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Main conclusion <p>Wheat cultivars’ contradictory responses to drought stress regarding dry matter remobilization are primarily due to differences in assimilate partitioning to mobilizable non-structural carbohydrates in the stem.</p> Abstract <p>Accumulation and remobilization of stem reserves are crucial for maintaining wheat yield stability under drought stress (DS). Cultivars respond differently to DS in dry matter remobilization (DMR), but the reasons are unclear. This study aimed to identify factors driving cultivar-specific variation in DMR by examining two wheat cultivars with contrasting drought tolerance and DMR characteristics under well-watered (70% field capacity) and DS (50% field capacity, imposed from stem elongation onward) conditions. Data showed that DS significantly improved DMR efficiency and the contribution of stem reserves to grain yield by 26.78 and 44.53% in Shabrang (drought-resistant) and by 13.97 and 26.80% in Dez (drought-sensitive), respectively. Dez demonstrated a 36.04% reduction in DMR, associated with severe source limitations and reduced sink size, while Shabrang increased by 5.40% under DS. Improved DMR in Shabrang was initially linked to a 12.39% increase in the proportion of stem water-soluble carbohydrates (WSC) to stem dry weight, a pattern not observed in Dez. Shabrang also exhibited better chlorophyll retention and Fv/Fm values, a larger green flag leaf area, greater WSC accumulation, higher endosperm cell division and number, and a faster grain-filling rate. In addition, the relative expression of sucrose–fructan 6-fructosyltransferase and fructan 1-exohydrolase w3 was higher in Shabrang during the examined periods. Overall, differences in cultivars’ DMR under DS are mainly driven by variations in assimilate partitioning, source–sink strength, and carbohydrate metabolism. Enhancing these traits could improve DMR, stabilize wheat yield under water-limited conditions, and support sustainable crop improvement strategies in the face of climate change.</p>

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Assimilate partitioning to stem non-structural carbohydrates and their remobilization to developing grains in spring wheat under drought stress conditions

  • 期刊论文

  • 发表日期：

    2025年10月25日

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  • Pouria Mostafaie,
  • Sara Sadat Afjeh,
  • Ali Ahmadi,
  • Fariba Abooie

摘要

Main conclusion

Wheat cultivars’ contradictory responses to drought stress regarding dry matter remobilization are primarily due to differences in assimilate partitioning to mobilizable non-structural carbohydrates in the stem.

Abstract

Accumulation and remobilization of stem reserves are crucial for maintaining wheat yield stability under drought stress (DS). Cultivars respond differently to DS in dry matter remobilization (DMR), but the reasons are unclear. This study aimed to identify factors driving cultivar-specific variation in DMR by examining two wheat cultivars with contrasting drought tolerance and DMR characteristics under well-watered (70% field capacity) and DS (50% field capacity, imposed from stem elongation onward) conditions. Data showed that DS significantly improved DMR efficiency and the contribution of stem reserves to grain yield by 26.78 and 44.53% in Shabrang (drought-resistant) and by 13.97 and 26.80% in Dez (drought-sensitive), respectively. Dez demonstrated a 36.04% reduction in DMR, associated with severe source limitations and reduced sink size, while Shabrang increased by 5.40% under DS. Improved DMR in Shabrang was initially linked to a 12.39% increase in the proportion of stem water-soluble carbohydrates (WSC) to stem dry weight, a pattern not observed in Dez. Shabrang also exhibited better chlorophyll retention and Fv/Fm values, a larger green flag leaf area, greater WSC accumulation, higher endosperm cell division and number, and a faster grain-filling rate. In addition, the relative expression of sucrose–fructan 6-fructosyltransferase and fructan 1-exohydrolase w3 was higher in Shabrang during the examined periods. Overall, differences in cultivars’ DMR under DS are mainly driven by variations in assimilate partitioning, source–sink strength, and carbohydrate metabolism. Enhancing these traits could improve DMR, stabilize wheat yield under water-limited conditions, and support sustainable crop improvement strategies in the face of climate change.