On the contrasting morphological response to far-red at high and low photon fluxes

Frontiers in Plant Science

Plant Science

Bruce Bugbee¹  Paul Kusuma² 

[1] Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, UT, United States;Department of Plant Sciences, Horticulture and Product Physiology, Wageningen University and Research, Wageningen, Netherlands;Crop Physiology Laboratory, Department of Plants Soils and Climate, Utah State University, Logan, UT, United States;

关键词: far-red;    phytochrome;    shade avoidance;    shade tolerance;    photosynthetic photon flux density;    leaf expansion;   

DOI  :  10.3389/fpls.2023.1185622

 received in 2023-03-13, accepted in 2023-05-10,  发布年份 2023

来源: Frontiers

【 摘 要 】

Plants compete for sunlight and have evolved to perceive shade through both relative increases in the flux of far-red photons (FR; 700 to 750 nm) and decreases in the flux of all photons (intensity). These two signals interact to control stem elongation and leaf expansion. Although the interacting effects on stem elongation are well quantified, responses for leaf expansion are poorly characterized. Here we report a significant interaction between far-red fraction and total photon flux. Extended photosynthetic photon flux density (ePPFD; 400 to 750 nm) was maintained at three levels (50/100, 200 and 500 µmol m-2 s-1), each with a range of 2 to 33% FR. Increasing FR increased leaf expansion in three cultivars of lettuce at the highest ePPFD but decreased expansion at the lowest ePPFD. This interaction was attributed to differences in biomass partitioning between leaves and stems. Increased FR favored stem elongation and biomass partitioning to stems at low ePPFD and favored leaf expansion at high ePPFD. In cucumber, leaf expansion was increased with increasing percent FR under all ePPFD levels showing minimal interaction. The interactions (and lack thereof) have important implications for horticulture and warrant further study for plant ecology.

【 授权许可】

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