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 lines^1/ 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.

�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.__