Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability

Drought deficit inhibits oat growth and yield. Fulvic acid (FA) can enhance plant stress tolerance, but its effects on regulating the ascorbate–glutathione cycle, chlorophyll synthesis, and carbon–assimilation ability remain unclear. Therefore, this study aimed to elucidate the physiological mechani...

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Main Authors: Shanshan Zhu, Junzhen Mi, Baoping Zhao, Yongjian Kang, Mengxin Wang, Jinghui Liu
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/5/1153
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author Shanshan Zhu
Junzhen Mi
Baoping Zhao
Yongjian Kang
Mengxin Wang
Jinghui Liu
author_facet Shanshan Zhu
Junzhen Mi
Baoping Zhao
Yongjian Kang
Mengxin Wang
Jinghui Liu
author_sort Shanshan Zhu
collection DOAJ
description Drought deficit inhibits oat growth and yield. Fulvic acid (FA) can enhance plant stress tolerance, but its effects on regulating the ascorbate–glutathione cycle, chlorophyll synthesis, and carbon–assimilation ability remain unclear. Therefore, this study aimed to elucidate the physiological mechanisms of the FA regulation of drought tolerance in oats and its relationship with growth and yield using the drought-resistant variety Yanke 2 and the drought-sensitive variety Bayou 9. The effects of FA on growth and yield, the antioxidant system, chlorophyll synthesis, and carbon–assimilation capacity of oats under drought stress were investigated by systematically assessing changes in morphogenesis, ascorbate–glutathione cycle, chlorophyll and its intermediates, carbon–assimilation enzyme activities, and carbohydrate metabolism. The results showed that under drought stress, FA treatment significantly promoted oat growth (leaf area, dry matter) and yield, elevated glutathione peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase activities, reduced ascorbic acid, and reduced glutathione content. In addition, FA increased chlorophyll, as well as magnesium protoporphyrin IX, protoporphyrin IX, and protochlorophyllin acid ester content, enhanced 1,5-bisphosphate ribulose carboxylase, 1,5-bisphosphate ribulose carboxylase enzyme, 1,7-bisphosphate sestamibiose heptulose esterase, 1,6-bisphosphate fructose aldolase, sucrose synthase, sucrose phosphate synthase, acid invertase, and neutral invertase activities, and increased sucrose, glucose, and fructose content. Overall, fulvic acid (FA) alleviates drought-induced damage in oats by enhancing the ascorbate–glutathione cycle, promoting chlorophyll biosynthesis, and improving carbon assimilation and carbohydrate metabolism. The drought-sensitive variety (Yanke 2) was more effective in application compared to the drought-resistant variety (Bayou 9). This research provides valuable insight into its potential as a biostimulant under abiotic stress.
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spelling doaj-art-ece435853cf341dfa5803f16706828fe2025-08-20T02:33:36ZengMDPI AGAgronomy2073-43952025-05-01155115310.3390/agronomy15051153Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation AbilityShanshan Zhu0Junzhen Mi1Baoping Zhao2Yongjian Kang3Mengxin Wang4Jinghui Liu5National Agricultural Scientific Research Outstanding Talents and Their Innovation Team, Inner Mongolia Grassland Talents Innovation Team, Coarse Cereals Industry Collaborative Innovation Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaNational Agricultural Scientific Research Outstanding Talents and Their Innovation Team, Inner Mongolia Grassland Talents Innovation Team, Coarse Cereals Industry Collaborative Innovation Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaNational Agricultural Scientific Research Outstanding Talents and Their Innovation Team, Inner Mongolia Grassland Talents Innovation Team, Coarse Cereals Industry Collaborative Innovation Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaInner Mongolia Collegiate Oat Engineering Research Center, Inner Mongolia Coarse Grains Engineering Technology Research Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaNational Agricultural Scientific Research Outstanding Talents and Their Innovation Team, Inner Mongolia Grassland Talents Innovation Team, Coarse Cereals Industry Collaborative Innovation Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaNational Agricultural Scientific Research Outstanding Talents and Their Innovation Team, Inner Mongolia Grassland Talents Innovation Team, Coarse Cereals Industry Collaborative Innovation Center, Inner Mongolia Agricultural University, Hohhot 010018, ChinaDrought deficit inhibits oat growth and yield. Fulvic acid (FA) can enhance plant stress tolerance, but its effects on regulating the ascorbate–glutathione cycle, chlorophyll synthesis, and carbon–assimilation ability remain unclear. Therefore, this study aimed to elucidate the physiological mechanisms of the FA regulation of drought tolerance in oats and its relationship with growth and yield using the drought-resistant variety Yanke 2 and the drought-sensitive variety Bayou 9. The effects of FA on growth and yield, the antioxidant system, chlorophyll synthesis, and carbon–assimilation capacity of oats under drought stress were investigated by systematically assessing changes in morphogenesis, ascorbate–glutathione cycle, chlorophyll and its intermediates, carbon–assimilation enzyme activities, and carbohydrate metabolism. The results showed that under drought stress, FA treatment significantly promoted oat growth (leaf area, dry matter) and yield, elevated glutathione peroxidase, ascorbate peroxidase, glutathione reductase, and dehydroascorbate reductase activities, reduced ascorbic acid, and reduced glutathione content. In addition, FA increased chlorophyll, as well as magnesium protoporphyrin IX, protoporphyrin IX, and protochlorophyllin acid ester content, enhanced 1,5-bisphosphate ribulose carboxylase, 1,5-bisphosphate ribulose carboxylase enzyme, 1,7-bisphosphate sestamibiose heptulose esterase, 1,6-bisphosphate fructose aldolase, sucrose synthase, sucrose phosphate synthase, acid invertase, and neutral invertase activities, and increased sucrose, glucose, and fructose content. Overall, fulvic acid (FA) alleviates drought-induced damage in oats by enhancing the ascorbate–glutathione cycle, promoting chlorophyll biosynthesis, and improving carbon assimilation and carbohydrate metabolism. The drought-sensitive variety (Yanke 2) was more effective in application compared to the drought-resistant variety (Bayou 9). This research provides valuable insight into its potential as a biostimulant under abiotic stress.https://www.mdpi.com/2073-4395/15/5/1153oatdrought deficitfulvic acidmorphological indexphysiological biochemistry
spellingShingle Shanshan Zhu
Junzhen Mi
Baoping Zhao
Yongjian Kang
Mengxin Wang
Jinghui Liu
Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
Agronomy
oat
drought deficit
fulvic acid
morphological index
physiological biochemistry
title Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
title_full Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
title_fullStr Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
title_full_unstemmed Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
title_short Fulvic Acid Enhances Oat Growth and Grain Yield Under Drought Deficit by Regulating Ascorbate–Glutathione Cycle, Chlorophyll Synthesis, and Carbon–Assimilation Ability
title_sort fulvic acid enhances oat growth and grain yield under drought deficit by regulating ascorbate glutathione cycle chlorophyll synthesis and carbon assimilation ability
topic oat
drought deficit
fulvic acid
morphological index
physiological biochemistry
url https://www.mdpi.com/2073-4395/15/5/1153
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