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Section XIV : Plant Sciences 165
microorganisms have proved to be better alternative for the large scale production
of L-asparaginase as they can be cultured easily and the extraction of enzyme is
also easy. L-asparaginase obtained from bacterial culture Erwinia carotovora
MTCC 1428 is an intracellular enzyme, hence cell disruption is mandatory to
release the enzyme for further purification. It was required to select a method of
cell lysis which causes least loss in enzyme activity with maximum recovery. Cells
of E. carotovora were lysed by different physical (vortex, motor and pestle,
sonicator, bead beater), chemical (alkali lysis, acetone powder, guanidine-HCl and
triton X-100) and enzymatic (lysozyme) methods. It was found that out of all
methods tested, enzyme release was found to be the best when cells were disrupted
by sonication. Specific activity of enzyme was found to be 1. 19 U/mg which was
the maximum among all the methods tried, the loss was also minimum(25%) in this
case.
207. Nitric Oxide Modulates Specific Steps of Auxin-induced Adventitious
Rooting in Sunflower
Sunita Yadav* and Satish C. Bhatla
Laboratory of Plant Physiology and Biochemistry;
Department of Botany; University of Delhi;
North Campus; Delhi-110007
Keywords : Adventitious roots, nitric oxide, auxin, sunflower
Auxin-mediated adventitious root (AR) formation from the basal ends of
hypocotyls segments in Sunflower (Helianthus annuus L. cv. Morden) exhibits
nitric oxide (NO)-dependent and NO-independent roles of auxin in this developmental
process. Root induction phase is evident within 1d (24 h) in the
interfascicular parenchyma while NO accumulation in the interfascicular cells 2
d after indole-3-acetic acid (IAA) treatment highlights the involvement of NO
during root initiation phase. Thus, adventitious root induction is strictly auxindependent
though initiation and extension phases involve an interaction of auxin
and NO. Treatment of hypocotyl explants with 10 µM 1-napthylphthlamic acid
(NPA), an inhibitor of polar auxin transport, lead to suppression of adventitious
roots and a complete abolition of NO-associated fluorescence. Use of an actin