The study revealed a new species of Polucoccum colonising thallus of lichen genus Lepra and Varicellaria in tropical and temperate regions of India. The genus belonging to the family Polycoccaceae is represented by 7 species in India. Though the genus is host-specific, there are 12 genera of lichens which are home for more than one species of this fungus. It is the second known species of Polucoccum on members of Lepra and Varicellaria, and differs from the previously known ones – 1) Polucoccum ochvarianum by being gall forming and having smaller perithecia [(88-)104-128-152(−170) × (81-)95-114-133(−145) μm] and 2) Polucoccum sp. in having smaller perithecia [op. cit. vs. 250-300 μm], hymenial gelatine I-, and smaller asci [(50-)55-60-65(-75) × (10-)13-15-17(-18) vs. 90 × 14 μim].
Assessment of the qualitative losses in different varieties of sorghum following
Walker infestation revealed the significant decrease
dry matter digestibility of whole plant, leaves and stem by about 6.0, 3.5 and 3.0 per cent, respectively at more than 60 per cent infestation level and was mainly due to the corresponding increase in tannin content. The fibre components (NDF and ADF) were acting as an additional factor in reducing the dry matter digestibility. The dry fodder yield was also reduced by 46 to 53 per cent in different varieties of sorghum with an increase in infestation level from 0 to >60 per cent. The stem of all the varieties was more fibreous than the leaves as it had high content of NDF, ADF, cellulose and lignin. Leaves on the other hand had high amount of protein, total soluble sugars and reducing sugars than stem and were therefore more digestible than stem.
The phenolic profile and specific activity of oxidative enzymes in sorghum leaves and stem resistant and susceptible to
(Swinhoe) were analyzed at 45 and 60 days after germination. Resistant varieties had higher content of total phenols, o-dihydric phenols, flavanols and tannins than the susceptible varieties at both the stages of plant growth and the concentration of these biomolecules increased after infestation as well as with plant age in both sets of varieties. Moreover, resistant varieties exhibited higher specific activity of polyphenol oxidase, peroxidase, phenylalanine ammonia-lyase and tyrosine ammonia-lyase in their leaves and stem in comparison to the corresponding activities in susceptible ones. Peroxidase activity was several folds than the polyphenol oxidase. Healthy leaves of susceptible varieties showed higher catalase activity in comparison with resistant ones at day 45 and this trend was reversed at day 60. Role of phenolic compounds and oxidative enzymes particularly the peroxidase in determining resistance against stem borer has been high lighted.
Authors:Y. Sharma, S. N. Sharma, P. Joshi, and R. S. Sain
The F1 and F2 progenies of a ten-parent diallel cross (excluding reciprocals) were analysed for the combining ability of quantitative traits in six-rowed barley (Hordeum vulgare L.). significant differences were indicated between the parents, F1s and F2s for all the characters studied. The gca and sca components of variance were significant for all the traits. Both additive and non-additive gene effects were involved in the genetic control of the characters; however, non-additive gene effects were observed to be predominant. Among the parents RD 2035, RD 2052, RD 2503 and BL 2 were the best general combiners for grain yield and average to high combiners for other important traits.The parents RD 2552 and RD 387 were the best general combiners for dwarfness. The best specific crosses for grain yield were RD 2503 × RD 2585,RD 2035 × RD 2052, RD 2035 × BL 2, RD 2052 × BL 2, RD 2508 × RD 2552, RD 2552 × RD 2585 and Rd 2052 × RD 2552 in both the F1 and F2 generations. These crosses were higher yielders and in most of the crosses one of the parents involved was a good combiner, indicating that such combinations can be expected to produce desirable transgressive segregants. All the best crosses for grain yield also showed average to high sca effects for most of the yield components. Most of the specific crosses for grain yield involved high × average, average × average and average × poor general combiners. To ensure a further increase in grain yield, the combination of desirable yield components is advocated. The inclusion of F1 hybrids showing high sca, and having parents with good gca, in multiple crosses, bi-parental mating or diallel selective mating could prove a worthwhile approach for further amelioration of grain yield in six-rowed barley.
Thermal behavior of aqueous hydroxypropylmethylcellulose (HPMC)/surfactant mixtures was studied in the dilute concentration
regime using micro-differential scanning calorimetry (DSC). The surfactant used was sodium n-dodecyl sulfate (SDS). The heat capacity of HPMC gel with various concentrations of SDS was much higher than that of the
pure HPMC gel. The addition of SDS at different concentrations showed dissimilar influences on the gelation of HPMC; SDS at
lower concentrations (≤6 mM) did not affect gelation temperature significantly except for enhancing the heat capacity whilst
SDS at higher concentrations (≥6 mM) not only resulted in the gelation of HPMC at higher temperatures but also changed the
pattern of the gelation thermograph from a single mode to a bimodal. On the basis of the observed thermal behavior of HPMC/SDS
systems, the mechanism behind the sol-gel transition was discussed in terms of the properties of the surfactant and their
influences on the extent of polymer/surfactant binding and polymer/polymer hydrophobic association. Gelation kinetics was
analysed using the results from the DSC measurements. The kinetic parameters were determined.
Methylcellulose (MC) is a thermo-reversible physical hydrogel. This study investigates the thermodynamic characteristics of gelation mechanism for MC. The relative and absolute specific heat capacity values of the hydrogel system were modeled using an empirical formulation to facilitate calculation of thermodynamic parameters. Experiments verifying the assumptions for the model formulation were conducted and are discussed. Parameters such as enthalpy, entropy, and changes in their magnitude as a function of temperature were calculated and their trends were studied. The implications of these observations on the various stages of the gel formation process and the associated mechanisms are evaluated. The studies revealed that the gelation of MC is a temperature- driven process rather than only driven by the heat input, and it attains a state of equilibrium under isothermal conditions. During gelation, the entropy of the overall (MC+water) system increases due to an increase in the disorderliness of the MC system.
A new lichenicolous fungus Melaspilea nitidochapsae colonising on the thallus of Nitidochapsa leprieurii (Mont.) Parnmen, Lücking et Lumbsch is described from India. The new species differs from other known species colonising lichen family Graphidaceae by having completely carbonised exciple, hyaline to pale brown transversely 1-septate ascospores and a different host.
Authors:Y. Joshi, S. Upadhyay, K. Chandra, K. Bisht, and A. Falswal
A new gall-inducing and lirellate lichenicolous fungus, Plectocarpon diedertzianum Y. Joshi, Upadhyay et Chandra, is described from Kumaun Himalayan regions of India colonising thallus of various parmelioid lichens (Flavoparmelia caperata, Myelochroa aurulenta, Parmotrema crinitum, P. melanothrix, P. reticulatum, Punctelia subrudecta). The new species is characterised by black, epruinose rounded to lirellate ascomata with a carbonised surface and a ±thalline pseudomargin, as well as a carbonised, sterile stromatic tissue, 4-spored asci and 3-septate hyaline ascospores.