ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 86 Number 4
Changes in growth, cell division and metabolism of sugarcane in response to nickel. (128)
Effect of graded concentrations of nickel (as Nickel chloride 1, 5, 10, 50 and 100 ppm) was studied on growth, cytological and biochemical parameters and nutrient uptake of sugarcane (Saccharum sp. hybrid CoLk 8102) planted under field conditions. At very low levels of Ni (1 and 5 ppm Ni), there was marked improvement in root number, leaf length , width, area and settling height, whereas, at high Ni (50 and 100 ppm) levels, these attributes decreased significantly. Root growth was affected more severely than shoot growth due to high Ni supply (50 and 100 ppm Ni). At lower levels of Ni, mitotic index showed an improvement of 5.46 %, but it declined to 65.32% at 100ppm Ni. Plants supplied with graded concentrations of Ni exhibited variation in chlorophyll a, b and total, and Hill reaction activity. Chlorophyll a ranged between 2.00 to 2.32, chlorophyll b from 0.60 to 0.78 mg per g fresh weight and Hill reaction activity from 3.70 to 6.76 delta OD per mg fresh wt per h. The micronutrient contents viz., Fe, Mn, Zn and Cu decreased in leaves and stalk at 50 and 100 ppm Ni compared to control. While in roots, the reverse was true with almost all the elements decreased except Cu. Ni concentration in leaves and roots increased with an increase in Ni supply; in roots it was higher than that of leaves. Yield attributes viz., stalk height, girth and cane weight did not show any remarkable difference. However, number of millable canes showed improvement of 7- 29 % at lower levels and at high levels NMC decreased by 40 % over control. Brix value of millable canes at early stage of ripening (in the month of September) was 16.0 at lower level (5 ppm Ni) and 14.2 to 14.0 at higher levels ( 50 and 100 ppm Ni ) of Ni as compared to control (15.2). However, at maturity, sucrose % cane juice did not show much difference. Results obtained indicated beneficial effects of Ni at lower levels (1 and 5 ppm Ni) on sugarcane growth, mitotic efficiency and yield attributes, while high levels (50, 100 ppm Ni) exhibited inhibitory effects on shoot and root growth, metabolic attributes and nutrient uptake and was found to be cytotoxic.
Keywords: Nickel, cell division, chlorophyll, Hill Reaction activity, yield attributes, sugarcane