In vitro antimicrobial activities of different solvent extracted samples from Iris germinica

Antibacterial and antifungal activities of different solvents extracted samples of Iris germinica were carried out through disc diffusion assay. For this purpose five different solvent extracts were prepared with two concentrations [1 and 2 mg disc[-1]] and their antimicrobial activity was tested using disc diffusion assay against eight pathogenic bacteria viz. Staphylococcus aureus, B. subtilis, Bacillus atrophaeus, Escherichia coli, Pseudomonas aeruginosa, Erwinia carotovara, Klebsiella pneumoniae, Salmonella typhi and one fungal specie [Candida albicans]. Butanol and ethyl acetate fraction were more effective to control the growth of different pathogens followed by chloroform, hexane and aqueous fractions respectively. C. albicans, S. aureus E. carotovara, B. atrophaeus and E. coli were comparatively susceptible inhibited by all extracts of I. germinica compared with the rest of microbes. Maximum activity was shown by ethyl acetate extracted samples against B. atrophaeus followed by the same solvent against E. carotovara. Butanol extracted samples were effective against B. subtilis showing 62% reduction in growth at 1 or 2mg disc[-1] concentration. From these results it can be concluded that different solvent extracted samples from the leaves of I. germinica possess varying degree of antimicrobial against different micro-organisms and can be a good sources of antibiotics for the treatment of certain bacterial and fungal diseases

Effect of seedling age and water depth on morphological and physiological aspects of transplanted rice under high temperature / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

To study the effect of high temperature, rice seedlings 20, 30, 40 and 50 d were kept at 5, 10, 15 and 20 cm water depth in a water pool. Meteorological findings indicated that water temperature varied up to 10 cm but became stable below this depth. Deep water inflicted higher tiller mortality, minimal increase in dry weight of aerial parts and leaf area, decrease in root length, and decrease in root dry weight especially at 20 cm water depth and produced an unbalanced T/R ratio (top versus root dry weight). However, deep water tended to increase plant length. These parameters, however, excel in shallow water. Older seedlings, with the exception of root dry weight, could not perform well compared to young seedlings in all physiological and morphological aspects. The study revealed that seedlings, particularly young ones, stand well in shallow water and can cope with high temperature.