Scientific analysis of indigenous techniques for guggal （Commiphora wightii） tapping in India

Guggal, a threatened species that is endemic to western India, is tapped to extract medicinally important oleo–gum–resin(guggul). However, the plant dies after gum exudation. The indigenous tapping techniques used by local people were examined in Gujarat, India to discover the scientific basis behind these techniques: selection of gum inducer, season of tapping, and plant parts to be tapped. First, the presence of Xanthomonas axonopodis pv. commiphorae(Xac) in the gum suspension used for tapping was established. This bacterium induces gum oozing from the tapped plants and later, causes them to die off. The population of Xac in gum was found to decrease with the age of the gum. With that, fresh gum increased the tapping success. Second, local people preferred tapping during the warm season, which we validated by determining that Xac growth was best at 30 °C. Tapping during September(mean temperature 25.7–30.0 °C) clearly favoured growth of the pathogen and yielded maximum guggul. Multiple tapping on a mature tree ensured maximum gum extraction before its death. Finally, application of indigenous technology under natural plant stands by the local people ensured availability of this important raw drug for consumption. Our study established that the age–old traditional methods have a strong scientific basis. However, it is imperative to formulate strategies based on contemporary scientific understanding to protect this natural resource before it becomes extinct.     

Effect of chemically modified date palm leaf fiber on mechanical,thermal and rheological properties of polyvinylpyrrolidone

Polyvinylpyrrolidone/date palm leaf fiber (PVP/DPL) biocomposites were prepared by melt mixing fabrication technique with different weight percentage of fibers. DPL fibers were chemically modified by acrylic acid in order to have better dispersion and compatibility with PVP matrix. The interaction of DPL fibers with PVP matrix was studied by Fourier transforms infrared spectroscopy (FTIR). Field emission scanning electron microscope (FESEM) was used for the study the morphology of chemically modified DPL fibers and PVP/DPL biocomposites. Mechanical properties were improved with fiber loading due to strong interfacial adhesion between PVP and DPL fibers. The storage modulus, loss modulus and tan delta values of PVA/DPL biocomposites were measured by DMTA. The rheological properties were investigated to study the shearing storage and loss modulii along with complex viscosity of biocomposites. The thermal and conducting properties of biocomposites were measured and compared with that of virgin PVP.     

Estimation of gut contents of freshwater mussel, Lamellidens marginalis L.

This study examined the food organisms found in the gut of freshwater mussels, Lamellidens marginalis L. A total of 34 taxa of food organisms were recorded, out of which 30 taxa belonged to phytoplankton and four taxa to zooplankton. Both the groups comprised three families each: Cyanophyceae (blue‐green algae), Chlorophycea (green algae) and Bacillariophyceae (diatoms) constituted phytoplankton, whereas Euglenaceae, Chlamydodontidae and Brachionidae belonged to zooplankton. The total number of frequencies of phytoplankton (n=537) were almost nine times more than that of zooplankton (n=60). When blue‐green algae, green algae, diatoms and zooplankton (all the three families together) were tested for significant difference (P<0.05) following Duncan's multiple range test, the result showed only two groups. Blue‐green algae, green algae and zooplankton were not significantly different (P<0.05), forming group A, whereas diatoms were significantly different from others, forming group B. The present study showed that the maximum number of organisms that mussels feed upon belong to green algae, followed by diatoms, blue‐green algae and few taxa of zooplankton.     

Identification of a diverse mini‐core panel of Indian rice germplasm based on genotyping using microsatellite markers

Identification of a small core germplasm set representing the available genetic diversity is essential for its proper evaluation and subsequent utilization in rice improvement programmes. For constituting a small diverse mini‐core panel of Indian rice germplasm, a representative set of 6912 accessions drawn based on their geographic origin from the whole rice germplasm collection available in the National Gene Bank was genotyped using 36 microsatellite markers. Automated fragment analysis of amplicons yielded a total of 435 alleles, with an average 12.4 and range of 3–29 alleles per locus. Polymorphism information content (PIC) ranged from 0.08 (RGNMS190) to 0.86 (RM552) with an average of 0.528. Based on genotyping data, a mini‐core consisting of 98 genotypes was identified. Ninety‐four per cent of the alleles present in the core set were present in the mini‐core. The identified small but diverse panel will be useful for further intensive trait‐specific evaluation and utilization in allele mining.     

Population status and regeneration of a tropical clumping bamboo <Emphasis Type="Italic">Schizostachyum dullooa</Emphasis> under two management regimes

Schizostachyum dullooa (Gamble) Majumder ‘dolu bamboo’ is a thin walled sympodial moderate sized to large tufted bamboo, dominant in the successional fallows of northeast India. The impact of resource management on productivity and sustainability of the species was evaluated by investigating the population status and regeneration in Cachar tropical semi evergreen forest under private property resource management (PPRM) and common property resource management (CPRM) regimes. Population status revealed current-year, one-year, two-year and three-year-old culms contribute 54%, 24%, 16% and 6% of the total culms per clump, respectively, under PPRM. Three-year-old culms were absent in CPRM and population status was thus represented by current year (83%), one-year (16%) and two-year (1%) old culms. Net change, rate of change and % gain in population for different age classes showed the prevalence of management practices under CPRM was unscientific. Efficiency of new culm production per clump used as an index of regeneration was 69.7% in PPRM and 59.88% in CPRM. New culms produced under CPRM were small and thin. We conclude that CPRM is inappropriate for a long term economic and ecological sustainability of the species and alternative management protocols are needed for conservation of the species.     

Morphological, anatomical and molecular investigation into witches’ broom disease of mamejvo (Enicostemma axillare)

Mamejvo (Enicostemma axillare Raynal) is a perennial herb with diversified health benefits. It was found to be affected by a witches?? broom disease under the field conditions at Anand, Gujarat, India. Affected plants were 53.33% reduced in height due to shortened internodes, leading to typical witches?? broom symptoms. Flower size was reduced significantly in the affected plants compared with the healthy ones and their petal color gradually turned green (virescence). Affected plants produced 2.5 times more dry herbage than the normal plants but with less active ingredient (swertiamarin). Symptomatic plants died early while root suckers from such plants failed to establish after transplanting. DAPI stained transverse sections of affected shoot tips showed the presence of discrete greenish fluorescence in the phloem cells under UV light. Amplification of 1.2?kb phytoplasma specific rDNA fragment from diseased tissue confirmed the presence of the pathogen. Further characterization of the pathogen through virtual rDNA?CRFLP pattern and rDNA sequence based phylogeny suggested that the pathogen, Enicostemma witches?? broom phytoplasma, belonged to 16SrII?CC group of ??Ca Phytoplasma aurantifolia??.