RELATIONSHIP BETWEEN SUGAR MAPLE DECLINE AND CORRESPONDING CHEMICAL CHANGES IN THE STEM TISSUE

Wood cores were taken at breast height of mature sugar maple (Acer Saccharum Marsh.) trees of approximately the same age from four sites in Ontario, Canada differing in soil characteristics and general tree health. The soils of two of the sites were acidic (podzols), while the soils of the other two sites were calcareous (brunisols). Selected elemental analyses using Neutron Activation Analysis were conducted on the soils and the xylem wood of the sugar maple trees, and the results were compared relative to tree health. Aluminum in stem xylem was found to be significantly higher in declining trees (mean 7.7 ppm) relative to the healthy trees (mean 4.0) from the acidic sites, where aluminum was freely available in the soil. Soil extractable aluminum was also significantly higher in the soil adjacent to the declining trees (mean 5.10) compared to the healthy trees (mean 3.20). These results show that xylem aluminum contents reflect the increased availability of aluminum in acidifying soils and provide additional evidence that dendrochemistry may be used as a proxy environmental monitoring tool.     

Carbon and water footprints of major crop production in India

Scarcity of water and emission of greenhouse gases (GHGs) are the two key environmental issues affecting crop production in India.Reducing the carbon footprint (CF) and water footprint (WF) of crop production can help to mitigate the environmental hazards that stem from GHG emissions and water scarcity.The CFs and WFs of three major cereal crops,rice,wheat,and maize,were estimated for the year 2014 under the environmental conditions in India,based on national statistics and other data sources.To...     

Detection of Peronospora manshurica (Naum.) Syd. in Seeds of Soybean, Glycine max

Out of 140 soybean samples tested from 17 countries, 42 originating from Brazil, Colombia, Iran, Korea, Malaysia, Thailand and the United States were found to be contaminated by oospores of Peronospora manshurica (Naum.) Syd. Oospores are generally present as a crust on the seed coat, and are easily detected during visual examination; however, individual spores may stick to the surface of non-crusted seed, and these spores are detectable only by examining surface washings.
A new method for testing the viability of oospores by the tetrazolium chloride test is described. Viable oospores turn orange-red. In all oospore collections, viability tested by this method was generally higher than germination recorded in water. One to 2-year-old oospores showed 30 to 39% viability, while an 8-year-old collection had about 20% viable spores. Oospores collected from 1-year-old seed treated with captan showed 6 to 11 % viability.