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EFFECT OF EXOGENOUS SUPPLY OF BORON ON NODULE DEVELOPMENT IN PEA (PISUM SATIVUM L.)

FERHAT MEHMOOD¹, MUHAMMAD QASIM^2*, ZAHEER UD DIN KHAN¹ AND SYED HAMMAD RAZA²

Abstract: Exogenous supply of boron was evaluated on the seeds of Pisum sativum L. inoculated with Rhizobium leguminosarum and grown in aqua-culture. The liquid nutrition medium contained six boron concentrations (control, 1, 1.86, 2.86, 3.86, and 4.86 mg L^-1). The results obtained from the present work showed that number of nodules, size of nodules and weight of nodules exhibit great improvement in 2.86 mg L^-1 boron treatment. Toxic effect of high concentration of boron (4.86 mg L^-1) was also recorded. There was significant reduction as compare to control in nodule weight, size and numbers. This fact becomes clear while observing the nodules growing in the boron free culture, which did not develop extensively. The comparison of the transverse sections of root-nodule area, from nutrient solutions with various boron concentrations showed that in the absence of boron, there was a considerable hypertrophy in cambial cells and a frequent disintegration of phloem and ground tissue along with xylem. The disintegration of the tissue seems to be linked with nodule bacteria. The nodular bacteria are considered to assume a parasitic habit in the absence of boron.
 

¹Department of Botany, GC University Lahore, Pakistan
²Department of Botany, GC University Faisalabad, Pakistan