A single germinated rice (Oryza sativa L) seed can produce 350 grains with the sequential development of 15 leaves on the main stem and 7-10 leaves on four productive tillers (forming five panicles in total), using nitrogen (N) taken up from the environment over a 150-day growing season. Nitrogen travels from uptake sites to the grain through growing organ-directed cycling among sequentially de...

Although the nitrogen nutrition index (NNI) is a widely used indicator of plant nitrogenstatus, no model of NNI calculation for spring barley (Hordeum vulgare) reflecting also specificmalting requirements on grain has been published. The aim of this study was to determinean optimal range of the nitrogen nutrition index (ratio of nitrogen concentration in shootbiomass to critical nitrogen concen...

Despite its worldwide economic importance for food (oil, meal) and non-food (green energy and chemistry) uses, oilseed rape has a low nitrogen (N) use efficiency (NUE), mainly due to the low N remobilization efficiency (NRE) observed during the vegetative phase when sequential leaf senescence occurs. Assuming that improvement of NRE is the main lever for NUE optimization, unravelling the cellul...

Remobilization of mineral nutrients from leaves to reproductive structures is a possible regulatory factor in leaf senescence. The relationship between P remobilization from leaves of soybean (Glycine max [L.] Merr. cv McCall) during reproductive development and leaf senescence was determined by utilizing soil P treatments that supplied deficient, optimum, and supraoptimum soil P levels. The so...

field experiments were conducted at the rice research institute (mazandaran province) using randomized complete block designs in two fields of different levels of organic carbon (low and medium) during two cropping years. the treatments were repeated in three replicates and while seven nitrogen levels (urea-n input) 0, 23, 46, 69, 92, 115 and 138 kg n per ha employed. results indicated that opt...

Stay-green (SG) is a term used to describe genotypes that have delayed leaf senescence as compared reference genotypes. SG could be favorable for grain yield, silage yield and quality, double exploitation (grain feed stover bioenergy), stress resistance, etc. However, some studies show contradictory results regarding the influence of or in uptake remobilization nutrients moisture grain. This ex...

Understanding the physiological changes associated with high grain yield and high N use efficiency (NUE) is important when increasing the plant density and N rate to develop optimal agronomic management. We tested the hypothesis that high plant densities resulting in crowding stress reduce the ability of plants to use the N supply post-silking, thus decreasing the grain yield and NUE. In 2013 a...

The fluxes of (1) exogenous nitrogen (N) assimilation and (2) remobilization of endogenous N from vegetative plant compartments were measured by 15N labeling during the seed-filling period in pea (Pisum sativum L. cv Cameor), to better understand the mechanism of N remobilization. While the majority (86%) of exogenous N was allocated to the vegetative organs before the beginning of seed filling...

in order to investigate the contribution of ear photosynthesis and cytokinin in determining grain sink size, a pot study was conducted during january to june 2005 in cereal glasshouse of faculty of agriculture of karaj, iran. experiment was conducted in a complete randomized design with a factorial arrangement of two factors, three replications and four pots in each plot. factors included culti...