Impact of Limited Irrigation on Fruit Quality and Ethylene Biosynthesis in Tomato: A Comprehensive Analysis of Physical, Biochemical, and Metabolomic Traits

Abstract

Water scarcity and climate change pose significant challenges to sustainable agriculture, emphasizing the need for optimized irrigation practices. This study evaluates the impact of limited irrigation (0.45 L/day per plant) compared to a control (0.87 L/day per plant) on tomato fruit quality and metabolic responses. Limited irrigation enhanced fruit flavor by reducing the pH from 4.2 to 3.4 and improved cellular integrity, with electrolyte leakage decreasing from 50% to 26%. Antioxidant levels increased, with the vitamin C content rising from 49 to 64 mg 100 g^-1 FW, while glucose and fructose accumulation contributed to improved sweetness. Notably, limited irrigation suppressed ethylene biosynthesis, reducing methionine, ACC, ACO activity, and ethylene production, which are key regulators of ripening and senescence. This suppression suggests the potential for extending shelf life and delaying over-ripening. These findings underscore the dual benefits of limited irrigation: enhancing fruit quality and supporting sustainable water use. This research provides a viable strategy for optimizing tomato production and postharvest quality in water-limited regions.

Keywords: biochemical composition; ethylene production; limited irrigation; metabolome analysis; tomato quality.

Figure 1

Comparison of physical parameters between tomato fruits grown under normal and limited irrigation conditions, including fruit weight (A), fruit height (B), fruit diameter (C), fruit volume (D), fruit density (E), and fruit firmness (F). CK: control, and WS: water stress. The data, presented as mean ± SD, represent the average of 10 individual fruits (n = 10) for each condition. Statistical significance is indicated by ns (not significant), * p < 0.05, and **** p < 0.0001.

Figure 2

Comparison of pericarp thickness in tomato fruits under normal irrigation (control) and limited irrigation (water stress) conditions. The data, presented as mean ± SD, represent the average of 10 individual fruits (n = 10) per condition. Statistical significance is indicated by ** p < 0.01. This analysis highlights the impact of irrigation levels on the structural characteristics of the tomato pericarp, which may be crucial for fruit quality and marketability.

Figure 3

Comparison of fruit color (*a value) in tomato fruits under normal irrigation (control) and limited irrigation (water stress) conditions. The data, presented as mean ± SD, represent the average of 10 individual fruits (n = 10) per condition. Statistical significance is indicated by ns (not significant). This analysis examines the effects of irrigation levels on the color quality of tomatoes, which can be a key factor in consumer preferences and marketability.

Figure 4

Ethylene-related parameters in tomato fruits under normal (control) and limited irrigation (water stress) conditions: methionine (A), ACC (B), ACO activity in water (C), ACO activity in 1 mM ACC (D), ACO activity in 10 mM ACC (E), ACO activity in 100 mM ACC (F), and ethylene production (G). The data, presented as mean ± SD, represent the average of 10 individual fruits (n = 10) for each condition. Statistical significance is indicated by * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001. This analysis investigates the impact of limited irrigation on key ethylene-related parameters, which influence ripening and postharvest quality in tomatoes.

Figure 5

Ethylene production over one month (A) and average carbon dioxide production (B) in tomato fruits under control (CK) and limited irrigation (WS) conditions. The data are presented as mean ± SD, with 10 individual fruits (n = 10) per treatment. Statistical significance is indicated by ** p < 0.01, *** p < 0.001, and **** p < 0.0001. This analysis explores how limited irrigation affects ethylene and carbon dioxide production, two key parameters related to fruit ripening and postharvest behavior.

Figure 6

Effects of limited irrigation on ethylene biosynthesis in tomato fruits. Ethylene-related parameters measured include methionine, ACC, ACO in water, ACO in 1 mM ACC, ACO in 10 mM ACC, ACO in 100 mM ACC, and ethylene production under control (CK) and limited irrigation (WS) conditions. The data are presented as mean ± SD, with 10 individual fruits (n = 10) per treatment. Statistical significance is indicated by * p < 0.05, *** p < 0.001, and **** p < 0.0001. This analysis highlights how limited irrigation influences key ethylene biosynthesis parameters, potentially affecting fruit ripening and quality.

Figure 7

Biochemical traits of tomato fruits under normal and limited irrigation conditions: pH (A), Brix (B), vitamin C content (C), and electrolyte leakage (D). CK: control, and WS: limited irrigation treatment. The data, presented as mean ± SD, represent the average of 10 individual fruits (n = 10) for each condition. Statistical significance is indicated by ns (not significant) and * p < 0.05, **** p < 0.0001. This figure illustrates the impact of limited irrigation on key biochemical traits, highlighting potential changes in fruit quality and nutritional value.

Figure 8

Principal Component Analysis (PCA) of metabolite profiles in tomato fruits under control and limited irrigation treatments. WS: limited irrigation, and CK: control. The PCA was performed to explore the differences in metabolite composition between the two treatment groups, providing insights into the metabolic changes induced by water stress. Each point represents a sample, and the clustering of data points reflects the similarity in metabolite profiles.

Figure 9

Irrigation per plant in both normal and limited irrigation treatments (A) and minimum and maximum room temperature (B). WS: limited irrigation.