Response in germination and
seedling growth in Phaseolus mungo
under salt and
drought stress
Gunjan Garg*
School of Biotechnology, Gautam Buddha
University, Gautam Buddha Nagar,
Greater Noida (NCR) - 201 308, India
(Received: October 21, 2008; Revised
received: February
17, 2009; Accepted: March 02, 2009)
Abstract: The effect of salt and drought stress
at the water potentials of -2, -4,-6 and -8 bars induced by NaCl
and PEG 6000 (Polyethylene glycol
6000) each, on germination and early seedling growth, were investigated for two
varieties (PU-19 and Type-9). Electrical conductivity (EC) value of the NaCl solutions were 4.5, 8.8, 12.7 and 16.3 dS m-1. Germination percentage, root and shoot length, and
seedling fresh and dry weight were measured in the study. The objective was to
determine genotypic differences among P.mungo
varieties in terms of salt and drought stress and to determine factors(salt toxicity or osmotic stress due to PEG) inhibiting seed germination. The germination
results revealed that the genotypes significantly differed for salt and drought
stress. PU-19 appeared to be more tolerant to salt and drought stress
comparable to var. Type-9. Both NaCl and PEG inhibited germination and seedling growth in both
the varieties, but the effects of NaCl compared to PEG was less on germination and seedling growth. All
varieties were able to germinate at all NaCl levels
without significant decrease in germination, while a drastic decrease in
germination was recorded at -6 and -8 bars of PEG.
It was concluded that inhibition in germination at equivalent water potential
of NaCl and PEG
was mainly due to an osmotic effect rather than salt toxicity.
Key words: Salt toxicity, Osmotic stress, Seed germination,
Seedling growth
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