Both types of adjustments presumably accommodate more chloroplasts per leaf area contributing to photosynthesis. phoeniceum vs a greater number of mesophyll cells per leaf area in M. Furthermore, while acclimation to low temperature involved greater leaf mass per area in both species, this resulted from greater leaf thickness in V. This upregulation of morphological and anatomical features at lower growth temperature likely contributes to the success of both the species during the winter. While the symplastically loading biennial exhibited adjustments in the size of minor leaf vein cells (consistent with adjustment of the level of sugar‐synthesizing enzymes), the putative apoplastic biennial exhibited adjustments in the number of cells (consistent with adjustment of cell membrane area for transporter placement). In both species, acclimation to lower temperature involved greater maximal photosynthesis rates and vein density per leaf area in close correlation with modification of minor vein cellular features.
Demmig‐Adams, Barbara Adams, William W.Īcclimation of leaf features to growth temperature was investigated in two biennials (whose life cycle spans summer and winter seasons) using different mechanisms of sugar loading into exporting conduits, Verbascum phoeniceum (employs sugar‐synthesizing enzymes driving symplastic loading through plasmodesmatal wall pores of phloem cells) and Malva neglecta (likely apoplastic loader transporting sugar via membrane transport proteins of phloem cells). Leaf architectural, vascular and photosynthetic acclimation to temperature in two biennials Leaf architectural, vascular and photosynthetic acclimation to temperature in two biennials