vonCaemmerer-Berry (FvCB) f...

BACKGROUND AND AIMS Monsi and Saeki (1953) published the first mathematical model of canopy photosynthesis that was based on the light attenuation within a canopy and a light response of leaf photosynthesis. This paper reviews the evolution and development of their theory. SCOPE Monsi and Saeki showed that under full light conditions, canopy photosynthesis is maximized at a high leaf area ind...