ABSTRACT
Two genets of Abutilon theophrasti were clonally replicated and grown to maturity in a glasshouse at two levels of nutrient supply. The seeds produced were weighed and the resulting seedlings exposed to two nutrient levels during development. The progeny plants were harvested on three occasions, and leaf areas and dry weights of the different plant parts were determined. At the early stages of growth an increase in the maternal nutrient supply significantly increased seedling height, cotyledon area, and leaf areas, and seed weight had a significant effect on several traits. The maternal nutrient addition had no significant effect at a later stage of growth (35 d after sowing), but at 56 d after sowing it did affect offspring leaf areas and dry weights. Significant interaction terms indicate that the response to parental nutrient addition may depend both on genotype and on the nutrient status of the progeny. Different plant characters are differentially sensitive to maternal conditions and these may be expressed at different stages of development.
ABSTRACT
Four genotypes of P. lanceolata were grown to maturity at combinations of two levels of atmospheric CO2 concentrations and two temperature conditions. Seed weight was determined, and seed germination and seedling growth were measured for the progeny of each genotype under the same environmental conditions. Overall, high CO2 levels decreased seed weight, increased germination percentage and rate, and increased seedling size. Families differed in their response to CO2 enrichment, and to combinations of CO2 and temperature levels for several characters. These results suggest the existence of genetic variability in P. lanceolata in response to CO2 enrichment.
