Nitrogen Use Efficiency Phenotype and Associated Genes: Roles of Germination, Flowering, Root/Shoot Length and Biomass.

Crop improvement for Nitrogen Use Efficiency (NUE) requires a well-defined phenotype and genotype, especially for different N-forms. As N-supply enhances growth, we comprehensively evaluated 25 commonly measured phenotypic parameters for N response using 4 N treatments in six indica rice genotypes. For this, 32 replicate potted plants were grown in the green-house on nutrient-depleted sand.

Phenotyping for Nitrogen Use Efficiency: Rice Genotypes Differ in N-Responsive Germination, Oxygen Consumption, Seed Urease Activities, Root Growth, Crop Duration, and Yield at Low N.

The biological improvement of fertilizer nitrogen use efficiency (NUE) is hampered by the poor characterization of the phenotype and genotype for crop N response and NUE. In an attempt to identify phenotypic traits for N-response and NUE in the earliest stages of plant growth, we analyzed the N-responsive germination, respiration, urease activities, and root/shoot growth of 21 Indica genotypes of rice ( var. ).

Respiration hastens maturation and lowers yield in rice.

Role of respiration in plant growth remains an enigma. Growth of meristematic cells, which are not photosynthetic, is entirely driven by endogenous respiration. Does respiration determine growth and size or does it merely burn off the carbon depleting the biomass? We show here that respiration of the germinating rice seed, which is contributed largely by the meristematic cells of the embryo, quantitatively correlates with the dynamics of much of plant growth, starting with the time for germination to the time for flowering and yield.

The alternative oxidase mediated respiration contributes to growth, resistance to hyperosmotic media and accumulation of secondary metabolites in three species.

Plant respiration, similar to respiration in animal mitochondria, exhibits both osmosensitive and insensitive components with the clear distinction that the insensitive respiration in plants is quantitatively better described as 'less' sensitive rather than 'insensitive'. Salicylic hydroxamic acid (SHAM)-sensitive respiration was compared with the respiration sensitive to other inhibitors in rice, yeast and Dunaliella salina. The influence of SHAM was largely in the osmotically less sensitive component and enhanced with external osmotic pressure unlike other inhibitors that inhibited the osmotically sensitive component.

Shape anisotropy of lipid molecules and voids.

Biological polymers, viz., proteins, membranes and micelles exhibit structural discontinuities in terms of spaces unfilled by the polymeric phase, termed voids. These voids exhibit dynamics and lead to interesting properties which are experimentally demonstrable.