Relative Contribution of Nitrogen Absorption, Remobilization, and Partitioning to the Ear During Grain Filling in Chinese Winter Wheat.

Knowledge of the function of the ear as a key organ in the uptake, remobilization and partitioning of nitrogen is essential for understanding its contribution to grain filling and thus guiding future breeding strategies. In this work, four Chinese winter wheat genotypes were grown on a 15N-enriched nutrient solution. N absorption and further remobilization to the flag leaf, the ear and the mature grains were calculated via the 15N atom % excess. The results indicated that the high yields of the Chinese wheat genotype were determined by higher grain numbers per ear, with greater plant height and a larger ear size, while the thousand-grain weight did not affect grain yield. In the mature grains, 66.7% of total N was remobilized from the pre-anthesis accumulation in the biomass, while the remaining 33.3% was derived from the N taken up during post-anthesis. From anthesis to 2 weeks after the anthesis stage, the flag leaf remobilized 3.67 mg of N outwards and the ear remobilized 3.87 mg of N inwards from the pre-anthesis accumulation in each plant. The positive correlation between ear Nrem and grain Nrem indicated that the ear was an important organ for providing N to the grain, whereas the remobilized N stream from the leaves was not correlated with grain Nrem, thus indicating that flag leaf N was not translocated directly to the grain. The grain Nrem was negatively correlated with the ear N concentration throughout grain filling, which suggested that higher-yielding genotypes had better sink activity in the ear, while Rubisco played a critical role in N deposition. Therefore, to improve yield potential in wheat, the N accumulation in the ear and the subsequent remobilization of that stored N to the grains should be considered. N accumulation and remobilization in the ear may at least be valuable for Chinese breeding programs that aim at optimizing the sink/source balance to improve grain filling.

Report: Phytochemical screening and antimicrobial activities of red silk cotton tree (Bombax ceiba L.).

The present study was conducted to investigate the phytochemical screening and antimicrobial activities of stem bark of Bombax ceiba L. The methanol extract was subjected to qualitative phytochemical screening using standard procedures. The results indicated the presence of alkaloids, tannins, glycosides, reducing sugar, saponins, phlobatanins and terpenoids. The antimicrobial activity was measured by disc diffusion method. Data revealed that Pseudomonas aeruginosa was inhibited by both methanol and ethanol extracts at the concentration of 2mg disc-1 {21.8mm (68.12%) and 21.3mm (66.56%)}. Similarly, methanol extract reduced the growth of Bacillus subtilis by 17.1mm (74.34%) at the concentration of 1 mg disc-1. However, ethanol extract showed a good activity of 18mm (121.6%) and 20.6mm (112.5%) against Xanthomonas maltophilia at concentrations of 1 and 2 mg disc-1, respectively. Aqueous extract showed 16 mm (53.33% Z.I) against Escherichia coli at 2 mg disc-1. Klebsiella pneumoniae was found resistant to all of the three extracts, while the growth of Candida albicans was inhibited by methanol through 16.5 mm (58.92% Z.I) at 1 mg disc-1. The above study concluded the medicinal potential of B. ceiba.