No abstract

ABSTRACT

The histopathological effects of monocrotophos on the gill, kidney and intestine tissues of the Cirrhinus mrigala were determined by light microscopy. The changes in the gills were characterized by epithelial hyperplasia, aneurysm, epithelial necrosis, desquamation, epithelial lifting, oedema, lamellar fusion and curling of secondary lamellae. Pycnotic nuclei in tubular epithelium, hypertrophied epithelial cells of renal tubules, contraction of the glomerulus and expansion of space inside the Bowman's capsule were observed in the kidney tissues of fish after exposure to monocrotophos. In the intestine tissues of fish exposed to monocrotophos, oedema, necrosis and atrophy of epithelial cells were observed.

Concentrations of Cu, Mn, Zn, Fe, Cr, and Pb were estimated using ICP-MS in nine commercially important and locally consumed fish species (Sarda orientalis, Scomberomorus commerson, Rastrelliger kanagurta, Sardinella longiceps, Paraplagusia bilineata, Cynoglossus lida, Cynoglossus macrostomus, Lepturacanthus savala, and Siganus javus) collected from coastal waters of Kalpakkam, eastern part of India. Their concentration (μg g(-1)) in the examined fish species ranged as follows: Cu (0.8-6.5), Zn (14.3-27.9), Mn (0.5-8.8), Fe (17.6-117.0), Cr (0.24-1.78), and Pb (0.18-2.29). Concentrations of most of the metals in the fish species studied were found to be safe for human consumption barring Mn.

It is well established fact that bacterial species promotes plant growth. This growth enhancing activity was believed to be through different mechanisms such as synthesis of phytohormones, nitrogen-fixing, and biological control. For this reason, in this present investigation we have isolated and identified Azotobacter spp. and Azospirillum spp. through macromorphologically and micromorphologically in order to assess its effect on growth and yield of strawberry (Fragaria vesca) an Albion variety in hydroponic system. The inoculation and coinoculation of bacterial culture was performed in combination with three nitrogen levels (50, 100 and 150 ppm), growth parameters such as plant height, root length, fresh and dry weight of root and aerial parts, leaf area, chlorophyll content, nutrient content, solid soluble, caliber, yield/plant. It is observed that in T8 (co-inoculation in100 ppm N) group showed significantly increase in plant height (18.57cm), chlorophyll content (48.57 Soil Plant Analysis Development-SPAD), fresh root weight (25.82g) and dry root weight (5.93g), while in treatment group T5 (Azotobacter spp. 100ppm of Nitrogen) and T6 (Azotobacter spp. 150ppm of Nitrogen) showed significant increase in root length, leaf area, dry and fresh weights of aerial parts. The N content of leaf for all treatments was in the ranges of 2.42 -2.83 % that is suitable for cultivation. Similarly, the treatment group T5 and T6 showed increase in yield per plant and soluble solids content. So, Azotobacter and Nitrogen treatment has growth related benefits in strawberries under hydroponic system.