Quantification of organic carbon and primary nutrients in litter and soil in a foothill forest plantation of eastern Himalaya

The present study was an effort to understand the amount of litter fall and its subsequent decomposition and quantify the release of available nutrients and soil physicochemical characteristics in plantations of four forest tree species(Lagerstroemia parviflora, Tectona grandis, Shorea robusta and Michelia champaca) in the Chilapatta Reserve Forest of the Cooch Behar Wildlife Division in the Terai zone of West Bengal, India. The most litter(5.61 Mg ha~(-1))was produced by T. grandis plantation and the least(4.72 Mg ha~(-1)) by L. parviflora. The material turnover rate to the soil through decomposition from total litter was fastest during the first quarter of the year and subsequently decreased during the next two quarters. The material turnover rate was only 1 year, which indicates that more than90% of the total litter produced decomposed within a year.The available primary nutrient content in litter varied across the four plantations over the year. The plantations generally did not significantly influence the soil physical characteristics but did significantly influence the availability of primary nutrients and organic carbon at two depths(1–15 and16–30 cm) over the year. The availability of soil primary nutrients in the four plantations also increased gradually from the first quarter of the year to the third quarter and then decreased during the last quarter to the same level as in the first quarter of the year at both depths. The availability for soil organic carbon in the plantations followed a similar trend. The amount of litter produced and the material turnover in the soil in the different plantations differed, influencing the nutrient availability and organic carbon at the plantations. The amount of soil organic carbon was highest for T. grandis(2.52 Mg ha~(-1)) and lowest for L. parviflora(2.12 Mg ha~(-1)). Litter is the source of soil organic matter,and more the litter that is produced by the plantations, the higher will be the content and amount of soil organic carbon in the plantation.     

Non-target effect of herbicides: I. effect of glyphosate and hexazinone on soil microbial activity. Microbial population,and in-vitro growth of ectomycorrhizal fungi

The effects of two herbicides, glyphosate (as a 359 g litre^?1 SL) and hexazinone (as a 50gkg^?1 granule) on soil microbial population, carbon dioxide evolution, and in-vitro growth of five species of ectomycorrhizal fungi were investigated. Glyphosate at 0–54 and 3.23 kg a.i. ha^?1 and hexazinone at 1. 2 and 8 kg a.i. ha^?1 did not reduce soil microbial population or carbon dioxide evolution in the long term (6 months). However, there was a significant short-term (2 months) effect of glyphosate on both fungal and bacterial counts at the 0.54 kg ha^?1 treatment. In in-vitro tests, Cenococcum graniforme. Hebeloma crustuliniforme and Laccaria laccata were more susceptible to both herbicides than was Suillus tomentosus. which was, in turn, more susceptible than Paxillus involutus. The growth of all five ectomycorrhizal fungi was significantly reduced when subjected to concentrations above 50 μl formulation litre^?1 (glyphosate) or 50 μg formulation litre^?1 (hexazinone).     

Development of sustainable performance index based on production,reproduction, health and longevity for genetic improvement of Sahiwal cattle

An attempt was made for the first time in India to develop the performance indices for quantifying the relative emphasis to be given to production, reproduction, health and longevity traits for selection and genetic improvement of Sahiwal cattle in a sustainable manner. The study was conducted using information related to various production, reproduction, health and longevity traits spread over a period of 29 years in Sahiwal cattle. Using income and expenditure method, the relative economic values for 305 days milk yield (305DMY), average daily milk yield (ADMY), calving to first insemination interval (CFI), days open (DO) and longevity (LNG) were estimated as 1, 1, −6.62, −6.62 and 5.96 in Sahiwal cattle. A total of three performance indices were constructed using three-trait combination, that is production, reproduction and longevity before and after excluding the days suffered by the animals. Correlation between the aggregate genotype and index (R_IH) was computed to determine the accuracy of each performance index, and based on highest R_IH value, best performance index was identified for selection of Sahiwal cattle. Developed indices were further assessed for robustness by increasing the relative economic values of the traits by 25% and 50%. The performance index (305DMY, DO and LNG) was found to be the best index before as well as after excluding days suffered by the animals, but in later case emphasis to be given to different traits was found to be more balanced. The best index indicated that about 47, 42 and 11% relative emphasis to be assigned to 305 days milk yield, days open and longevity for selection of Sahiwal animals for sustainable genetic improvement.     

Effect of fertilization on growth and ectomycorrhizal development of container-grown and bare-root nursery conifer seedlings

The effect of three levels of fertilizer on thegrowth of three species of containerized-grownconifer seedlings (Pinus contorta, Picea glauca, and Picea mariana) and twospecies of bare-root conifer seedlings (Pinus sylvestris and Larix sibirica),and on the colonization of these seedlings bysix species of ectomycorrhizal fungi (Hebeloma longicaudum, Laccaria bicolor,Paxillus involutus, Pisolithustinctorius, Rhizopogon vinicolor andSuillus tomentosus), was studied. Thegrowth of the seedlings in both container-grownand bare-root nurseries increased as the levelsof fertilizer increased. For better seedlinggrowth and environmental quality it may be possible to reduce the level of fertilizers in commercial nurseries upto 33% by using selected mycorrhizal fungi.Ectomycorrhizal colonization in all seedlingswas not affected by fertilizer levels. Hebeloma longicaudum, L. bicolor, P.involutus, and P. tinctorius formedwell-developed ectomycorrhizae, whereasectomycorrhizal development by R.vinicolor and S. tomentosus was poor.Native mycorrhizal fungi colonizednon-inoculated control seedlings; however,their colonization was always lower than withinoculated fungi.     

Studies in Forest Pathology

A survey for the parasitic alga. Cephaleuros virescens Künze in relation to its seasonal distribution in different forest types has been done. The alga was absent in gymnosperms and was common in angiosperms. The disease severity was more in summer and the rainy season and absent in winter, Combretum decandrum was found to be most susceptible to this parasite alga. Altogether 49 hosts were recorded out of which 26 were new host records. Healthy leaves contain higher amounts of total nitrogen and total phenol, whereas in algal infected leaves the amounts of total sugar, total amino acid and dry weight were higher.     

Effect of three species of bacteria on damping-off,root rot development,and ectomycorrhizal colonization of lodgepole pine and white spruce seedlings

Interactions between three species of bacteria (Burkholderia cepacia, Pseudomonas chlororaphis and Pseudomonas fluorescens), an ectomycorrhizal fungus (Paxillus involutus), and three root pathogenic fungi (Fusarium moniliforme, Fusarium oxysporum and Rhizoctonia solani) were studied. Burkholderia cepacia significantly reduced the in vitro mycelial growth of P. involutus, whereas, B. cepacia, Ps. chlororaphis, Ps. fluorescens and P. involutus reduced the mycelial growth of F. moniliforme, F. oxysporum and R. solani. Culture filtrates of B. cepacia, Ps. chlororaphis, Ps. fluorescens and P. involutus reduced conidial germination and increased the formation of chlamydospores of F. moniliforme and F. oxysporum. Burkholderia cepacia also reduced the formation of ectomycorrhizal short roots by P. involutus on lodgepole pine (Pinus contorta) and white spruce (Picea glauca) seedlings 2 months after inoculation. However, no significance difference in mycorrhizal short roots was observed after 4 months. The fungicide Anchor (a mixture of carboxine and thiram) significantly reduced root rot severity and increased the survival of lodgepole pine seedlings grown in a growth mix infested with F. moniliforme, F. oxysporum and R. solani. Control of the diseases of white spruce caused by these pathogens was not as successful. Treatment of seeds with either B. cepacia or P. involutus alone significantly increased the survival of seedlings grown in a mix that was inoculated with F. moniliforme and reduced the root rot severity caused by F. moniliforme and F. oxysporum, but not R. solani. Higher seedling survival and lower root rot severity were observed when conifer seeds were concomitantly inoculated with one of the bacterial species, P. involutus and Anchor.     

Role of Phialemonium curvatum as a potential biological control agent against a blue stain fungus on aspen

Ophiostoma crassivaginatum is the most important blue stain fungus on Populus tremuloides and causes considerable reduction in the value of the end product. The effect of a hyphomycetous fungus, Phialemonium curvatum, on the in vitro growth and wood chip colonization by O. crassivaginatum was studied. The in vitro growth of O. crassivaginatum was significantly inhibited when grown in dual culture or when treated with culture filtrate of P. curvatum. Ophiostoma crassivaginatum failed to colonize P. tremuloides wood chips when they were pre-inoculated with mycelial suspension of P. curvatum. The potential use of P. curvatum as a biological control agent against O. crassivaginatum is suggested.     

Live attenuated malaria vaccine designed to protect through hepatic CD8⁺ T cell immunity

Our goal is to develop a vaccine that sustainably prevents Plasmodium falciparum (Pf) malaria in ≥80% of recipients. Pf sporozoites (PfSPZ) administered by mosquito bites are the only immunogens shown to induce such protection in humans. Such protection is thought to be mediated by CD8(+) T cells in the liver that secrete interferon-γ (IFN-γ). We report that purified irradiated PfSPZ administered to 80 volunteers by needle inoculation in the skin was safe, but suboptimally immunogenic and protective. Animal studies demonstrated that intravenous immunization was critical for inducing a high frequency of PfSPZ-specific CD8(+), IFN-γ-producing T cells in the liver (nonhuman primates, mice) and conferring protection (mice). Our results suggest that intravenous administration of this vaccine will lead to the prevention of infection with Pf malaria.     

Interlayer tunneling and gap anisotropy in high-temperature superconductors

A quantitative analysis of a recent model of high-temperature superconductors based on an interlayer tunneling mechanism is presented. This model can account well for the observed magnitudes of the high transition temperatures in these materials and implies a gap that does not change sign, can be substantially anisotropic, and has the same symmetry as the crystal. The experimental consequences explored so far are consistent with the observations.