Hydraulic Traits Emerge as Relevant Determinants of Growth Patterns in Wild Olive Genotypes Under Water Stress

Frontiers in Plant Science

Saray Gutiérrez-Gordillo¹  Jose M. Colmenero-Flores²  Antonio Montero²  Alfonso Perez-Martin²  Antonio Diaz-Espejo²  Virginia Hernandez-Santana²  Pablo Diaz-Rueda²  María D. Raya-Sereno³  Celia M. Rodriguez-Dominguez⁴ 

[1] Centro “Las Torres-Tomejil”, Instituto Andaluz de Investigación y Formación Agraria y Pesquera, Seville, Spain;Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain;School of Agricultural Engineering, CEIGRAM, Universidad Politécnica de Madrid, Madrid, Spain;School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia;

关键词: hydraulic allometry;    leaf hydraulic conductance;    leaf:sapwood area ratio;    leaf:root area ratio;    net photosynthesis rate;    stomatal conductance;   

DOI  :  10.3389/fpls.2019.00291

来源: DOAJ

【 摘 要 】

The hydraulic traits of plants, or the efficiency of water transport throughout the plant hydraulic system, could help to anticipate the impact of climate change and improve crop productivity. However, the mechanisms explaining the role of hydraulic traits on plant photosynthesis and thus, plant growth and yield, are just beginning to emerge. We conducted an experiment to identify differences in growth patterns at leaf, root and whole plant level among four wild olive genotypes and to determine whether hydraulic traits may help to explain such differences through their effect on photosynthesis. We estimated the relative growth rate (RGR), and its components, leaf gas exchange and hydraulic traits both at the leaf and whole-plant level in the olive genotypes over a full year. Photosynthetic capacity parameters were also measured. We observed different responses to water stress in the RGRs of the genotypes studied being best explained by changes in the net CO2 assimilation rate (NAR). Further, net photosynthesis, closely related to NAR, was mainly determined by hydraulic traits, both at leaf and whole-plant levels. This was mediated through the effects of hydraulic traits on stomatal conductance. We observed a decrease in leaf area: sapwood area and leaf area: root area ratios in water-stressed plants, which was more evident in the olive genotype Olea europaea subsp. guanchica (GUA8), whose RGR was less affected by water deficit than the other olive genotypes. In addition, at the leaf level, GUA8 water-stressed plants presented a better photosynthetic capacity due to a higher mesophyll conductance to CO2 and a higher foliar N. We conclude that hydraulic allometry adjustments of whole plant and leaf physiological response were well coordinated, buffering the water stress experienced by GUA8 plants. In turn, this explained their higher relative growth rates compared to the rest of the genotypes under water-stress conditions.

【 授权许可】

Unknown