The gravitational component of water potential and frictional resistance during transpiration lead to substantial reductions in leaf water potential (Psi(l)) near the tops of tall trees, which can influence both leaf growth and physiology. We examined the relationships between morphological features and gas exchange in foliage collected near the tops of Douglas-fir (Pseudotsuga menziesii (Mirb....

The present experiment was conducted to assess the interactive effect of foliar application of nitric oxide (NO) and salinity on wheat (Triticum aestivum L.). Wheat cv. S-24 was grown under non-stressed or salt stressed conditions (0 and 150 mM NaCl). Different levels of NO (water spray, 0.05, 0.10 and 0.15 mM) were applied as a foliar spray. Salinity applied through rooting medium significantl...

At the molecular level, folivory activity on plants has mainly been related to the foliar concentrations of nitrogen (N) and/or particular metabolites. We studied the responses of different nutrients and the whole metabolome of Quercus ilex to seasonal changes and to moderate field experimental conditions of drought, and how this drought may affect folivory activity, using stoichiometric and me...

The objectives of this study were to examine the foliar sensitivity to ozone exposure of 12 tree, shrub, and herbaceous species native to southern Switzerland and determine the seasonal cumulative ozone exposures required to induce visible foliar injury. The study was conducted from the beginning of May through the end of August during 2000 and 2001 using an open-top chamber research facility l...

Plant nutritionist have traditionally considered the obvious way to feed plants is through the soil, where plant roots are meant to uptake water and nutrients, but in recent years foliar feeding has been developed to supply plants with their nutritional needs. The development of pressurised irrigation equipment such as drip irrigation has promoted the need for water-soluble fertilisers, as clea...

Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE) and 100 mg L-1 kinetin solution alone...

A series of pot experiments were conducted to: (1) evaluate the effects of different Si sources (soil- and foliar-applied) on grain yield and Si accumulation of rice supplied with varying P rates, and (2) evaluate Si absorption of rice using foliar- and soil-applied Si fertilizers. Three P rates, (0, 112, and 224 kg ha-1) combined with five Si treatments (wollastonite and slag applied at 4.5 to...

Forests of northeastern North America have been exposed to anthropogenic acidic inputs for decades, resulting in altered cation relations and disruptions to associated physiological processes in multiple tree species, including sugar maple (Acer saccharum Marsh.). In the current study, the impacts of calcium (Ca) and aluminum (Al) additions on mature sugar maple physiology were evaluated at the...

1. The concentration, stoichiometry and resorption of nitrogen (N) and phosphorus (P) in plant leaves are often used as proxies of the availability of these growth-limiting nutrients, but the responses of these metrics to changes in nutrient availability remain largely untested for tropical forest trees. 2. We evaluated changes in N and P concentrations, N/P ratios and resorption for four commo...

The aim of this paper is to review the current knowledge on the uptake of mineral nutrients from foliar fertilization. Despite many studies carried out on mineral nutrient absorption by leaf tissues, many aspects of foliar fertilization are still unknown. At present, it is believed that such fertilization of plants is a valuable complement to the application of nutrients to the soil. Foliar fer...