Extravagant leaves display in Actinidia kolomikta attracting pollinators and maintaining photosynthetic capacity

Abstract

AbstractPollinators usually are attracted by flower displays, but whether non-green leaves display can function as a flower guide is less well studied. Furthermore, it is still largely unknown whether photosynthetic cost is paid-off by benefits afforded by attraction pollinators and how non-green leaves maintain photosynthetic capacity. Thus, white leaf and inflorescence/flower traits, pollinator visitation, fruit set and seed production, spectral properties, leaf structure, net photosynthetic rate and chlorophyll fluorescence of adaxial and abaxial surface were studied in Actinidia kolomikta (Rupr. & Maxim.) Maxim. The reproductive branches of A. kolomikta have a large number of white leaves at the exterior canopy, but white inflorescences grow at the canopy’s interior, and we found that showy display of white leaves attracted pollinators reach the flowers. Although incident light was reflected largely, we found that photosynthetic rate of white leaves was maintained at relatively high levels. Furtherly, spongy tissue play the vital role in maintenance photosynthetic capacity of white leaves, which effectively supports inflorescence development during flowering. Thus, white leaves of A. kolomikta enhanced reproductive fitness through attracting pollinators and decreasing reproductive cost: (1) spatially via white leaves locating at reproductive branches and temporally via synchronism between white leaves and flowers; (2) increasing white leaves display and decreasing investment in reproduction; (3) compensatory mechanisms via maintaining photosynthetic capacity of white leaves. Therefore, we propose that these dual functions of white leaves during blossom lower the plant’s cost of reproduction, and that this is an adaptation to the climatic challenges of the high altitudes and latitudes at which it grows.