6
PNL Volume 17 1985
RESEARCH REPORTS
INFLUENCE OF st ON THE REMA1NINO PARTS OF LEAF
Cardi, T. and L. M. Monti
Plant Breeding Institute
University of Naples, Portici, Italy
Eight near-isogenic lines1/ from all eight possible combinations of
alleles at af, st, tl were grown along wire trellises in order to
evaluate actions and interactions of those genes. Plants were harvested
at the dry seed stage and oven-dry leaf weight was measured.
Besides the well known reduction in stipules themselves, the st
gene showed a pleiotropic effect on the weight of the remaining parts of
the leaf. In fact, the leaves (without stipules) of st st plants always
weighed less than St/St genotypes at the first flowering node.
However, differences were not the same in the four leaf phenotypes
(Table 1).
Because of heterogeneity of the error variances, statistical analy-
sis was performed separately for each phenotype. Only in afila plants
were there significant differences (P < 0.01); in other cases the stan-
dard error of the difference between the means was too large and/or the
difference between the means was too small to have statistical signifi-
cance. Our data do not allow us to specify which part of the leaf (i.e.
petioles, leaflets, or tendrils) is influenced by st.
The negative effect of st on yield and yield components we found in
our experiments (1) seems related not only with the reduction of stipule
size, but also with the weight (and, correspondingly, the area) of the
remaining part of the leaf. Negative effects of st are particularly
evident when it is associated with af in the "leafless" phenotype, in
which reduced growth rate and net CO2 uptake have already been shown (2,3).
1. Cardi, T. and L. Frusciante. 1984. Ann. Fac. Agraria, University
of Naples, Serie IV, XVIII:163-179.
2. Pyke, K. A. and C. L. Hedley. 1983. Ann. Bot. 52:719-724.
3. Snoad, B. 1981. Sci. Hort. 14:9-18.
2,
3.
Provided by G, A. Marx.
Table 1. Mean weight (mg) of leaf without stipules in the eight genotypes. Number of plants analyzed indicated in brackets.__
Leaf of phenotype
Leafed
(AfAfTLTl)
Afila
(afafTlTl)
Acacia
(AfAftltl)
Pleio
phila
afaf tltl
St St
192.6
(19)
198.1
(26)
251 0
(29)
560
(26)
st st
180. 3
(29)
123.6
(22)
216.1
(23)
445
(22)
**P < 0.01
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