Gill epithelium of an angler catfish,Chaca chaca (Siluriformes,Chacidae): Enzyme and glycoprotein histochemistry

A series of histochemical techniques have been employed to localize alkaline phosphatase, acid phosphatase, non-specific esterase, catalase and peroxidase; and to visualize and characterize glycoprotein (GPs) moieties in the epithelium of gill arch, gill filaments and secondary lamellae of an angler catfish Chaca chaca. The epithelium of gill arch and gill filament shows strong alkaline phosphatase activity in the deeper layer epithelial cells; strong non-specific esterase activities in the outer layer epithelial cells; and weak acid phosphatase activity throughout the epithelium. The activity of these enzymes in the secondary lamellae is weak. The catalase and peroxidase show strong activities in the blood cells of the secondary lamellae. Various classes of GPs have been identified and characterized in the mucous secretions of the gill epithelium of C. chaca. These include—GPs with oxidizable vicinal diols, GPs with sialic acid residues without O-acyl substitution and GPs with O-sulphate esters. The functional significance of different enzymes in gill epithelium and the GPs in the mucus secreted on the surface has been discussed with the physiology of the gills in relation to the characteristic habit and habitat of the fish.     

Population structure,gene flow and genetic diversity analyses based on agro-morphological traits and microsatellite markers within cultivated and wild germplasms of okra [Abelmoschus esculentus (L.) Moench.]

Genetic Resources and Crop Evolution - Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the...     

Screening of Yardlong bean (Vigna unguiculata (L.) Walp.ssp. unguiculata cv.-gr. sesquipedalis) genotypes for seed,yield and disease resistance traits

Genetic Resources and Crop Evolution - Yardlong bean genotypes have wide variability in seed coat colours. This study sought to screen of yardlong bean genotypes based on seed coat colour,...     

Seed inoculation with <Emphasis Type="Italic">Bacillus</Emphasis> spp. improves seedling vigour in oil-seed plant <Emphasis Type="Italic">Jatropha curcas</Emphasis> L.

Jatropha (Jatropha curcas L.) is a non-edible oil-seed plant with adaptability to marginal semi-arid lands and wastelands. The Indian Government is promoting jatropha to reduce dependence on the crude oil and to achieve energy independence by the year 2012, under the National Biodiesel Mission. Selected strains of Bacillus spp., either supplemented with or without chitin, were tested for their ability to promote growth of jatropha seedlings in pot culture studies. The strains supported growth of jatropha seedlings up to 42 days after sowing. Among all strains, Bacillus pumilus (IM-3) supplemented with chitin showed over all plant growth promotion effect resulting in enhanced shoot length (113%), dry shoot mass (360%), dry root mass (467%), dry total plant mass (346%), leaf area (256%), and chlorophyll content (74%) over control. Treating seeds with strain IM-3 without chitin resulted in enhanced dry shoot mass (473%), dry total plant mass (407%), and chlorophyll content (82%). However, Bacillus polymyxa (KRU-22) with chitin supported maximum root length (143%). Either strain IM-3 alone or in combination with other promising strains could be promoted further for enhanced initial seedling growth of jatropha.     

Microbial biomass and its activities in salt-affected coastal soils

Seasonal fluctuations in salinity are typical in coastal soils due to the intrusion of seawater in the groundwater. We studied the effect of salinity on the microbial and biochemical parameters of the salt-affected soils of the coastal region of Bay of Bengal, Sundarbans, India. The average pH values and average organic C (OC) contents of soils from nine different sites cultivated with rice (Oryza sativa) ranged from 4.8 to 7.8 and from 5.2 to 14.1 g kg⁻¹, respectively. The average electrical conductivity of the saturation extract (EC_e) during the summer season was about five times higher than that during the monsoon season. Within the nine sites, three soils (S₃, S₄, and S₅) were the most saline. The average microbial biomass C (MBC), average basal soil respiration (BSR), and average fluorescein diacetate hydrolyzing activity (FDHA) were lowest during the summer season, indicating a negative influence of soil salinity. About 59%, 50%, and 20% variation in MBC/OC, FDHA/OC, and BSR/MBC (metabolic quotient, qCO₂), respectively, which are indicators of environmental stress, could be explained by the variation in EC_e. The decrease in MBC and microbial activities with a rise in salinity is probably one of the reasons for the poor crop growth in salt-affected coastal soils.     

Assessment of different methods of rice (Oryza sativa. L) cultivation affecting growth parameters, soil chemical, biological, and microbiological properties, water saving, and grain yield in rice–rice system

Field experiments were conducted at DRR farm located at ICRISAT, Patancheru, in sandy clay loam soils during four seasons, Kharif 2008, Rabi 2008–2009, Kharif 2009 and Rabi 2009–2010, to investigate growth parameters, water-saving potential, root characteristics, chemical, biological, and microbial properties of rhizosphere soil, and grain yield of rice (Oryza sativa L.) by comparing the plants grown with system of rice intensification (SRI) methods, with organic or organic + inorganic fertilization, against current recommended best management practices (BMP). All the growth parameters including plant height, effective tillers (10–45 %), panicle length, dry matter, root dry weight (24–57 %), and root volume (10–66 %) were found to be significantly higher with in SRI-organic + inorganic over BMP. With SRI-organic fertilization, growth parameters showed inconsistent results; however, root dry weight (3–77 %) and root volume (31–162 %) were found significantly superior compared to BMP. Grain yield was found significantly higher in SRI-organic + inorganic (12–23 and 4–35 % in the Kharif and Rabi seasons, respectively), while with SRI-organic management, yield was found higher (4–34 %) only in the Rabi seasons compared to BMP. An average of 31 and 37 % of irrigation water were saved during Kharif and Rabi seasons, respectively, with both SRI methods of rice cultivation compared to BMP. Further, total nitrogen, organic carbon%, soil dehydrogenase, microbial biomass carbon, total bacteria, fungi, and actinomycetes were found higher in the two SRI plots in comparison to BMP. It is concluded that SRI practices create favorable conditions for beneficial soil microbes to prosper, save irrigation water, and increase grain yield.     

Effect of Straw on Yield Components of Rice (Oryza sativa L.) Under Rice-Rice Cropping System

Field experiments were conducted at the Directorate of Rice Research experimental farm, ICRISAT campus, Patancheru, Hyderabad, during 1998–2000 for five consecutive seasons (three wet and two dry seasons) with five treatments [T1 – 100 % straw incorporation; T2 – 50 % straw incorporation; T3 – 100 % straw + green manure (GM) incorporation; T4 – 100 % straw burning and T5 – 100 % straw removal (control)] along with the recommended dose of fertilizers to evaluate the effect of different crop residue management (CRM) practices on yield components and yield of rice in rice–rice cropping sequence. The ammonium N measured at active tillering was higher in 100 % straw‐added plots over 50 % straw addition and straw removal with maximum values in the straw + GM‐incorporated plots. Among the yield components, tillers, panicles and spikelets were influenced from the second season of residue incorporation with significant increase in 100 % straw‐added treatments. The increase in tiller and panicle number could be attributed to the increased NH₄‐N in these treatments, which is evident from the significant correlation between tiller number and NH₄‐N (r = 0.82**) and panicle number and NH₄‐N (r = 0.87**). The influence of residue treatments on rice grain yield was observed from the third season onwards where incorporation of straw alone or in combination with GM and burning of straw significantly increased grain and straw yields. Grain yield showed significant positive correlation with the number of tillers (r = 0.74*–0.81**) and panicles (r = 0.74*–0.84**) in three treatments (T1, T3 andT4) where grain yields were significantly higher. The regression analysis showed that 57–66 % and 64–75 % of the variation in yield could be explained by tillers and panicles together in these three treatments during wet and dry seasons respectively. Thus, CRM practices such as addition of 100 % straw either alone or with GM and straw burning influenced the yield components (tillers, panicles and spikelets) positively and thereby increased rice grain yields.     

Cytoplasmic effects on photosynthesis and ribulose-1,5-bisphosphate carboxylase activity in Brassica species

Brassica genotypes representing four different species viz. B. nigra and B. campestris (both primary diploids), B. juncea and B. carinata (both allotetraploids) were examined for photosynthesis rate (Pn), ribulose-1,5-bisphosphate carboxylase (RuBPC) activity, leaf soluble protein and chlorophyll content. B. nigra is the male and female parent of B. juncea and B. carinata, respectively. B. campestris is the maternal parent of B. juncea. Pn was significantly higher in B. nigra and B. carinata compared to the other two species. These two species also sustained Pn of the leaves for a longer period during ontogeny. When B. nigra was the male parent, the higher Pn of B. nigra was not inherited in B. juncea. On the other hand, the Pn and pattern of ontogenetic changes in B. campestris and B. juncea were more or less similar. In specific RuBPC activity on soluble protein basis, chlorophyll and soluble protein content B. carinata also followed B. nigra whereas, B. juncea followed B. campestris. These results indicated the possible maternal(cytoplasmic) influence on the inheritance of these traits. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of Nitrogen on Dry Matter Accumulation and Productivity of Three Cropping Systems and Residual Effects on Wheat in Deep Vertisols of Central India

A field experiment was conducted on deep vertisols of Bhopal, India to study the effects of three levels of nitrogen (N), namely 0, 75 and 100 % of the recommended dose of nitrogen (RDN), on the dry matter accumulation (DMA) and productivity of three cropping systems (sole soybean, sole sorghum and soybean + sorghum intercropping) during the rainy season and their residual effect on the subsequent wheat crop during the post-rainy season. During the rainy season, sole sorghum was found to have significantly higher DMA and productivity in terms of soybean equivalent yield (SEY) than sole soybean or soybean + sorghum intercropping. Increasing the N dose from 0 to 100 % RDN significantly improved the DMA and SEY. At a low fertility level (N₀), soybean + sorghum intercropping was found to be more productive, while at a high fertility level (100 % RDN), sole sorghum was more productive than the other two cropping systems. However, during the post-rainy season, sole soybean as the preceding crop gave the highest DMA and seed yield of wheat, which were similar to those found with soybean + sorghum intercropping. Sorghum followed by wheat gave the lowest DMA and seed yield of wheat. Application of 100 % RDN irrespective of cropping system during the preceding crop improved the DMA of wheat but not its seed yield. However, N applied to the wheat crop significantly increased its DMA and seed yield.     

Contribution of Leaf Photosynthesis towards Seed Yield in Brassica species

The effect of defoliation after flowering, when a considerable number of pods were already formed on yield components, was examined in four Brassica species. In B. campestris and B. juncea , a decrease in seed yield by defoliation was associated with a decrease in the number of pods per plant as seed number per pod and thousand-seed weight were not significantly affected by this treatment. In B. nigra , apart from decreasing the pod number per plant, defoliation also significantly decreased the thousand-seed weight, Defoliation significantly decreased both seed number per pod and thousand-seed weight apart from decreasing the number of pods per plant in B. carinata. The study indicated that in B. campestris and B. juncea , the role of leaf photosynthesis seemed to be restricted mainly to the formation of pods. On the other hand, in B. nigra and B. carinata it appeared that leaf photosynthesis also contributed towards seed development.