IN VITRO AND IN VIVO MOISTURE STRESS TOLERANCE IN SUNFLOWER (Helianthus annuus L.)
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Date
2005
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ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD
Abstract
An investigation was carried out with six sunflower genotypes viz.,
SF 02, BRISF 23, BRISF 73, DSI 26, KBSH 1 and Morden with the main
objective of screening the genotypes for moisture stress tolerance under in
vitro and in vivo. Studies were also conducted to determine the effect of
different hormonal combinations and concentrations on callus induction and
shoot formation of the explants (embryo and shoot tip).
Tissue culture studies indicated that embryos cultured on MS + 1 mg
l-1 IAA + 0.5 mg l-1 BA higher callus initiation while, maximum multiple
shoot induction was obtained on MS basal + 0.1 mg l-1 NAA + 1 mg l-1 BA.
Multiple shooting from shoot tip was maximum on MS basal + 0.5
mg l-1 BA.
Data were recorded for various characters, one month old seedlings
both under in vitro and in vivo conditions. The seedling characters exhibited
greater variation with the imposition of stress under in vitro (-0.3 MPa –0.6
MPa and –0.9 MPa) and in vivo (25%, 50% and 75% stress level). The shoot
length, number of leaves per plant, shoot growth and root growth (in terms
of fresh weight and dry weight) were observed to decreased progressively as
the stress level increased under in vitro (-0.3 MPa to -0.9 MPa) and in vivo
(25% stress to 75% stress).
The shoot growth was found to be more affected than the root growth
under water stress. The root / shoot ratio in terms of fresh weight and dry
weight increased with increasing levels of stress under in vitro and in vivo,
with highest root/shoot ratio at –0.9 MPa and 75% stress levels. Among
morphological parameters studied, shoot fresh weight recorded maximum
reduction followed by shoot length both under in vitro and in vivo.
The proline and reducing sugar content reached maximum at 75%
stress level (in vivo) in the leaf tissue. SPAD chlorophyll content,
chlorophyll stability index percentage, leaf water potential and transpiration
rate decreased with increasing stress level when compared to control.
Among the six sunflower genotypes tested, BRISF 73 recorded
minimum reduction for shoot length, shoot fresh weight, shoot dry eight,
root fresh weight and root dry weight and BRISF 23 recorded more number
of leaves per plant even at higher stress levels of PEG induced water stress.
Under in vivo, BRISF 73 recorded minimum reduction for plant height,
shoot fresh weight, shoot dry weight, where as number of leaves, root fresh
weight and root dry weight recorded minimum reduction in the genotype
BRISF 23 even at higher stress levels from control.
The inter relationship among morphological characters of the
seedlings revealed significant positive correlation between in vitro and
in vivo studies for various characters. SDS PAGE analysis of total proteins
will provide additional support to the findings of in vitro and in vivo at
molecular level. In vitro and in vivo studies indicated that an in vitro
approach could be useful in screening and selection of sunflower genotypes
for their response to water stress prior to field trial. In vitro characters could
provide clues for pot or field performance of sunflower genotypes grown
under water stress conditions.
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Keywords
IN VITRO, IN VIVO, MOISTURE, STRESS, TOLERANCE, SUNFLOWER