4.3 Fitness optimization - an integral view of reproductive pattern
Reproductive pattern – how reproductive effort is allocated in different reproductive modes is directly correlated with the fitness of clonal plants (Wang et al., 2021b). The shift in reproductive pattern in different ecological conditions, as a representative of adaptive phenotypic plasticity, likely optimize the fitness of clonal plants in changing scenarios (Li et al., 2018).
In an integral view, the tested four populations from different geographic sources showed an adaptive plasticity in reproduction pattern under different warming conditions. First, population 1 and 3 showed a maintenance in asexual propagation especially the turion biomass production under different warming conditions, while the sexual reproduction was totally lost under warming. This shift in reproduction pattern seems a non-adaptive plastic response to warming. However, it is noteworthy that a higher percentage of pleiophyllous turions generated under warming. Since the scale leaf is correlated with the nutrient storage, photosynthetic capacity and the axillary bud number thus the sprouting potential, an increase in the percentage of pleiophyllous turions likely enhances the fitness and thus compensates the complete loss of sex (Xie & Yu, 2011; Qian et al., 2014; Adamec, 2018). Second, population 2 presented an increase in clonal propagation and simultaneously a decrease in sexual reproduction under warming. A prominent trade-off between asexual and sexual reproductive modes was shown in the shift of reproductive pattern (Herben et al., 2015). Although warming blocked the sexual reproduction and thus impeded the probable genetic variance in the progeny, the enhancement in the asexual propagule production is likely beneficial in maintaining the fitness. Lastly, population 4 also showed a coherent asexual propagation output under varied warming conditions. However, warming did not alter its sexual reproduction as no sex reproduction was manifested under both unwarming and warming conditions. As population 1 and 3, more pleiophyllous turions were recruited for population 4 under warming, and the fitness maximization might be realized. Overall, the fitness of the populations from four different geographic sources is predicted to be optimized under extreme warming.