Effects of light intensity and plant size on the foliar nutrient content of field‐grown metrosideros polymorpha seedlings

Foliar concentrations of eight essential elements were measured in three sizes of Metrosideros polymorpha tree seedlings that had been subjected to five different light levels as part of a canopy thinning experiment in a Hawaiian montane rain forest. Most element concentrations were reduced by increased light intensity, but this was statistically significant only for Ca, Mg, and Zn. N and P concentrations markedly decreased with increasing plant size. No element exhibited consistent concentration increases in response to higher light or greater size. As in temperate herbaceous species, lower element concentrations associated with larger or more illuminated plants may represent a dilution effect related to the cumulative amount of C fixed in the lifetime of individual leaves. The rapid growth of newly unshaded seedlings may result in nutrient limitations in seedlings not rooted in mineral soil.     

Limited contribution of water availability in genotype-by-environment interaction in sugarcane yield and yield components

Water deficit is an important abiotic stress factor limiting sugarcane production. Understanding the effect of water deficit on cane yield, yield components and genotype × environment (G × E) interaction can aid in selecting genotypes that are adapted to water deficit conditions. In this study, response of cane yield and yield components of 10 sugarcane genotypes grown under 3 irrigation treatments—fully irrigated, semi-irrigated and rainfed—was examined across 3 locations and 3 crop-years within each location. Cane yield reduced by 32% and 9% in the rainfed and semi-irrigated treatments, respectively, compared to the fully irrigated treatment. Genotypic variation was highly significant for cane yield and yield components in all three irrigation regimes. Cane yield in the rainfed treatment showed significant genetic correlation with stalk diameter (r_g = 0.68), leaf number (r_g = 0.64), node number (r_g = 0.67) and stalk number (r_g = 0.68). Genotype × irrigation variance was negligible compared to genotype, genotype × location and genotype × crop-year variances. Commercial genotypes had higher yield in most environments except in low-yield potential environments, which caused a significant genotype × location × irrigation effect, suggesting opportunities for improving sugarcane productivity in these environments.     

Viral infections in cultured fish and shrimps: current status and treatment methods

Aquaculture is growing post-haste in recent years particularly in the fish and shrimp production. The rapid growth of aquaculture and increasing demand for fish have led to a rapid development of the fish and shrimp industry, resulting in increased production of both fish and shrimps. As a result, there is a greater risk of disease outbreaks. Mass mortalities in aquaculture are primarily due to infectious diseases caused by bacteria, viruses, and fungi. Among them, viral diseases are the most devastating, causing huge loss in the production of both cultured fish and shellfishes. There are several effective methods of treatment for these disease outbreaks. This review focuses on various methods of controlling the viral pathogens using various treatment methods like use of medicinal plants and seaweed extracts, bioactive compounds from actinomycetes, vaccines, probiotic microbes, chemicals, nanoparticles, and green synthesis of nanoparticles.

     

Ozone and temperature trends associated with the 11-year solar cycle

Evidence is presented which suggests that trends in the ozone concentration and stratospheric temperature, reported between the early 1960's and 1976, are to a large extent due to solar ultraviolet flux variability associated with the 11-year solar cycle. Radiative-convective-photochemical simulations of ozone and temperature variations have been made with a solar ultraviolet flux variability model. Results for temperatures and ozone concentrations, when compared with published data, show good agreement.     

Biophysical and socio‐economic causes for increasing fallow land in Tamil Nadu

The question of increasing fallow land assumes significance at national and international levels due to the decline in net cultivated area and increasing population. Biophysical characteristics of farmland and socio‐economic conditions of farmers are responsible for the increasing fallow. This study was carried out to assess the extent of permanent fallow and identify causes for its increase. High‐resolution remote sensing data were used to identify fallow land in two identified blocks of south India, viz. Nanguneri and Kangeyam. The land resources were characterized, and the specific biophysical and socio‐economic factors responsible for the increasing fallow land were assessed. Multiple regression analysis was carried out to identify the factors responsible for increasing fallows. Soil parameters such as erosion, soil texture, soil depth and available nitrogen contributed significantly (P > 0.05) to the increase in fallow land. The size of farm holding, number of farm fragments, distance from the road in Nanguneri and farm size and the distance to the nearest town in Kangeyam were socio‐economic factors that had a strong effect (P > 0.01) on increasing the fallow land. Variable importance rankings in random forest analysis indicated that soil erosion and soil pH had the largest impact on the decision to fallow land in Nanguneri and Kangeyam blocks, respectively. Based on biophysical and socio‐economic constraints, the land resources of fallow land were evaluated for other alternate land use options and policy measures were suggested.     

Effect of six decades of selective breeding on soybean protein composition and quality: a biochemical and molecular analysis

To evaluate the extent of the genetic change and its effects on the seed protein composition of soybean cultivars released during the past 60 years, representative ancestral cultivars and those derived from selective breeding were grown in a side-by-side comparison. Total seed protein content, determined by combustion analysis of nitrogen, revealed a decline in the protein content after decades of selection and breeding. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis comparison of protein profiles of the soybean cultivars indicated that relative expression of most of the seed storage proteins had not varied substantially from the ancestral lines to the present commercial cultivars. There was noticeably less beta-subunit of beta-conglycinin, a protein devoid of sulfur amino acids, in the modern cultivars represented by Mustang, Pioneer 93B09, and Asgrow 3602. Comparison of the amino acid profiles of soybean seed, a benchmark of the protein's nutritional quality, revealed that the ancestral progenitor, G. soja, was significantly higher in cysteine, glutamic acid, histidine, and arginine than either the ancestral or the modern cultivars. Selective breeding over the past 60 years minimally affected the overall amino acid composition. The degree of divergence in the DNA sequence of the genes encoding glycinin and beta-conglycinin in the ancestral and modern cultivars was investigated using Southern hybridization and the polymerase chain reaction. Even though some restriction fragment polymorphisms could be detected, overall, the banding patterns were remarkably similar among the ancestral cultivars and those derived from them, suggesting a high degree of conservation of seed-storage protein genes. The results of our study suggest that selection and breeding for yield during the past 60 years had no major influence on the protein composition, ostensibly because of limited genetic diversity among the parental lines.     

Chemical composition and antioxidant capacity of the aqueous extract of Phellodendron amurense

The aqueous extract of Phellodendron amurense Rupr.(Amur Cork Tree) provides a rich source of antioxidants and chemical compounds, and can be used for food and wood preservative materials.In this study, we characterized the chemical composition of this extract by GC and GC/MS.The antioxidant capacity was evaluated using a variety of antioxidant assays(superoxide radical,hydroxyl radical, nitric oxide radical, and DPPH radical scavenging activity).Additionally, total polyphenolic content was determined.Phenolic acids and acetone derivatives were major compounds of the extract capable of scavenging the DPPH free radical and reducing ferric ions.DPPH and ferric ion reduction results were strongly correlated with total phenolic content of the extract which also exhibited strong nitric oxide, hydroxyl radical scavenging and superoxide anion radical scavenging activities.     

Chemical composition and antioxidant capacity of the aqueous extract of <Emphasis Type="Italic">Phellodendron amurense</Emphasis>

The aqueous extract of Phellodendron amurense Rupr. (Amur Cork Tree) provides a rich source of antioxidants and chemical compounds, and can be used for food and wood preservative materials. In this study, we characterized the chemical composition of this extract by GC and GC/MS. The antioxidant capacity was evaluated using a variety of antioxidant assays (superoxide radical, hydroxyl radical, nitric oxide radical, and DPPH radical scavenging activity). Additionally, total polyphenolic content was determined. Phenolic acids and acetone derivatives were major compounds of the extract capable of scavenging the DPPH free radical and reducing ferric ions. DPPH and ferric ion reduction results were strongly correlated with total phenolic content of the extract which also exhibited strong nitric oxide, hydroxyl radical scavenging and superoxide anion radical scavenging activities.