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Plant fitness is typically correlated with total seed biomass or the number of seeds produced per plant, but the connection from seed production to seedlings the following year is seldom made. Seedling production in grasses, including wild rice ( Zizania palustris L.) is determined by the number of inflorescences produced, the number of seeds per inflorescence, the mean mass per seed, proportion of seeds that are filled, predation on seeds, and germination rates. Previous studies have shown that wild rice biomass production is limited primarily by nitrogen and secondarily by phosphorus and light. To test how nitrogen, phosphorus, and light modulate plant fitness, we evaluated the effects of nitrogen, phosphorus, and light on the above parameters. Nitrogen addition increased number of inflorescences, seeds per inflorescence, and mean seed mass, resulting in more seedlings produced, hence greater fitness, despite increased rice worm predation and lower germination rates of seeds compared to seeds from plants grown without nitrogen addition. Phosphorus additions and full sunlight also increased the number of seedlings per plant, mainly after nitrogen was added. Therefore, the maternal environment not only affects seed production but the number of seedlings that emerge the following year, especially with respect to nitrogen. [ABSTRACT FROM AUTHOR]

Repetitive plant parts such as seeds can be characterized at the within-individual level not only by average values but also by higher moments of their distributions, such as the standard deviation, skewness, and kurtosis. These parameters can potentially be adaptive and shaped by selection like any other individual trait, but tend to be understudied. We present an example of how within-individual variation might be studied. We used a diallel crossing design to investigate the sources of phenotypic variance of among- and within-individual variation in seed and germination traits of the endemic columbine Aquilegia pyrenaica subsp. cazorlensis (Heywood) Galiano & Rivas Martínez. Individual plants and even fruits have their characteristic mean, standard deviation, skewness, and kurtosis and therefore these parameters could potentially respond to selection. However, we only found evidence of genetic variance in mean within-fruit seed mass, mean time to seedling emergence, and number of seeds: these effects were attributable to maternal effects. Variance in higher moments of the within-fruit distributions in this species could instead reflect developmental instability or plastic responses to localized environmental conditions as fruits develop. Large sample sizes are required to make final conclusions in this case, but this study illustrates how the novel approach of considering high moments of intra-individual variation will enhance our view of plant trait evolution. [ABSTRACT FROM AUTHOR]