Effects of Combined High Temperature and Waterlogging Stress at Booting Stage on Root Anatomy of Rice (Oryza sativa L.)

Abstract

In recent years, the alternating occurrence of high temperature and waterlogging disasters in South China has seriously reduced the yield of single cropping rice. Studying the changes in anatomical structure of the rice root system could provide theoretical basis for understanding the mechanisms of high temperature and waterlogging stress. To examine interactions between temperature and waterlogging stress, an experiment was set up in a growth chamber consisting of two temperatures (moderate, 30–34 °C and high, 35–38 °C) with three depths of flooding (0–5, 10 and 15 cm). Treatments commenced at the booting stage and lasted five days, after which all treatments were returned to a 0–5 cm flooding depth and the same temperature regime. Observations were made immediately after cessation of treatments, then after 5, 10 and 20 d to test the effect of treatments on subsequent root anatomical development. The low-stress control (0–5 cm, medium temperature) showed no change with time in aerenchyma area, thickness of the outer root, stele diameter, and the number nor diameter of xylem vessels. Root diameter and stele diameter under the high-stress control (0–5 cm, high temperature) were decreased by 29.09% and 15.28%, respectively, at the booting stage, whereas the high stress control (15 cm, high temperature) affected only the vessel diameter, reducing it by 14.11% compared with that in the low-stress control (0–5 cm, medium temperature). Compared to the high-stress control (0–5 cm, high temperature), the interaction of high temperature and waterlogging stress alleviated the inhibiting effect of the changes in the root system, especially after the end of the stress. We thought that waterlogging could reduce the damage of high temperature on rice root growth. Low water depth waterlogging has little effect on rice root system and aerenchyma area root diameter at 0, 5, 10 and 20 d after the stress ended, and the thickness of the outer root, stele diameter and the number and diameter of vessels at 0 d under M15 (15 cm, medium temperature) had no significant difference compared with M5 (0–5 cm, medium temperature). However, the increase in rice root diameter, stele diameter, thickness of the outer root cortex depth and vessel diameter were inhibited under high temperature stress at the booting stage. Root diameter and stele diameter under H5 (0–5 cm, high temperature) were decreased by 29.09% and 15.28%, respectively, at the booting stage, whereas H15 (15 cm, high temperature) affected only the vessel diameter, reducing it by 14.11% compared with that in the M5. Compared to H5, the interaction of high temperature and waterlogging stress alleviated the inhibiting effect of the changes in the root system, especially after the end of the stress. We thought that waterlogging could lighten the damage of high temperature on rice root growth.

Low‐temperature stress during the flowering period alters the source–sink relationship and grain quality in field‐grown late‐season rice

“…The increased N/FS ratio in 2020 compared to 2019 was also attributable to an increase in N uptake. Crop nutrient uptake is closely related to root growth (Huang, Chen, et al., 2016; Huang, Shan, et al., 2016), which is affected by several environmental factors including temperature (Zhen et al., 2020). The optimum temperature for root growth is 26.0–27.6°C in rice (Sánchez et al., 2014).…”

Modelling Waterlogging Impacts on Crop Growth: A Review of Aeration Stress Definition in Crop Models and Sensitivity Analysis of APSIM

“…Further, combined stresses involving aeration stress have not had as much attention as other stresses. Studies on combined stresses that include aeration stress are aeration and salt stress in tomatoes [63], waterlogging and pathogen (Fusarium poae) stress on wheat and barley [64], and temperature and waterlogging stress on rice [65]. Given that concurrent stresses on a crop can produce a synergistic effect, the multiplicative and the most limiting stress approaches in models may be unrealistic and further research is needed to understand the various stress response pathways for combined stresses.…”

Response of root and root hair phenotypes of cotton seedlings under high temperature revealed with RhizoPot

“…The root phenotypes of crops can be altered to improve their high temperature resistance, which constitutes an important phenotypic characteristic. High temperature not only inhibits root development (Calleja-Cabrera et al, 2020;Hund et al, 2008) but also affects the absorption of water by the roots and accelerates root senescence, causing the lignified roots to elongate to almost the tip and resulting in a reduction in the root absorption area and rate of nutrient absorption (Zhen et al, 2020). Martins et al (2017) showed that, as the temperature increases, the roots could elongate faster to protect the meristems.…”

“…(2019) found that the root length, root surface area, and root volume all decreased significantly. Under high temperature stress, the root diameter and root cortex thickness of rice were both significantly inhibited ( Zhen et al., 2020 ). A study also revealed that high temperatures reduced the root dry weight and R/S ratio but increased the specific root length, specific root surface area, and specific root volume ( Tahir et al., 2008 ).…”