The Associated With Carbon Conversion Rate and Source-Sink Enzyme Activity in Tomato Fruit Subjected to Water Stress and Potassium Application.

Anrong Luo,Jinliang Chen,Chenni Zhou

doi:10.3389/fpls.2021.681145

Anrong Luo, Jinliang Chen + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2021.681145

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Abstract

Carbon metabolism in higher plants is a basic physiological metabolism, and carbon allocation and conversion require the activity of various enzymes in metabolic processes that alter the content and overall composition of sugars in the sink organ. However, it is not known how various enzymes affect carbon metabolism when tomato plants are subjected to water stress or treated with potassium. Although the process of carbon metabolism is very complex, we used the carbon conversion rate to compare and analyze the enzyme activities related to sugar metabolism and find out which carbon conversion rate are the most important. Results showed that water stress and potassium increased carbon import flux in the fruit, which was beneficial to carbon accumulation. Water deficit increased the activity of sucrose synthase (SuSy) and starch phosphorylase (SP) and decreased the activity of sucrose phosphate synthase (SPS) and adenosine diphosphate glucose pyrophosphorylase (AGPase) in the source. Water stress increased the activity of acid invertase (AI), SuSy and SP but decreased the activity of AGPase in the sink. Potassium modified the balance of enzymes active in sugar and starch metabolism by increasing the activity of AI, SuSy, SPS and SP and significantly decreasing the activity of AGPase, resulting in increase of hexose. Canonical correlational analysis revealed that the carbon conversion rate was mainly affected by the relative rate of conversion of sucrose to fructose and glucose [p1(t)] and glucose to starch [p5m(t)]. SuSy and AGPase had the greatest effect on enzyme activity in the fruit; respectively regulated p1(t) and p5m(t).

Highlights

Carbon metabolism is a basic physiological metabolism in high plants, but its process is complicated (Winter and Huber, 2000)
sucrose synthase (SuSy) activity was greater in water deficit treatments (WD) than in full irrigation (CK) regardless of whether potassium was applied or not; regardless of water deficit or full irrigation, the SuSy activity of potassium treatment (K1) was significantly greater than without potassium treatment (K0), with was greatest in the water deficit and potassium treatments but least in CK
The sucrose phosphate synthase (SPS) activity of WD was significantly less than CK regardless of whether potassium was applied or not; whether full irrigation or water deficit conditions, K1 was greater than K0

Summary

Introduction

Carbon metabolism is a basic physiological metabolism in high plants, but its process is complicated (Winter and Huber, 2000). Sugar metabolism is regulated by key enzymes, and water stress affects the activity of key enzymes in the metabolism of carbon assimilates (Mafakheri et al, 2011). Nutrients, such as potassium, promote the conversion and transport of photosynthesis products, which include sugars (Deeken et al, 2002; Walter and Difonzo, 2007). Enzyme activity, and sugar metabolism are all influenced by potassium (Philippe et al, 2006; Almeselmani et al, 2009; Zahoor et al, 2017b; Omondi et al, 2019), and so both water and mineral nutrients are key factors in determining carbon allocation (Reynolds and Tuberosa, 2008; Rosa et al, 2009; Witt et al, 2012)

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