CHARACTERIZATION OF A WILTY SUNFLOWER (HELIANTHUS-ANNUUS L) MUTANT .3. PHENOTYPIC INTERACTION IN RECIPROCAL GRAFTS FROM WILTY MUTANT AND WILD-TYPE PLANTS
M. Fambrini et al., CHARACTERIZATION OF A WILTY SUNFLOWER (HELIANTHUS-ANNUUS L) MUTANT .3. PHENOTYPIC INTERACTION IN RECIPROCAL GRAFTS FROM WILTY MUTANT AND WILD-TYPE PLANTS, Journal of Experimental Botany, 46(286), 1995, pp. 525-530
The present study was conducted to evaluate phenotypic interaction in
reciprocal grafts between wilty (w-1) sunflower mutant and normal (W-1
) plants. The w-1 genotype is a 'leaky' ABA-deficient mutant, characte
rized by high stomatal conductance, in both light and dark conditions,
and high transpiration rate, In well-watered conditions, mutant scion
s grafted on to normal rootstock (w-1/W-1) showed higher leaf relative
water content, leaf water potential and ABA levels than those of cont
rol grafts (w-1/w-1), in addition, detached leaves of w-1/W-1 exhibite
d lower water loss than w-1/w-1 grafts, while mutant rootstock did not
affect the transpiration rate of detached W-1 leaves. When drought st
ress was imposed to potted plants by withholding water, the mutant sci
ons grafted on to normal roots showed a partial phenotypic reversion.
A rapid stomatal closure and a rise in ABA levels in response to a sma
ll decrease in leaf water potential was observed. By contrast, in w-1/
w-1 grafts significant reductions in stomatal conductance and ABA accu
mulation were detected only in conjunction with a severe water deficit
, W-1 scions on mutant stocks (W-1/w-1) maintained the normal phenotyp
e of control wild-type grafts (W1/W-1),