Plant diurnal oscillation is a 24-hour period based variation. The correlation between diurnal genes and biological pathways was widely revealed by microarray analysis in different species. Rice (Oryza sativa) is the major food staple for about half of the world's population. The rice flag leaf is essential in providing photosynthates to the grain filling. However, there is still no comprehensi...

rounded leaf tip. The leaf collar marks the junction of the leaf blade and sheath and appears when the leaf is fully developed. Each leaf sheath originates at its own node on the plant stalk. The sheath surrounds and strengthens the stalk (culm). The flag leaf is the last to emerge on the plant and is considerably smaller than the other leaves. The panicle (head) emerges from the flag leaf shea...

The fortification of cereal grains with metal micronutrients is a major target to combat human malnutrition of Fe and Zn. Based on recent studies showing that N fertilization can promote Fe and Zn accumulation in cereal grains, we investigated here the influence of nitrate- or ammonium-based N fertilization on the accumulation of Fe, Zn, and Cu as well as metal chelator pools in flag leaves and...

Terminal drought stress decreases crop yields by inducing abscisic acid (ABA) and premature leaf senescence. As potassium (K) is known to interfere with ABA homeostasis we addressed the question whether there is genetic variability regarding the role of K nutrition in ABA homeostasis and drought tolerance. To compare their response to drought stress, two barley lines contrasting in drought-indu...

to study the effects of below leaves excision and nitrogen application on stomatal characteristics of wheat flag leaf, grain protein, dry matter remobilization, grain yield and yield component, leaf area of winter wheat (t. aestivum cv. ghods) was artificially reduced under filed condition. the experimental design was a factorial on a rcb with 3 replications, a combination of three levels of de...

Growth at elevated CO2 often decreases photosynthetic capacity (acclimation) and leaf N concentrations. Lower-shaded canopy leaves may undergo both CO2 and shade acclimation. The relationship of acclimatory responses of flag and lower-shaded canopy leaves of wheat (Triticum aestivum L.) to the N content, and possible factors affecting N gain and distribution within the plant were investigated i...

The transcriptomes of senescing flag leaves collected from barley field plots with standard or high nitrogen supply were compared to identify genes specifically associated with nitrogen remobilization during leaf senescence under agronomically relevant conditions. In flag leaves collected in field plots with high nitrogen supply, the decline in chlorophyll content was delayed. By comparing chan...

Ribonucleases (RNases) degrade RNA and exert a major influence on gene expression during development and in response to biotic and abiotic stresses. RNase activity typically increases in response to pathogen attack, wounding and phosphate (P(i)) deficiency. Activity also increases during senescence and other programmed cell death processes. The air pollutant ozone (O(3)) often induces injury an...

The pattern of senescence was studied by following the changes in chlorophyll and protein in the leaves and by measuring (32)P retention and export from source to sink during development of the rice plant (Oryza sativa L. cv. Jaya) subjected to different manipulative treatments. With the advance of reproductive development, the chronological sequence of leaf senescence was changed, so that the ...

The effect of water stress on glutathione reductase and catalase activities was evaluated in leaf blades of field-grown winter wheat (Triticum aestivum L.). Wheat was sown at two seeding rates under both irrigated and dryland conditions. Flag leaves from dryland plants sown at 60 kilograms/hectare showed no change in either glutathione reductase or catalase activities per unit leaf area, while ...