Lok Man S. Palni

Clonal variation in temperature response of photosynthesis in tea

Abstract The effect of temperature on the photosynthetic characteristics of six tea clones (viz., 6017, B/5/63, B/6/61, B/6/62, CCS-26 and T-78), originally from different agro-climatic zones in India, was studied to determine the clonal variation in photosynthesis, if any. The results clearly indicated significant clonal differences in relation to temperature. Of the six clones, B/5/63 and B/6/61 were found to be relatively thermotolerant. Both stomatal and mesophyll components seemed to be responsible for the differences in temperature dependence of photosynthesis, however, their magnitude varied with the tea clones. Differences in water use efficiency were also observed between clones. However, differences became less pronounced at the higher temperature. Clone B/5/63 showed higher water use efficiency and lower values for stomatal conductance and transpiration. Thus this clone may be suitable for relatively dry and exposed sites. A 2–10-fold increase in dark respiration with increase in temperature was also observed. However, higher increase was associated with clones having higher photosynthetic rates, indicating an association between photosynthetic and respiratory rates. The results provide a valuable indication regarding clonal variation in temperature responses of photosynthesis and may be used to offer useful suggestions to tea growers in the initial selection of tea clones.

Selection of Elites and In Vitro Propagation of Selected High-Value Himalayan Medicinal Herbs for Sustainable Utilization and Conservation

Reduction in the forest cover from the Indian Himalayan region (IHR), due to overexploitation, has resulted in decreased availability of non-timber forest products, including medicinal plants of high economic value. With the ever-increasing human population and growing demand for plants and plant-derived products, there has been tremendous anthropogenic pressure on these primary producers. Many plant species are a source of high-value drugs; due to increasing global demand for the ‘naturals’, they are being subjected to reckless, often illegal harvesting, well beyond the natural regeneration capacity. This has led to many species being listed in the Red Data Book or in various IUCN threat categories. Improper harvesting (season and/or age of the plant/plant parts) not only results in uneconomical yields due to low content of active ingredients but also adversely affects the process of natural regeneration. There is, therefore, an urgent need for commercially important species to be subjected to improved management practices and regulated harvesting to generate better economic benefits on one hand and to encourage cultivation for sustained utilization as well as economic development of the region on the other. This twin strategy would also help to improve the conservation status of such species.

Alterations in growth, photosynthetic activity and tissue-water relations of tea clones in response to different soil moisture content

Key messageSignificant effect of water stress conditions were observed on morphological and physiological growth parameters of tea (Camellia sinensis). Water stress tolerant tea clones suitable for hilly areas have been identified in this study.AbstractThe influence of different levels of water deficit on physiological and morphological parameters in tea [Camellia sinensis (L.) O. Kuntze] clones was investigated. Tea clones (BSS-449, BSS-379, P-312, UPASI-9, T-383, RR-17, AV-2 and T-78) growing under controlled condition (under shade, potted condition) were subjected to three irrigation treatment, a control (70.0% soil moisture content), moderate water deficit (38.3% soil moisture content) and sever water deficit (6.9% soil moisture content). Plants submitted to severe water deficit showed significant reduced leaf numbers, leaf areas, and plant heights while reduction in plant height and leaf area and leaf numbers was not significant in moderate water deficit. A significant change in chlorophyll content was observed during the water stress condition. Photosynthesis decreased in both water deficit treatments and was related to stomatal factors and photochemical efficiency of photosystem II. Water relation parameters, e.g. leaf water potential, osmotic potential, turgor potential, relative water content and cellular elasticity were also measured to evaluate plant adaptation to water stress. The highest leaf water potential values were found in the control condition, for all the clones. Cell wall rigidity, measured as elastic modulus, increased under severe water stress, resulting in a loss of turgor at lower leaf water potential. Results of the study suggest that the degree of drought tolerance depends on the interactions between the tea clones and the levels of water stress. The available data also indicates that UPASI-9 is capable of tolerating water stress, and should be suitable for dry areas.

Variations in the Seasonal Snow Cover Area (SCA) for Upper Bhagirathi Basin, India

Satellite based remote sensing is a convenient tool for the study of cryosphere that allows to carry out investigations over large and inaccessible areas. The present investigation has been carried out to monitor seasonal variation in the Snow Cover Area (SCA) for the upper Bhangirathi basin, located in the Garhwal region of Indian Himalaya . This analysis has been done using Moderate-Resolution Imaging Spectroradiometer (MODIS) satellite data for the past 11 years (2000–2010); the temporal snow cover being derived using the Normalized Difference Snow Index (NDSI ). The entire study basin has been divided into nine elevation zones, on the basis of Digital Elevation Model (DEM), for estimating the SCA for each zone. Zones 1–9 cover different elevation ranges: (1) above 6,500 m, (2) between 6,000 and 6500 m, (3) 5,500–6000 m, (4) 5,000–5500 m, (5) 4,500–5000 m, (6) 4,000–4500 m, (7) 3,500–4000 m, (8) 3,000–3500 m, and (9) below 3,000 m. Mann Kendall and linear regression methods have been employed to identify trends in the SCA during the period 2000–2010. The snow cover depletion analysis depicts a shift in the duration of ablation and accumulation during the study period in the basin. The analysis indicated 13–21 % increase in SCA in the middle elevation zones (4 and 5) and 2–9 % decline in SCA in the lower elevation zones during autumn. SCA was found to increase across all the elevation zones in winter; the rate of increase was particularly high (14–21 %) in the lower elevation zones as compared to higher (2–3 %) and middle elevation zones (4–10 %). Similarly, an increase of 2–3 % in the higher elevation zones, 6–14 % increase in the middle elevation zones and 2–6 % decline in the lower elevation zones was observed in respect of SCA during spring. However, no significant variation in SCA was observed during the summer season. Decadal variation in SCA showed mean annual increase of 8–15 % in the middle elevation zones (3–5). In the lower elevation zones (<4,500 m), mean annual SCA showed increase of 11–14 % between 2000 and 2005, followed by 6–8 % decrease in the upper Bhagirathi Basin.

Conservation of Himalayan bioresources: An ecological, economical and evolutionary perspective

The Himalayan ranges are the youngest and loftiest among the mountain systems of the world. They represent a highly complex and diversified system both in terms of biological and physical attributes. Their vulnerability toward natural and human-induced disturbances is well recognized. On account of richness and uniqueness of biodiversity elements, the region has been recognized as one of the 34 global biodiversity hotspots. It represents 3 sub-centers (west Himalaya, east Himalaya and north east region) of plant origin, which, respectively, contribute 125, 82 and 132 species of wild relatives. The eastern Himalaya and north eastern sub-centers are known for contribution to Musa and Citrus diversity. The prevailing primitive agricultural systems in the region and conscious and unconscious selections by indigenous farming communities have contributed toward enormous enrichment of genetic diversity in the form of land races. Diversity of representative natural ecosystems (grasslands and woodlands) and richness of endemic bioresources have added to the ecological significance of the Himalaya. Particularly, the alpine grasslands and the forests of the region exhibit unique features. Furthermore, medicinal and wild edible plants add substantially to the ecological and economic value of the region. However, Himalayan ecosystems and their components are highly vulnerable both due to geological reasons and on account of stress caused by increased pressure of population. Also, there are growing indications that the ill effects of these factors may be exacerbated on account of the impact of climate change. This would affect the very sustenance of the indigenous communities living in the uplands as well as downstream areas. Therefore, there is an urgent need for making conscious efforts for conserving all representative systems. In this context, the existing conservation area network in the region, which appears to be stronger than the country average, is one welcome initiative. This network, however, requires strengthening to provide adequate coverage to all representative ecosystems, particularly in north east. Need for a major shift in the conservation approach through community support, and by way of promotion of sustainable use concept, has been suggested to ensure conservation of Himalayan bioresources. This is pivotal for maintaining vital stocks of unique, often endemic elements, for the natural evolutionary processes to continue.