ObjectivePlant resource allocation is limited such that an increase reproduction incurs a reduction in other functions, quantified as reduced current growth, development or survival. This phenomenon is called reproductive cost based on the theory of life history evolution. Sometimes the cost of reproduction can be shown in the trade-off between the cost of reproduction in the current year and the growth in the future, suggesting that the reproductive cost has a delayed effect. Dioecious plant Acer barbinerve, in which reproductive functions are separated into two distinct sexual forms, is especially suitable for studying the delayed effect of reproductive cost in a coniferous and broadleaved mixed forest in Jiaohe, Jilin Province of northeastern China.
MethodTo explore the delayed effect of reproductive cost, we selected 90 female and 90 male individuals with no significant difference in size of dioecious species Acer barbinerve in 2012. The individuals of each sex were divided into three treatments (A, control; B, removing flower called flowers only without fruits; C, removing flower bud). We investigated the reproduction and growth of Acer barbinerve in different treatments in 2013 and 2017. Two-way ANOVAs was performed to test the difference of length of new shoot and foliage biomass for each sex under different treatments.
ResultIn flowering time in 2013, the sequence of length of new shoot was group C > group B > group A at shoot and branch level, in which the difference of group B and group C with group A was significantly separated. The differences under different treatments of male were significant. In flowering times in 2013, the foliage biomass of female was group C > group B > group A at shoot and branch level. The leaf biomass of male plants in the flowering times at shoot level of 2017 was C > B > A, in which group C was significantly larger than group A.
ConclusionThe delayed effect of reproductive cost of dioecy Acer barbinerve was influenced by module level and showed sexual difference in different vegetative organs and nutrient distribution, also had gender differences in the duration.