~ 239 ~ ISSN Print: 2394-7500 ISSN Online: 2394-5869 Impact Factor: 5.2 IJAR 2016; 2(8): 239-242 www.allresearchjournal.com Received: 05-06-2016 Accepted: 06-07-2016 Ambika Beri Department of Botany, Govt. Mohindra College, Patiala, Punjab, India Rajeev Sharma Department of Chemistry, Multani Mal Modi College, Patiala, Punjab, India Ambika Beri Department of Botany, Govt. Mohindra College, Patiala, Punjab, India Nickel toxicity to photosynthetic attributes in the leaves of lentil (Lens culnaris Medic. Masar) Ambika Beri and Rajeev Sharma Abstract Nickel is an essential micronutrient for plant growth but beyond optimum limits it becomes highly toxic. The excess concentration of nickel in the soil deleteriously effect the plant metabolism particularly photosynthesis. Lentil (Lens culinaris Medic.) is an important legume crop. The objective of this study was to investigate the effects of nickel on main photosynthetic pigment, Hill activity and activity of key enzyme of photosynthesis i.e. Rubisco. Along with this changes in the morphological parameter related with this process were also taken into consideration i.e. number and size of stomata. In the sand culture experiment lentil plants were analyzed on the 30th day after sowing in the sand amended with various levels of Nickel (1mM, 4mM, and 6mM). Nickel at all levels tested decreased the number and size of stomata in the leaves, chlorophyll a, chlorophyll b and total chlorophyll content, Hill activity and Rubisco activity as compared to control plants. Keywords: Lentil, Lens culinaris, cadmium, nickel, hill activity, Rubisco, stomata Introduction The amount of heavy metals in the environment is increasing continuously as a consequence of the increased environmental pollution from industrial, agricultural and municipal sources (Adrino, 1986) [1] . Nickel is one such ubiquitous transition metal which is emitted into environment from both natural and anthropogenic sources (WHO 1991). The concentration of nickel is increasing in soils by human activities such as mining works, emission of smelters, burning of coal and oil, sewage, phosphate fertilizers, bad watering pratices in agricultural land and excessive and non judicious use of pesticides (Gimeno-Gracia et al. 1996; Bell et al., 2001, Parsariello et al., 2002) [14, 5, 21] . Although Nickel is a heavy metal, but it is one of the essential microelement for plants, animals and humans, but toxic at higher concentrations exceeding optimum intake values. Beyond its (Seregin and Kozhevenikova, 2006; Chan et al. 2009) [23, 8] permissible limits Ni 2+ in soils causes various physiological alterations and toxicity symptoms like chlorosis and necrosis in different plant species (Pandey and Sharma 2002; Madhava Rao and Sresty, 2000) [21, 20] . Heavy metals are known to cause non-specific inhibition of photosynthesis by several direct and indirect means. The slow rate of photosynthesis is related to disrupted chloroplast structure, inhibited activities of Calvin cycle enzymes and CO2 deficiency caused by stomatal closur e (Sergin and Ivanov 2001). Excessive Ni is known to inhibit seed germination, plant growth, mitotic activities (Madhava Rao and Sresty, 2000), [20] induce chlorophyll degradation, chlorosis, and interfere with photosystems I and II activity (Leon et al. 2005) [18] . The purpose of the present study is to contribute to a better understanding of biochemical and physiological responses of lentil (Lens culinaris Medic.) subjected to nickel stress. Our work focuses on the study of the effects of different concentrations of nickel on size and number of stomata, chlorophyll content, Hill activity and enzyme Rubisco in the leaves of Ni 2+ treated 30 days old Lentil plants grown in sand culture. Material and Method Seeds of lentil (Lens culinaris var. Masar 9-12) used for the present investigation were procurred from the market. International Journal of Applied Research 2016; 2(8): 239-242