Parental Effects in Plantago Lanceolata L. Iii. Measuring Parental Temperature Effects in the Field

Abstract

Abstract. To determine the evolutionary importance of parental environmental effects in natural populations, we must begin to measure the magnitude of these effects in the field. For this reason, we conducted a combined growth chamber-field experiment to measure parental temperature effects in Plantago lanceolata. We grew in the field offspring of controlled crosses of chamber-grown parents subjected to six temperature treatments. Each treatment was characterized by a unique combination of maternal prezygotic (prior to fertilization), paternal prezygotic, and postzygotic (during fertilization and seed set) temperatures. Offspring were followed for three years to measure the effects of treatment on several life-history traits and population growth rate, our estimate of fitness.Parental treatment influenced germination, growth, and reproduction of newborns, but not survival or reproduction of offspring at least one year old. High postzygotic temperature significantly increased germination and leaf area at 17 weeks by approximately 35% and 2%, respectively. Probability of flowering and spike production in the newborn age class showed significant parental genotype ϫ parental treatment interactions. High postzygotic temperature increased offspring fitness by approximately 50%. The strongest contributors to fitness were germination and probability of flowering and spike production of newborns. A comparison of our data with previously collected data for chambergrown offspring shows that the influence of parental environment on offspring phenotype is weaker but still biologically meaningful in the field.The results provide evidence that parental environment influences offspring fitness in natural populations of P. lanceolata and does so by affecting the life-history traits most strongly contributing to fitness. The data suggest that from the perspective of offspring fitness, natural selection favors parents that flower later in the flowering season in the North Carolina Piedmont when it is warmer. Genotypic-specific differences in response of offspring reproductive traits to parental environment suggest that parental environmental effects can influence the rate of evolutionary change in P. lanceolata.

Natural selection contributes to geographic patterns of thermal plasticity in Plantago lanceolata

“…Parental temperature effects were largely reduced by controlling the postzygotic temperature during flower development and seed maturation (Case, Lacey, & Hopkins, 1996;Lacey & Herr, 2000).…”

“…When growing conditions are warm (e.g., 27°C day/20°C night), nearly all individuals produce spikes that are lightly colored and highly reflective (as in D). As the color of spikes lighten from left to right (a-d), the percentage of light reflected at 850 nm (i.e., floral reflectance) increases 1996; Lacey & Herr, 2000). At this point, no cost of this type of plasticity has been detected in terms of reproductive output (Lacey et al, 2012).…”

Transgenerational plasticity in clonal plants

“…Herbivory on Raphanus raphanistrum maternal plants influences the defensive systems of their offspring (Agrawal 2002). Temperature of the maternal environment can affect the germination, growth and reproduction of progeny of Plantago lanceolata (Lacey and Herr 2000). Different aspects of the maternal environment can have interactive effects on progeny performance, as is the case in Plantago for disturbance regimes and nutrient levels (Latzel et al , 2010.…”

Effect of photoperiod during growth of Chenopodium rubrum mother plants on properties of offspring

“…However, 100 % offspring of mother plants grown 6 d under 8-h photoperiod + 9 weeks 16-h photoperiod flowered. Maternal environmental effects on offspring flowering was also noticed in Plantago major (maternal soil nutrient effect) and persisted for three generations (Miao et al 1991), and in Plantago lanceolata (maternal effect of high temperatures) (Lacey and Herr 2000).…”