MATERNAL PHENOTYPIC EFFECTS DUE TO SOIL NUTRIENT LEVELS AND SINK REMOVAL IN ARABIDOPSIS-THALIANA (BRASSICACEAE)

Three levels of soil nutrients and systematic removal of racemes and s iliques, intended to reduce reproductive sink size, induced maternal e ffects in a genetically uniform, inbred accession of drabidopsis thali ana ecotype Col-0. Soil nutrient levels but not trimming treatments ca used significant differences in maternal plant weight and number of se eds per silique. Trimming and increased soil nutrient level resulted i n larger seeds. Germination rates were significantly affected only by the trimming main effect, while there were no significant effects on g ermination percentage. At 14 and 19 d harvest dates, soil nutrient lev el treatments resulted in significant differences in offspring aerial biomass, but this effect was nonsignificant at 24, 29, and 34 d harves t dates. The effect of trimming on offspring aerial biomass was signif icant at all harvest dates. No significant soil nutrient level x trimm ing interaction was observed on any harvest date. Phenotypic correlati ons among aerial biomass at each harvest date and seed weight of the s ix offspring classes were highly significant. Analyses of variance for germination and biomass data adjusted for seed weight showed no signi ficant differences due to soil nutrient level, trimming, or their inte raction, indicating that maternal effects influencing these variables were determined by seed weight. Relative growth rates were estimated f rom changes in biomass over time. The negative correlation between ini tial relative growth rate and rate of change of the relative growth ra te was highly significant (R = -0.99; P < 0.01).