Seed Quality, Chlorophyll and Carotene Content in Brassica Juncea L. Leaves at Two Growth Stages in Response to Rhizospheric Bacteria

Surya Prakash Dube, Riddha Dey, Seema Devi and Richa Raghuwanshi^*

Department of Botany, Mahila Mahavidyalaya, Banaras Hindu University, Uttar Pradesh, India.

Corresponding Author E-mail:richabhu@yahoo.co.in

DOI : http://dx.doi.org/10.12944/CARJ.12.2.25

Abstract:

Leaf pigments play a crucial role in photosynthesis and protection, which drives plant growth. Rhizospheric bacteria playing a pivotal role in promoting plant development, also affects leaf pigmentation. The present study was therefore aimed to assess the influence of plant growth-promoting rhizobacterial (PGPR) treatments on leaf pigments and plant growth at early stages in Brassica juncea (L.). Pot experiments were conducted with selected rhizobacteria for 2 months. Although plant responses varied among the different PGPR inoculants, Pseudomonas azotoformans (JRBHU5) and Pseudomonas gessardii RRBHU-1 (P21) exhibited, notable improvements in germination percentage, seedling vigor index, biomass and leaf variables viz. relative water content (RWC), live fine fuel moisture (LFFM), leaf pigment ratio and leaf dry matter content (LDMC). The pigments found in leaves (β and α carotene, and chlorophyll a and b) of mustard got remarkably increased in JRBHU5 and P21 treatments, analyzed through absorption spectrum analysis. The absorption spectrum of Brassica leaf extracts revealed red-shifts in absorption peak influenced by solvent polarity and growth stages. Fluorescence studies indicated enhanced leaf pigment fluorescence under UV light in JRBHU5, JRBHU6, P21, and JRBHU1 treated plants suggesting an efficient chlorophyll synthesis in the treated plants. PGPR inoculation maintained photosynthetic efficiency, promoting growth and delaying senescence.

Keywords:

Absorption spectra; Brassica juncea; Biopriming; Leaf pigments; PGPR; Vigour index

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