Elevated CO₂concentration alleviates salinity stress in tomato plant

Abstract

Tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] plants were grown under potted conditions inside the greenhouse of Hiroshima University, Japan. The effects of salinity stress under either ambient or elevated CO 2 atmospheric conditions during the fruit-growth period were compared. Stem was the major sink organ for the carbon assimilates from the source leaves. A simple nondestructive micromorphometric technique was used to measure growth of these organs. The effect of salt stress under ambient air or elevated CO 2 concentration was studied on the apparent photosynthesis (source activity), partitioning 13 C, Na content, and antioxidative enzymes. Compared with the control (without salt), salt-stress treatment severely decreased whole-plant biomass. The treatment also depressed leaf photosynthesis and transport of 13 C assimilates; however, the impact of stress on these activities was alleviated under elevated CO 2 concentration and such alleviation was promoted when sink activity relative to source activity was higher, suggesting that sink activity is involved in alleviation of photosynthesis impaired from salinity. Catalase and ascorbate peroxidase activities increased by salinity stress but they decreased by elevated CO 2 . These results suggested that salinity stress suppresses stem growth in tomato plants; however, the adverse effect is alleviated under elevated CO 2 concentration due not to elevation of source activity in leaves but to activation of sink activity, probably owing to improvement of oxidative stress as well as the water status through stomatal closure at high CO 2 concentration.

High atmospheric carbon dioxide-dependent alleviation of salt stress is linked to RESPIRATORY BURST OXIDASE 1 (RBOH1)-dependent H2O2production in tomato (Solanum lycopersicum)

“…S1 ). These findings agree with those of other studies concerning the relationships between elevated CO 2 levels and high salinity in tomato and other plant species Takagi et al , 2009 ; ( Del Amor, 2013 ; Zaghdoud et al , 2013 ; Pinero et al , 2014 ; Yu et al , 2015 ). High CO 2 levels decreased leaf transpiration rates and stomatal conductance values, even in plants grown with high salt ( Fig.…”

“…In addition to increasing photosynthetic CO 2 assimilation rates, growth with high atmospheric CO 2 levels can mitigate against the negative impacts of abiotic stresses ( Ameye et al , 2012 ; Bauweraerts et al , 2013 ; Zinta et al , 2014 ). For example, growth under high CO 2 led to enhanced tolerance to salinity, Fe deficiency and increased resistance to (hemi) biotrophic microbes such as tobacco mosaic virus and Pseudomonas syringae in tomato ( Solanum lycopersicum ; Jin et al , 2009 ; Takagi et al , 2009 ; Del Amor, 2013 ; Li et al , 2015 ). In contrast, growth under elevated CO 2 enhanced susceptibility to the necrotrophic pathogen, Botrytis cinerea ( Zhang et al , 2015 ).…”

Analyzing the significance of defoliation in growth, photosynthetic compensation and source-sink relations

“…The increase in photosynthesis under higher CO 2 was due to reduced source activity by partial defoliation, whereas in intact plants the increase in CO 2 increased source activity and photosynthesis remains unchanged. Takagi et al (2009) have shown that net photosynthesis of the defoliated plant increased by elevated CO 2 (100 Pa) by about 35% relative to that in the ambient air and down regulation was not observed during the 14-day experimental period in tomato (Lycopersicum esculentum L.). Plants may respond positively to moderate defoliation under elevated CO 2 , but responsiveness decreases with high frequency of defoliation (Wand and Midgley 2004).…”

Alocação de fotoassimilados marcados e relação fonte-dreno em figueiras cv. Roxo de Valinhos. 1. Relação fonte e dreno

“…As temperaturas consideradas moderadamente altas (35 a 42°C) podem causar danos diretos à fotossíntese (Wise et al, 2004), por provocarem mudanças na membrana do tilacóide e alterarem as propriedades físico-químicas e também a organização funcional dessas estruturas celulares (Streit et al, 2005). Em elevadas temperaturas, a taxa máxima de assimilação de carbono pode ser inibida por diminuir a condutância estomática (Takagi et al, 2009). Além disso, altas temperaturas podem levar ao aumento da respiração mitocondrial e da fotorespiração.…”