The effect of cadmium (Cd) on growth, photosynthesis, biochemical attributes and antioxidant enzymes activities in tomato (Solanum lycopersicum L.) seedlings was studied and the role of kinetin (KN) to ameliorate Cd toxicity was examined. Tomato seedlings were subjected to two doses of Cd viz. 3 and 9 mg Cd kgP P sand. Cadmium at both the doses significantly declined the growth and photosynthes...

change system to measure the net exchange of CO2 at the surfaces of three shady feather moss and three exposed sphagnum moss sites in a black spruce forest during 35 days at the end of the 1995 growing season. Midday gross photosynthesis was 0.5 to 1.0 μmol m s by feather moss and 0.5 to 2.5 μmol m s by sphagnum moss. Photosynthesis by sphagnum moss was reduced by approximately 70% at 0 °C, and...

Mechanical stimulation of trigger hairs on the adaxial surface of the trap of Dionaea muscipula leads to the generation of action potentials and to rapid leaf movement. After rapid closure secures the prey, the struggle against the trigger hairs results in generation of further action potentials which inhibit photosynthesis. A detailed analysis of chlorophyll a fluorescence kinetics and gas exc...

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...

Stressful episodic weather is likely to affect the C balance of trees as the climate changes, potentially altering survival. However, the role of elevated CO2 concentration ([CO2]) in tolerating off-season episodic extremes is not clear. We tested for interactive effects of elevated CO2 and springtime heat stress on photosynthesis for seven genotypes of Eucalyptus camaldulensis Dehnh. var. cama...

Jojoba (Simmondsia chinensis [Link] Schneider) is an important crop in desert climates. A relatively high frequency of periods of chilling and high photon flux density (PFD) in this environment makes photoinhibition likely, resulting in a reduction of assimilation capacity in overwintering leaves. This could explain the low net photosynthesis found in shoots from the field (4-6 micromoles per s...

Soft corals of the family Xeniidae exhibit a unique, rhythmic pulsation of their tentacles (Movie S1), first noted by Lamarck nearly 200 y ago. However, the adaptive benefit of this perpetual, energetically costly motion is poorly understood. Using in situ underwater particle image velocimetry, we found that the pulsation motions thrust water upward and enhance mixing across the coral-water bou...

The action spectrum of apparent photosynthesis for attached radish (Raphanus sativus L. var. Early Scarlet Globe) and corn (Zea mays L. var. Pride V.) leaves was measured at 300 mul/l CO(2) and both 21% and 2% O(2). The spectra were measured at light intensities where apparent photosynthesis was proportional to intensity. For radish, a high compensation point plant, oxygen had an inhibiting eff...

it is suggested that cultivars of wheat (triticum aestivum l.) with regulated growth and development would be able to produce higher yields under water-limited conditions, which is crucial in future food production. water use efficiency (wue) is worthy of exploration in this regard. in this study, the effects of nitrogen fertilizer levels (0, 40 and 80 kg nha-1) and a plant growth retardant (ch...