Differential responses of photosynthetic parameters and its influence on carbohydrate metabolism in some contrasting rice (Oryza sativa L.) genotypes under arsenate stress.

Influence of arsenic (As) in As tolerant and sensitive rice genotypes based chloroplastic pigments, leaf gas exchange attributes and their influence on carbohydrate metabolism were investigated in the present study. As retards growth of crop plants and increase several health ailments by contaminating food chain. Photosynthetic inhibition is known to be the prime target of As toxicity due to over-production of ROS. Hydroponically grown rice seedlings of twelve cultivars were exposed to 25, 50, and 75 µM arsenate (AsV) that exerted negative impact on plastidial pigments content and resulted into inhibition of Hill activity. Internal CO2 concentration lowered gradually due to interference of As with stomatal conductance and transpiration rate that subsequently led to drop in net photosynthesis. Twelve contrasting rice genotypes responded differentially to As(V) stress. Present study evaluated As tolerant and sensitive rice cultivars with respect to As(V) imposed alterations in pigments content, photosynthetic attributes along with sugar metabolism. Starch contents, the principle carbohydrate storage declined differentially among As(V) stressed test cultivars, being more pronounced in cvs. Swarnadhan, Tulaipanji, Pusa basmati, Badshabhog, Tulsibhog and IR-20 compared to cvs. Bhutmuri, Kumargore, Binni, Vijaya, TN-1 and IR-64. Therefore, the six former cultivars tried to adapt defensive mechanisms by accumulating higher levels of reducing and non-reducing sugars to carry out basal metabolism to withstand As(V) induced alterations in photosynthesis. This study could help to screen As tolerant and sensitive rice genotypes based on their photosynthetic efficiency in As polluted agricultural fields to reduce As contamination assisted ecotoxicological risk.

Introducing winter rice cropping by using non-saline tidal water influx in western basins of South 24 Parganas, India.

A population exceeding 3.8 million people in the western region of 24-Parganas (South) is directly or indirectly reliant on agriculture as their primary source of livelihood. The agricultural trend shows a clear lack of multi-cropping with a drop of nearly 30% in rice cultivation during the winter season. Nearly 50% of the region is directly dependent on canals. The introduction of tidal water in the canal network provides an exceptionally economical and highly effective mode of irrigation water supply. The primary aim of the study was to identify the cartographic characteristics and channel hydraulics in the summer season. It was noted that the canals have a wide discharge range of 0.03-540.03 m3/s, average evaporation loss of 9.07 mm/day with a seepage loss ranging from 0.04 to 6.36 m3/s. The tidal water ingress quantity was calculated to be 4.17 Mm3, 5.32 Mm3, 1.88 Mm3 at Diamond Harbour sluice (Sl.), Kulpi Sl. and Kholakhali Sl. respectively. It was denoted that the augmentation of tidal backwater six times monthly would suffice the winter crop water requirement for the majority of the basins. This would result in the production of 172.13 kt which was previously 17.6 kt resulting in an increase of production by 878.01%. The per capita income would also be increased by nearly 978% for the season, resulting in the macro-socioeconomic upliftment of the region.

Modulation of photosynthetic parameters, sugar metabolism, polyamine and ion contents by silicon amendments in wheat (Triticum aestivum L.) seedlings exposed to arsenic.

The objective of the present investigation was to consider the effectiveness of exogenous silicate supplementation in reviving the arsenate imposed alterations on pigment content, Hill activity, photosynthetic parameters, sugar metabolism, polyamine, and ion contents in wheat (Triticum aestivum L. cv. PBW-343) seedlings. Experiments were conducted under different levels of arsenate (0, 25 µM, 50 µM, and 100 µM) in combination with silicate (0, 5 mM) in a hydroponic environment with modified Hoagland's solution for 21 days to determine the ameliorative role of silicon (Si). Arsenate exposure led to a decline in chlorophyll content by 28% and Hill activity by 30% on an average along with photosynthetic parameters. Activity of starch phosphorylase increased causing a subsequent decrease in starch contents by 26%. Degradation of starch enhanced sugar contents by 61% in the test cultivar. Dose-dependant increments in the activities of carbohydrate metabolizing enzymes viz., sucrose synthase, sucrose phosphate synthase, and acid invertase were also noted. Putrescine content was significantly enhanced along with a consequent decline in spermidine and spermine contents. The macro- and micronutrient contents declined proportionally with arsenate imposition. Conversely, silicate amendments irrespective of all arsenate concentrations brought about considerable alterations in all parameters tested with respect to arsenate treatment alone. Marked improvement in pigment content and Hill activity also improved the gas exchange parameters. Soluble sugar contents decreased and starch contents were enhanced. Increase in polyamine contents improved the ionic balance in the test cultivar as well. This study highlights the potentiality of silicon in ameliorating the ecotoxicological risks associated with arsenic pollution and the probable ability of silicon to offer an approach in mitigating arsenate-induced stress leading to restoration of growth and metabolism in wheat seedlings.

Inventorization of some ayurvedic plants and their ethnomedicinal use in Kakrajhore forest area of West Bengal.

ETHNOPHARMACOLOGICAL RELEVANCE: Medicinal Plant resources of forest origin are extensively used in India for various systems of medicine like Ayurveda, Unani, Homeopathy, Allopathy, Siddha and Ethnic etc. The tribal communities around the Kakrajhore forest in West Medinipur district of West Bengal have their own traditional knowledge based system of curing many diseases using the forest based plant resources similar to ayurveda. The forest comprises of one of the unique treasure and rich source of diversified ethno-botanical wealth and therefore extensive studies is required for proper documentation including ethnomedicinal knowledge of local tribes. AIM OF THE STUDY: The present study was initiated with an aim to inventorize the ayurvedic medicinal plant recourses and explore the traditional knowledge of tribal people of Kakrajhore forest to treat several diseases along with the sustainable management and conservation of medicinal plants. METHODS: The information on the medicinal plant resources were gathered through floristic inventorization with proper sampling method in the study area (N22°42'57.05″, E86°34'58.02″) during the year 2015. For floristic inventorization the study area of 312 ha was delineated by using GPS Receiver. Then total mapped area was divided by virtual grid of 100m apart in both East-West and North-South direction to allocate 60 sample plots by random sampling. In addition to inventorization, the use value (UV) of the species was determined and the informant consensus factor (ICF) was calculated for the medicinal plants found in the study area based on personal interview. Further exploration was carried out to establish linkage with Ayurveda. RESULTS: The present survey has identified 57 numbers of ethno-medicinal plants belonging to 39 families, used for preparing medicinal remedies. The habit of the plants includes 35% trees, 28% shrubs, 23% herbs and 14% climbers. The most frequently utilized plant parts were the Roots & Tuber roots (26%), Stem which includes Bark, Tubers, Bulb, Rhizome, Gum, Wood & Young shoots (24%), Leaves (18%), Fruits (13%), and Seeds (10%). The most frequent happening ailments are asthma and bronchitis, constipation and dyspepsia, diarrhea, dysentery, ulcer, rheumatism, arthritis, fistula and piles troubles. Most of the Plants (88%) had more than a single therapeutic use. The most important plant species on the basis of use value were Smilex ovalifolia, Emblica officinalis, Curculigo orchioides, Croton roxburghii, Asparagus racemosus, Ziziphus nummularia, Ichnocarpus frutescens, Cisssus adnata, Buettneria herbacea, Litsea glutinosa, Vernonia anthelmintica and Chlorophytum borivilianum. There was a strong agreement among the informants related to the usage of the plants (ICF 0.65-0.93). As per the standard literature in Ayurveda, maximum numbers of documented species (33) are found to be used for 'digestive system disorder' which is analogous to ethnomedicinal use (30), followed by 'skin related problem' i.e. 13 and 20 respectively. CONCLUSIONS: Results show that people living around Kakrajhore forest area hold valuable knowledge of the uses of plant resources and some of the ayurvedic plants represent an important component in local livelihood. Though the Kakrajhore Forest area is rich in medicinal plant resources but the species are susceptible to be endangered by intense exploitation by human communities. More in-depth investigations are required for plants with high UV values on their possible phytochemical and pharmacological activity. Apart from this, sustainable management approach and proper conservation strategy for the area is recommended by involvement of local communities and forest department.

Carbon sequestration rate and aboveground biomass carbon potential of three young species in lower Gangetic plain.

Carbon is sequestered by the plant photosynthesis and stored as biomass in different parts of the tree. Carbon sequestration rate has been measured for young species (6 years age) of Shorea robusta at Chadra forest in Paschim Medinipur district, Albizzia lebbek in Indian Botanic Garden in Howrah district and Artocarpus integrifolia at Banobitan within Kolkata in the lower Gangetic plain of West Bengal in India by Automated Vaisala Made Instrument GMP343 and aboveground biomass carbon has been analyzed by CHN analyzer. The specific objective of this paper is to measure carbon sequestration rate and aboveground biomass carbon potential of three young species of Shorea robusta, Albizzia lebbek and Artocarpus integrifolia. The carbon sequestration rate (mean) from the ambient air during winter season as obtained by Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 11.13 g/h, 14.86 g/h and 4.22g/h, respectively. The annual carbon sequestration rate from ambient air were estimated at 8.97 t C ha(-1) by Shorea robusta, 11.97 t C ha(-1) by Albizzia lebbek and 3.33 t C ha(-1) by Artocarpus integrifolia. The percentage of carbon content (except root) in the aboveground biomass of Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 47.45, 47.12 and 43.33, respectively. The total aboveground biomass carbon stock per hectare as estimated for Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 5.22 t C ha(-1) , 6.26 t C ha(-1) and 7.28 t C ha(-1), respectively in these forest stands.