Screening of vincristine yield in ex vitro and in vitro somatic embryos derived plantlets of Catharanthus roseus L. (G) Don.

Catharanthus roseus L. (G.) Don. (Apocynaceae) is an important dicotyledonous medicinal plant as it is the sole source of vincristine and vinblastine that are used against a variety of cancers. Quantitative estimation of vincristine was carried out using high performance liquid chromatography (HPLC) in various in vitro grown tissues; calluses (embryogenic and non-embryogenic callus), embryogenic stages (proliferated, matured and germinated embryos), somatic embryo derived plantlets (leaf, root and whole plant) and leaves of ex vitro developed plantlets. The yield in those in vitro and ex vitro-developed tissues was monitored for 30 weeks. Except at an early lag period, vincristine production was detected up to 20–25 weeks old plant samples. Vincristine content was very high in leaf callus and germinated embryos. Leaves of in vitro raised plants showed higher amount of vincristine when compared to ex vitro-developed leaves of similar age. Vincristine production was tissue specific and age dependent that was discussed in detail in this present communication.     

Affordable and reliable plant sap-mediated template preparation for the detection of various phytopathogens by PCR assay

Plant pathogens like ‘Ca. Liberibacter’, phytoplasma, viruses and viroids cause diseases to almost all economically important plants. A simple and fast sap-mediated polymerase chain reaction (PCR) method for the detection of these pathogens infecting various plant hosts is described in the present study. Sap from selected plants was drawn aseptically on parafilm, from the mid-rib of young leaves. Depending on the type of host plant, sap was diluted to optimal concentration before PCR analysis. ‘Ca. Liberibacter’, Citrus tristeza virus (CTV) and Citrus exocortis viroid (CEVd) infecting citrus, and ‘Ca. Phytoplasma’ infecting pepper and sandal trees were tested by sap-mediated PCR. The reliability of this procedure was evaluated by comparing the findings with previously described protocols. The sap-mediated nucleic acid template preparation for PCR assay is devoid of laborious nucleic acid extraction and expensive chemicals. Hence the present method is rapid, economical and so can be employed for diagnosis of large number of plant samples.     

Local pricing system of forest products and its relations to equitable benefit sharing and livelihood improvement in the lowland community forestry program in Nepal

The study examines the relationships between local pricing system of forest products and its effects on equitable benefit sharing and livelihood improvement of user households who are living in and around the forests. The community forest user groups of lowland in Nepal have practiced low pricing strategy for high value forest products considering the access of socio-economically poor households. However, the study suggests that even though the low pricing strategy was designed considering poor households, rich households greatly benefited from the forest benefits. The study further enlightens that the low price for high value forest products particularly timber is counterproductive for equitable benefit sharing among the user households in the areas of heterogeneous socio-economic conditions. In addition, the strategy is defective for collecting adequate community fund and carrying out enough livelihood improvement activities at the local level.     

RESPONSE OF WHEAT TO INOCULATION WITH MYCORRHIZAE ALONE AND COMBINED WITH SELECTED RHIZOBACTERIA INCLUDING FLAVOBACTERIUM SP. AS A POTENTIAL BIOINOCULANT

A pot experiment was conducted to evaluate different arbuscular mycorrhiza sps. (AM) for their effect on plant growth, yield and nutrient uptake by wheat. All the AM fungal sps. significantly enhanced all the plant parameters and nutrient uptake by the plant. A positive correlation was observed between percent root colonization by AM fungi and most of the plant parameters studied. Glomus macrocarpum giving best results was selected for studying interactive effect with Azotobacter, Azospirillum (well-known PGPRs), and Flavobacterium and Proteus vulgaris (less studied PGPRs). All the PGPRs significantly increased most of the plant parameters studied and their combination with AMF had a synergistic effect. Amongst PGPRs, Flavobacterium gave best response both singly and in combination with AMF and thus, is a potential new bioinoculant for wheat. Application of 120 kg nitrogen (N) ha^?1was the best treatment. Inoculation with most of the PGPRs gave better response than 60 kg N ha^?1.     

Evaluation of efficiency of hemi-nested PCR assay for the detection of ‘Candidatus Liberibacter’ infecting citrus

Journal of Plant Diseases and Protection - The present study reports the development and evaluation of a hemi-nested polymerase chain reaction (hnPCR) assay for the efficient detection of...