Abscisic acid(ABA),hydrogen peroxide(H_(2)O_(2)) and ascorbate(AsA)–glutathione(GSH)cycle are widely known for their participation in various stresses.However,the relationship between ABA and H_(2)O_(2) levels and th...Abscisic acid(ABA),hydrogen peroxide(H_(2)O_(2)) and ascorbate(AsA)–glutathione(GSH)cycle are widely known for their participation in various stresses.However,the relationship between ABA and H_(2)O_(2) levels and the AsA–GSH cycle under drought stress in wheat has not been studied.In this study,a hydroponic experiment was conducted in wheat seedlings subjected to 15%polyethylene glycol(PEG)6000–induced dehydration.Drought stress caused the rapid accumulation of endogenous ABA and H_(2)O_(2) and significantly decreased the number of root tips compared with the control.The application of ABA significantly increased the number of root tips,whereas the application of H_(2)O_(2) markedly reduced the number of root tips,compared with that under 15%PEG-6000.In addition,drought stress markedly increased the DHA,GSH and GSSG levels,but decreased the AsA levels,AsA/DHA and GSH/GSSG ratios compared with those in the control.The activities of the four enzymes in the AsA–GSH cycle were also markedly increased under drought stress,including glutathione reductase(GR),ascorbate peroxidase(APX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR),compared with those in the control.However,the application of an ABA inhibitor significantly inhibited GR,DHAR and APX activities,whereas the application of an H_(2)O_(2) inhibitor significantly inhibited DHAR and MDHAR activities.Furthermore,the application of ABA inhibitor significantly promoted the increases of H_(2)O_(2) and the application of H_(2)O_(2) inhibitor significantly blocked the increases of ABA,compared with those under 15% PEG-6000.Taken together,the results indicated that ABA and H_(2)O_(2) probably interact under drought stress in wheat;and both of them can mediate drought stress by modulating the enzymes in AsA–GSH cycle,where ABA acts as the main regulator of GR,DHAR,and APX activities,and H_(2)O_(2) acts as the main regulator of DHAR and MDHAR activities.展开更多
The objective of this study was to understand the morphological,physiological,and molecular responses of wheat roots to nitrate supply at seedling stage.Two wheat genotypes,Jimai 22 and Shannong 15,were grown in Hoagl...The objective of this study was to understand the morphological,physiological,and molecular responses of wheat roots to nitrate supply at seedling stage.Two wheat genotypes,Jimai 22 and Shannong 15,were grown in Hoagland＇s nutrient solution with different nitrate levels at seedling stage.Results indicated that the plant dry weight and N accumulation increased with the increase of nitrate supply.The number of axial root,total uptake area （TUA）,and active uptake area （AUA） increased with more nitrate supply.Correlation analysis indicated that significant positive correlations existed between N accumulation and dry weight,N accumulation and AUA,and N accumulation and AUA/TUA.Although,the expressions of NRT2.1,NRT2.2,and NRT2.3 decreased with nitrate supply increased,the expressions of NRT1,NRT2.1,and NRT2.3 could maintain high level at N3 treatment.The free amino acid and NO3- content in shoot also increased with the increased nitrate application,but no significant difference was found in root among the treatments.These results implied that the increase of N uptake by nitrate supply was due to the morphological and physiological responses of wheat roots and the high expression level of TaNRT genes.Similarly,the contribution of morphological,physiological,and molecular parameters was different between two genotypes of wheat.展开更多
The dynamic relationship of dry matter accumulation and distribution between winter wheat root and shoot was studied under different soil water conditions. The dry matter accumulation in root was greatly influenced by...The dynamic relationship of dry matter accumulation and distribution between winter wheat root and shoot was studied under different soil water conditions. The dry matter accumulation in root was greatly influenced by water stress, so as to the final root weight of the treatment with 40% field moisture capacity(FMC) was less than 1/4 of that of the treatment with 80% FMC on average. Water stress during the 3-leaf stage to the tillering stage had the greatest influence on root, and the influence of water stress during the jointing stage to the booting stage on shoot was greater than root. However, water stress during the tillering stage to the booting stage had a balanced effect on root and shoot, and the proportion of dry matter that distributed to root and shoot was almost the same after rewatering. Water recovery during the jointing stage to booting stage could promote R/S, but the increasing degree was related to the duration of water limitation. Soil water condition had the lowest effect on R/S during the flowering stage to the filling stage and the maximal effect on R/S during the jointing stage to the heading stage, R/S of 40% FMC treatment was 20.93 and 126.09% higher than that of 60% FMC and 80% FMC treatments respectively at this period.展开更多
Differential expression of gene in iron-efficient wheat cultivar Jing411 and iron-inefficient cul-tivar SanshumaiS under iron-deficiency and iron-sufficiency conditions was revealed by differential display reverse tra...Differential expression of gene in iron-efficient wheat cultivar Jing411 and iron-inefficient cul-tivar SanshumaiS under iron-deficiency and iron-sufficiency conditions was revealed by differential display reverse transcript PCR (DDRT-PCR) method. Northern blotting was carried out using ATP-binding transporter (ABC) cDNA obtained from DDRT-PCR products of the cultivar Jing411 as probe. Our results suggested that ABC gene expression was suppressed under iron-deficiency condition.展开更多
The equilibrium between root, shoot and growth stability under different soil water conditions were investigated in a tube experiment of winter wheat. The water supplying treatments included： sufficient irrigation at...The equilibrium between root, shoot and growth stability under different soil water conditions were investigated in a tube experiment of winter wheat. The water supplying treatments included： sufficient irrigation at whole growth phase, moderate deficiency irrigation at whole growth phase, serious deficiency irrigation at whole growth phase, sufficient irrigation at jointing stage, tillering stage, flowering stage, and fillering respectively, after moderate and serious water deficit during their previous growth stage. Root and shoot biomass were measured. On the basis of the cooperative root-shoot interactions model, the equilibrium and growth stability were studied on the strength of the kinetics system theory. There was only one varying equilibrium point between the root and shoot over the life time of the winter wheat plant. Water stress prolonged the duration of stable growth, the more serious the water deficit, the longer the period of stable growth. The duration of stable growth was shortened and that of unstable growth was prolonged after water recovery. The growth behavior of the plants exposed to moderate water deficit shifted from stable to unstable until the end of the growth, after rewatering at flowering. In the life-time of the crop, the root and shoot had been adjusting themselves in structure and function so as to maintain an equilibrium, but could not achieve the equilibrium state for long. They were always in an unbalanced state from the beginning to the end of growth. This was the essence of root-shoot equilibrium. Water stress inhibited the function of root and shoot, reduced root shoot interactions, and as a result, the plant growth gradually tended to stabilize. Rewatering enhanced root shoot interactions, prolonged duration of instable growth. Rewatering at flowering could upset the inherent relativity during the long time of stable growth from flowering to filling stage, thus leading to unstable growth and enhanced dry matter accumulating rate in the whole plant.展开更多
To reveal the period and after-effect of soil water stress on winter wheat, the article employs the experiment results carried out in the greenhouse. The results showed that the root-restricted weights varied with str...To reveal the period and after-effect of soil water stress on winter wheat, the article employs the experiment results carried out in the greenhouse. The results showed that the root-restricted weights varied with stress degrees and stress times during and after water stressing. In the course of stress, the chief reason resticting the weight of root was the stress intensity at this time, and that of severe stress treatment was larger than that of mild stress treatment. After water stress was relieved, the results of the after-effect of soil water stress on root growth were that, the stress intensity of short-time and mild stress was larger than that of long-time and severe stress. Comparing two-stage stress intensities, root-restricted weight resulted from after-effect intensity of stress under all of the short-time treatment, and the mild and the long-time stress treatments, while that resulted from the period stress intensity under the severe and the long-time stress treatments. In general, the effects of water stress on root were attributed to the three factors, a formed basis in the previous stage, the after-effect of water condition before this stage and influence of water in this stage, which lead to the characters of root in the whole growth stage.展开更多
Effects of calcium on ATPase activities, lipid contents, and fatty acid compositions of plasma membrane from wheat roots were assayed under aluminum stress. The results showed that the increase of calcium concentr...Effects of calcium on ATPase activities, lipid contents, and fatty acid compositions of plasma membrane from wheat roots were assayed under aluminum stress. The results showed that the increase of calcium concentration in the nutrient solution increased the activity of H + ATPase and the phospholipid content, decreased the activity of Ca 2+ ATPase and the galactolipid of plasma membrane. Owing to the decrease of linolenic acid content, the index of unsaturated fatty acid (IUFA) and index of double bond (DBI) decreased in Altas66. The IUFA and DBI of plasma membrane from Scout66 roots increased because its linolenic acid content increased obviously and its palmitic acid content decreased apparently.展开更多
[ Objective ] This study aimed to investigate the regulatory role of potassium levels in plant gene expression. [ Method ] By using wheat （ Triticum aesti- vum L. Beinong 9549） as experimental material, the protein ...[ Objective ] This study aimed to investigate the regulatory role of potassium levels in plant gene expression. [ Method ] By using wheat （ Triticum aesti- vum L. Beinong 9549） as experimental material, the protein expression in wheat roots under different levels of potassium was determined by two-dimensional elec- trophoresis （2-DE）. [ Result] Compared with the plants supplied with normal level of potassium, 152 protein spots in wheat roots under potassium deficiency con- dition showed significant differences （P 〈 0.05 ）, including 76 protein spots significantly up-regulated by more than twice and 76 protein spots significantly down- regulated by more than twice. After potassium deficiency treatment, the wheat plants were supplied with normal level of potassium for two weeks, which showed sig- nificant differences in 73 protein spots compared with the plants continuously supplied with normal level of potassium （ P 〈 0. 05 ）, including 36 protein spots signif- icantly up-regulated by more than twice and 37 protein spots significantly down-regulated by more than twice. [ Conclusion] This study indicates that potassium de- ficiency stress would lead to induction of a large number of specific proteins in wheat roots.展开更多
[Objective] The aim was to research the effect of concentration of NO-3-N on root vigor and rhizosphere pH of winter wheat seedlings under water culture.[Method]By selecting Hoagland's nutritional solution as cult...[Objective] The aim was to research the effect of concentration of NO-3-N on root vigor and rhizosphere pH of winter wheat seedlings under water culture.[Method]By selecting Hoagland's nutritional solution as cultural medium and winter wheat as material of experiment,on the basis,testing root vigor,nutrient solution NO-3 and change of pH values under the different level of disposal,such as high(containing NO-3-N 15 mmol/L),medium(containing NO-3-N 7.5 mmol/L)and lower(containing NO-3-N 2.5 mmol/L).[Result]The results of this research showed that the effect of different nitrogen level on the wastage of nutrient solution NO-3,the changes of pH values and root vigor is obvious under the hydroponics condition.[Conclusion]Though NO-3 is a safe nitrogen sources when it was supplied to plants too more,it would restrain assimilation on nitrate nitrogen farther,but when it was supplied to plants too little,it would lead to deficiency of NO-3 that plants uptake and decrease of root activity,so it isn't useful to wheat young seedling to absorb nitrogen nutrition.展开更多
A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and...A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and 80 mmol L-1 OTC. OTC is toxic to wheat. The wheat growth, especially wheat root was significantly decreased. Further OTC also significantly decreased root activity, chlorophyll contents, and photosynthetic parameters except for intercellular CO2 concentrations. The different responses of indicators such as root number, root activity and so on to OTC were also observed. The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC. The order of indicator sensitivity to OTC was root number stomatal conductance chlorophyll a total chlorophyll photosynthetic rates total surface area transpiration rate chlorophyll b fresh weight of root dry weight of root total length dry weight of shoot = fresh weight of shoot total volume. The root number was more sensitive than other indicators with the IC50 value of 7.1 mmol L-1 OTC, and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.展开更多
Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals （nHRS）, drought tolerance and water use efficiency of winter wheat （Triticu...Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals （nHRS）, drought tolerance and water use efficiency of winter wheat （Triticum aestivum）. The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots （1.06 and 0.94 mmol g-1 s-1, respectively）. The soil water content （SWC） at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants （61.1-44.6% field water capacity） than for intact root plants （57.9-46.1% field water capacity）. At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield （F PS II ）, the maximum photochemical efficiency of PS II （F v /F m ）, coefficient of photochemical quenching （qP）, and coefficient of non-photochemical quenching （NPQ）, in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency （WUE） than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.展开更多
Effects of root penetration restriction on the growth and Mn nutrition of different wheat genotypes were studied in paddy soils using a method of nylon net bags (400 mesh) buried in the soil. The results showed that t...Effects of root penetration restriction on the growth and Mn nutrition of different wheat genotypes were studied in paddy soils using a method of nylon net bags (400 mesh) buried in the soil. The results showed that the spatial distribution of Mn in paddy soils played an important role in the growth and Mn nutrition of wheat crops. In the treatment where wheat roots were restricted in the plough layer by nylon net bags, the symptoms of Mn deficiency in wheat occurred much earlier and more seriously than usual. Of the two tested wheat genotypes, 80-8 was tolerant to Mn deficiency while 3295 was sensitive to Mn deficiency, respectively. The restriction of root penetration intensified symptoms of Mn deficiency of the Mn-deficient sensitive genotype (3295). The experiment demonstrated that well-developed roots with a strong ability to penetrate into the Mn-rich deep soil layer might explain the better tolerance of Mn deficiency in the tolerant genotypes.展开更多
Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was con...Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was conducted from 2006 through 2008 in arid northwestern China to determine the effects of four tillage systems on soil properties, root development, water-use efficiency, and grain yield of winter wheat （Triticum aestivum L.）. The cultivar Fan 13 was grown under four tillage systems：conventional tillage （CT） without wheat stubble, no-tillage without wheat stubble mulching （NT）, no-tillage with wheat stubble standing （NTSS）, and no-tillage with wheat stubble mulching （NTS）. The soil bulk density （BD） under CT system increased gradually from sowing to harvest, but that in NT, NTSS, and NTS systems had little change. Compared to the CT system, the NTSS and NTS systems improved total soil water storage （0-150 cm） by 6.1-9.6 and 10.5- 15.3% before sowing, and by 2.2-8.9 and 13.0-15.1% after harvest, respectively. The NTSS and NTS systems also increased mean dry root weight density （DRWD） as compared to CT system. The NTS system significantly improved water-use efficiency by 17.2-17.5% and crop yield by 15.6-16.8%, and the NTSS system improved that by 7.8-9.6 and 7.0-12.8%, respectively, compared with the CT system. Our results suggested that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil bulk density, water storage, root system, and winter wheat yield.展开更多
Root growth traits for different wheat types varied during the growth cycle. The root system of 93 Zhong 6, which is a dwarf, big-ear variety, reached its highest density at anthesis, while the root density of Zhoumai...Root growth traits for different wheat types varied during the growth cycle. The root system of 93 Zhong 6, which is a dwarf, big-ear variety, reached its highest density at anthesis, while the root density of Zhoumai 13, a medium-type variety, demonsrated its highest value during the node elongation stage and decreased rapidly at later growth stages, which resulted in lower yield. The root density of Zhongyu 6 and 98 Zhong 18, high yield potential, multiple ears varieties, did not show observable variation in their root systems during their growth cycles.展开更多
The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation pe...The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation periods (2007-2009) in the fields of winter wheat in northern Poland. Every year on each plot of compared farming systems root rot occurred (Fusarium spp., Gaeumannomyces graminis and other fungi). For the period of 3 years the degree of disease injury on the roots of winter wheat grown in the conventional system in the vegetation period increased, while in the organic one remained on pretty the same level. On average a lot more affected roots, especially in the flowering stage, occurred on the winter wheat grown in the conventional system. Fusarium foot rot (Fusarium spp.) developed on the wheat during the entire vegetation period. It was the most dangerous root and foot rot disease (the highest indexes of injury). The mean degree of disease injury on leave sheath was on pretty the same level in the two farming systems, although in investigated vegetation periods differed a lot, whereas at the bases of stems the pathogen was on the higher level on the wheat in the conventional system. Also eyespot (Tapesia yallude) developed in the entire vegetation period of the winter wheat, but its intensity was much lower than in case of fusarium foot rot. Leave sheaths of the wheat grown in the conventional system were slightly stronger affected than those grown in the organic system. In the flowering stage the intensity of the disease in both farming systems became equal, while in the wax maturity it was considerably higher in the conventional system. Sharp eyespot (Rhizoctonia spp.) appeared relatively late and occurred only in two years of investigation. The intensiveness of the disease was definitely higher on the organic plots. Among the affected roots, taken in the stem elongation stage, from the organic system 28 cultures of fungi were isolated, and from the conventional one 24 colonies. Cereals pathogenic fungi amounted 35.8% of isolates obtained from the organic system and as many as 66.7% from the conventional system. Among the affected roots, taken in the flowering stage, from the organic system 68 cultures of fungi were isolated in all, and from the conventional one 25 colonies. Cereals pathogenic fungi amounted 38.2% of isolates obtained from the organic system and 56.0% from the conventional system. Among the affected stem bases, taken in the wax maturity stage, from the organic system 56 cultures of fungi were isolated in all, and from the conventional one 52 colonies. Cereals pathogenic fungi amounted 48.4% of isolates obtained from the organic system and 53.6% from the conventional system. In the case of all root and foot rot diseases of wheat grown in the organic system, an advantageous influence of greater biodiversity and number of various fungi species living in root proximity was noticed as opposed to the conventional system.展开更多
Aluminum （Al） toxicity often takes place in acidic soils with a pH of 5.5 or lower. Breeding and cultivation of Al tolerance wheat can partially protect wheat escaping from Al toxicity. The scarcity of the tolerant ...Aluminum （Al） toxicity often takes place in acidic soils with a pH of 5.5 or lower. Breeding and cultivation of Al tolerance wheat can partially protect wheat escaping from Al toxicity. The scarcity of the tolerant sources impedes the wheat breeding. In order to find new Al tolerance sources, we screened 173 bread wheat landraces from Tibet of China using hydroponic screening. It was indicated that： （1） There were diversities on the root regenerate length （RRL）. The RRL of a large of landraces were longer than 7.00 cm in pH 7 （58.38%） and pH 4.5 （66.47%）, but shorter than 5.00 cm in pH 4.5 ＋50μM Al^3＋ （80.93%）. The low pH showed either promotion or restraining effects depend on landraces, but Al toxicity under low pH only showed restraining effects on the root elongation. （2） There were also diversities on root tolerance index of low pH （RTI 1） or root aluminum tolerance index （RTI2） among cultivars. The RTI1 varied from a narrow range but with relatively high value （0.8722-1.2953） in comparison with that of RTI2 （0.3829-1.0058）, and the RTI1 of approximately 60% landraces was higher than 1.0000, the RTI2 of only 19.07% landraces was higher than 0.7000, suggesting that Al toxicity acted as an important factor for the reduction of the root elongation under acidic soils. （3） The RTI 1 of many wheats was higher than 1.0000, and As2256 and As2295 were the most tolerant for low pH, with RTI1 1.2953 and 1.2925, respectively. （4） Based on RTI2, seven wheats showed similar or higher tolerance to Al toxicity than Chinese Spring （CS）, a known tolerance wheat. Much better tolerance existed in landraces of As1543 and As1242, which can be used as the new parents for Al tolerant breeding.展开更多
Plants need to be efficient in nutrient management, especially when they face the temporal nutrient defficiencies. Understanding how crops respond to nitrogen （N） starvation would help in the selection of crop culti...Plants need to be efficient in nutrient management, especially when they face the temporal nutrient defficiencies. Understanding how crops respond to nitrogen （N） starvation would help in the selection of crop cultivars more tolerant to N deficiency. In the present work, the physiological responses of two wheat cultivars, Yannong 19 （YN） and Qinmai 11 （QM）, to N starvation conditions were investigated. The two cultivars differed in biomass and N rearrangement between shoots and roots during N starvation. QM allocated more N to roots and exhibited higher root/shoot biomass ratio than YN. However, tissue measurement indicated that both cultivars had similar nitrate content in leaves and roots and similar remobilization rate in roots. Microelectrode measurement showed that vacuolar nitrate activity （concentration） in roots of QM was lower than that in roots of YN, especially in epidermal cells. Nitrate remobilization rates from root vacuoles of two cultivars were also identical. Moreover, vacuolar nitrate remobilization rate was proportional to vacuolar nitrate activity. During N starvation, nitrate reductase activity （NRA） was decreased but there were no significant differences between the two cultivars. Nitrate efflux from roots reduced after external N removal and QM seemed to have higher nitrate efflux rate.展开更多
基金This research was funded by the National Key Research and Development Program of China(2023YFD2301505).
文摘Abscisic acid(ABA),hydrogen peroxide(H_(2)O_(2)) and ascorbate(AsA)–glutathione(GSH)cycle are widely known for their participation in various stresses.However,the relationship between ABA and H_(2)O_(2) levels and the AsA–GSH cycle under drought stress in wheat has not been studied.In this study,a hydroponic experiment was conducted in wheat seedlings subjected to 15%polyethylene glycol(PEG)6000–induced dehydration.Drought stress caused the rapid accumulation of endogenous ABA and H_(2)O_(2) and significantly decreased the number of root tips compared with the control.The application of ABA significantly increased the number of root tips,whereas the application of H_(2)O_(2) markedly reduced the number of root tips,compared with that under 15%PEG-6000.In addition,drought stress markedly increased the DHA,GSH and GSSG levels,but decreased the AsA levels,AsA/DHA and GSH/GSSG ratios compared with those in the control.The activities of the four enzymes in the AsA–GSH cycle were also markedly increased under drought stress,including glutathione reductase(GR),ascorbate peroxidase(APX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR),compared with those in the control.However,the application of an ABA inhibitor significantly inhibited GR,DHAR and APX activities,whereas the application of an H_(2)O_(2) inhibitor significantly inhibited DHAR and MDHAR activities.Furthermore,the application of ABA inhibitor significantly promoted the increases of H_(2)O_(2) and the application of H_(2)O_(2) inhibitor significantly blocked the increases of ABA,compared with those under 15% PEG-6000.Taken together,the results indicated that ABA and H_(2)O_(2) probably interact under drought stress in wheat;and both of them can mediate drought stress by modulating the enzymes in AsA–GSH cycle,where ABA acts as the main regulator of GR,DHAR,and APX activities,and H_(2)O_(2) acts as the main regulator of DHAR and MDHAR activities.
基金supported by the National Natural Science Foundation of China (30871477)the National Basic Research Program of China (973 Program,2009CB118602)the National Department of Public Benefit Research Foundation,China (200803037)
文摘The objective of this study was to understand the morphological,physiological,and molecular responses of wheat roots to nitrate supply at seedling stage.Two wheat genotypes,Jimai 22 and Shannong 15,were grown in Hoagland＇s nutrient solution with different nitrate levels at seedling stage.Results indicated that the plant dry weight and N accumulation increased with the increase of nitrate supply.The number of axial root,total uptake area （TUA）,and active uptake area （AUA） increased with more nitrate supply.Correlation analysis indicated that significant positive correlations existed between N accumulation and dry weight,N accumulation and AUA,and N accumulation and AUA/TUA.Although,the expressions of NRT2.1,NRT2.2,and NRT2.3 decreased with nitrate supply increased,the expressions of NRT1,NRT2.1,and NRT2.3 could maintain high level at N3 treatment.The free amino acid and NO3- content in shoot also increased with the increased nitrate application,but no significant difference was found in root among the treatments.These results implied that the increase of N uptake by nitrate supply was due to the morphological and physiological responses of wheat roots and the high expression level of TaNRT genes.Similarly,the contribution of morphological,physiological,and molecular parameters was different between two genotypes of wheat.
基金supported by the National Natural Science Foundation of China(49971042).
文摘The dynamic relationship of dry matter accumulation and distribution between winter wheat root and shoot was studied under different soil water conditions. The dry matter accumulation in root was greatly influenced by water stress, so as to the final root weight of the treatment with 40% field moisture capacity(FMC) was less than 1/4 of that of the treatment with 80% FMC on average. Water stress during the 3-leaf stage to the tillering stage had the greatest influence on root, and the influence of water stress during the jointing stage to the booting stage on shoot was greater than root. However, water stress during the tillering stage to the booting stage had a balanced effect on root and shoot, and the proportion of dry matter that distributed to root and shoot was almost the same after rewatering. Water recovery during the jointing stage to booting stage could promote R/S, but the increasing degree was related to the duration of water limitation. Soil water condition had the lowest effect on R/S during the flowering stage to the filling stage and the maximal effect on R/S during the jointing stage to the heading stage, R/S of 40% FMC treatment was 20.93 and 126.09% higher than that of 60% FMC and 80% FMC treatments respectively at this period.
文摘Differential expression of gene in iron-efficient wheat cultivar Jing411 and iron-inefficient cul-tivar SanshumaiS under iron-deficiency and iron-sufficiency conditions was revealed by differential display reverse transcript PCR (DDRT-PCR) method. Northern blotting was carried out using ATP-binding transporter (ABC) cDNA obtained from DDRT-PCR products of the cultivar Jing411 as probe. Our results suggested that ABC gene expression was suppressed under iron-deficiency condition.
基金supported by the National Basic Research Program of China(973 Program,G1999011709)the Natural Science Foundation of Guangdong Province,China(33135).
文摘The equilibrium between root, shoot and growth stability under different soil water conditions were investigated in a tube experiment of winter wheat. The water supplying treatments included： sufficient irrigation at whole growth phase, moderate deficiency irrigation at whole growth phase, serious deficiency irrigation at whole growth phase, sufficient irrigation at jointing stage, tillering stage, flowering stage, and fillering respectively, after moderate and serious water deficit during their previous growth stage. Root and shoot biomass were measured. On the basis of the cooperative root-shoot interactions model, the equilibrium and growth stability were studied on the strength of the kinetics system theory. There was only one varying equilibrium point between the root and shoot over the life time of the winter wheat plant. Water stress prolonged the duration of stable growth, the more serious the water deficit, the longer the period of stable growth. The duration of stable growth was shortened and that of unstable growth was prolonged after water recovery. The growth behavior of the plants exposed to moderate water deficit shifted from stable to unstable until the end of the growth, after rewatering at flowering. In the life-time of the crop, the root and shoot had been adjusting themselves in structure and function so as to maintain an equilibrium, but could not achieve the equilibrium state for long. They were always in an unbalanced state from the beginning to the end of growth. This was the essence of root-shoot equilibrium. Water stress inhibited the function of root and shoot, reduced root shoot interactions, and as a result, the plant growth gradually tended to stabilize. Rewatering enhanced root shoot interactions, prolonged duration of instable growth. Rewatering at flowering could upset the inherent relativity during the long time of stable growth from flowering to filling stage, thus leading to unstable growth and enhanced dry matter accumulating rate in the whole plant.
基金the Ministry of Science and Technology of China （1999011700） the National Natural Science Foundation of China （49971042）.
文摘To reveal the period and after-effect of soil water stress on winter wheat, the article employs the experiment results carried out in the greenhouse. The results showed that the root-restricted weights varied with stress degrees and stress times during and after water stressing. In the course of stress, the chief reason resticting the weight of root was the stress intensity at this time, and that of severe stress treatment was larger than that of mild stress treatment. After water stress was relieved, the results of the after-effect of soil water stress on root growth were that, the stress intensity of short-time and mild stress was larger than that of long-time and severe stress. Comparing two-stage stress intensities, root-restricted weight resulted from after-effect intensity of stress under all of the short-time treatment, and the mild and the long-time stress treatments, while that resulted from the period stress intensity under the severe and the long-time stress treatments. In general, the effects of water stress on root were attributed to the three factors, a formed basis in the previous stage, the after-effect of water condition before this stage and influence of water in this stage, which lead to the characters of root in the whole growth stage.
文摘Effects of calcium on ATPase activities, lipid contents, and fatty acid compositions of plasma membrane from wheat roots were assayed under aluminum stress. The results showed that the increase of calcium concentration in the nutrient solution increased the activity of H + ATPase and the phospholipid content, decreased the activity of Ca 2+ ATPase and the galactolipid of plasma membrane. Owing to the decrease of linolenic acid content, the index of unsaturated fatty acid (IUFA) and index of double bond (DBI) decreased in Altas66. The IUFA and DBI of plasma membrane from Scout66 roots increased because its linolenic acid content increased obviously and its palmitic acid content decreased apparently.
基金Supported by Basic Science Fund from Beijing University of Agriculture(2016016004)Beijing Science and Technology New Stars Program(2008B22)"Strengthen Education with Trained Personnel Plan" for Beijing Municipal Colleges and Universities
文摘[ Objective ] This study aimed to investigate the regulatory role of potassium levels in plant gene expression. [ Method ] By using wheat （ Triticum aesti- vum L. Beinong 9549） as experimental material, the protein expression in wheat roots under different levels of potassium was determined by two-dimensional elec- trophoresis （2-DE）. [ Result] Compared with the plants supplied with normal level of potassium, 152 protein spots in wheat roots under potassium deficiency con- dition showed significant differences （P 〈 0.05 ）, including 76 protein spots significantly up-regulated by more than twice and 76 protein spots significantly down- regulated by more than twice. After potassium deficiency treatment, the wheat plants were supplied with normal level of potassium for two weeks, which showed sig- nificant differences in 73 protein spots compared with the plants continuously supplied with normal level of potassium （ P 〈 0. 05 ）, including 36 protein spots signif- icantly up-regulated by more than twice and 37 protein spots significantly down-regulated by more than twice. [ Conclusion] This study indicates that potassium de- ficiency stress would lead to induction of a large number of specific proteins in wheat roots.
基金Supported by the Key Programfromthe National Natural Science Foundation of China(30230230)the National Natural Science Foundation Agricultural Program of China(30070429)Scientific Research Program for Universities in Inner Mongolia Autonomous Region(NJZY07120)~~
文摘[Objective] The aim was to research the effect of concentration of NO-3-N on root vigor and rhizosphere pH of winter wheat seedlings under water culture.[Method]By selecting Hoagland's nutritional solution as cultural medium and winter wheat as material of experiment,on the basis,testing root vigor,nutrient solution NO-3 and change of pH values under the different level of disposal,such as high(containing NO-3-N 15 mmol/L),medium(containing NO-3-N 7.5 mmol/L)and lower(containing NO-3-N 2.5 mmol/L).[Result]The results of this research showed that the effect of different nitrogen level on the wastage of nutrient solution NO-3,the changes of pH values and root vigor is obvious under the hydroponics condition.[Conclusion]Though NO-3 is a safe nitrogen sources when it was supplied to plants too more,it would restrain assimilation on nitrate nitrogen farther,but when it was supplied to plants too little,it would lead to deficiency of NO-3 that plants uptake and decrease of root activity,so it isn't useful to wheat young seedling to absorb nitrogen nutrition.
基金supported by the National Natural Science Foundation of China (40701163)the Natural Science Foundation of Beijing City, China (6092019)+1 种基金the International Foundation for Science, Stockholm, Sweden, the Organization for the Prohibition of Chemical Weapons, the Hague, and the Netherlands, through a grant to Li Zhaojun (C/4076)the National Basic Research Program of China (973 Program, 2007CB109305)
文摘A solution culture experiment was performed to investigate the effects of oxytetracycline （OTC） on wheat （Triticum aestivum L.） growth, chlorophyll contents, and photosynthesis at five levels of 0, 10, 20, 40, and 80 mmol L-1 OTC. OTC is toxic to wheat. The wheat growth, especially wheat root was significantly decreased. Further OTC also significantly decreased root activity, chlorophyll contents, and photosynthetic parameters except for intercellular CO2 concentrations. The different responses of indicators such as root number, root activity and so on to OTC were also observed. The IC50 values for the tested indicators to OTC ranged from 7.1 to 113.4 mmol L-1 OTC. The order of indicator sensitivity to OTC was root number stomatal conductance chlorophyll a total chlorophyll photosynthetic rates total surface area transpiration rate chlorophyll b fresh weight of root dry weight of root total length dry weight of shoot = fresh weight of shoot total volume. The root number was more sensitive than other indicators with the IC50 value of 7.1 mmol L-1 OTC, and could be taken as the sensitive indicator to predict the hazards of OTC to wheat.
基金supported by the Fund of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,China(10501-1201)the Key Technologies R&D Program of China during the 11th Five-Year Plan period(2012BAD14B08)the Innovation Team Program,Ministry of Education of China
文摘Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals （nHRS）, drought tolerance and water use efficiency of winter wheat （Triticum aestivum）. The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots （1.06 and 0.94 mmol g-1 s-1, respectively）. The soil water content （SWC） at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants （61.1-44.6% field water capacity） than for intact root plants （57.9-46.1% field water capacity）. At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield （F PS II ）, the maximum photochemical efficiency of PS II （F v /F m ）, coefficient of photochemical quenching （qP）, and coefficient of non-photochemical quenching （NPQ）, in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency （WUE） than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought- resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.
文摘Effects of root penetration restriction on the growth and Mn nutrition of different wheat genotypes were studied in paddy soils using a method of nylon net bags (400 mesh) buried in the soil. The results showed that the spatial distribution of Mn in paddy soils played an important role in the growth and Mn nutrition of wheat crops. In the treatment where wheat roots were restricted in the plough layer by nylon net bags, the symptoms of Mn deficiency in wheat occurred much earlier and more seriously than usual. Of the two tested wheat genotypes, 80-8 was tolerant to Mn deficiency while 3295 was sensitive to Mn deficiency, respectively. The restriction of root penetration intensified symptoms of Mn deficiency of the Mn-deficient sensitive genotype (3295). The experiment demonstrated that well-developed roots with a strong ability to penetrate into the Mn-rich deep soil layer might explain the better tolerance of Mn deficiency in the tolerant genotypes.
基金funded by the Ph D Programs Foundation, Ministry of Education, China(20106202110002)the National Public Welfare Foundation for Industry Scheme of China (201103001)the National Natural Science Foundation of China (201131160265)
文摘Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was conducted from 2006 through 2008 in arid northwestern China to determine the effects of four tillage systems on soil properties, root development, water-use efficiency, and grain yield of winter wheat （Triticum aestivum L.）. The cultivar Fan 13 was grown under four tillage systems：conventional tillage （CT） without wheat stubble, no-tillage without wheat stubble mulching （NT）, no-tillage with wheat stubble standing （NTSS）, and no-tillage with wheat stubble mulching （NTS）. The soil bulk density （BD） under CT system increased gradually from sowing to harvest, but that in NT, NTSS, and NTS systems had little change. Compared to the CT system, the NTSS and NTS systems improved total soil water storage （0-150 cm） by 6.1-9.6 and 10.5- 15.3% before sowing, and by 2.2-8.9 and 13.0-15.1% after harvest, respectively. The NTSS and NTS systems also increased mean dry root weight density （DRWD） as compared to CT system. The NTS system significantly improved water-use efficiency by 17.2-17.5% and crop yield by 15.6-16.8%, and the NTSS system improved that by 7.8-9.6 and 7.0-12.8%, respectively, compared with the CT system. Our results suggested that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil bulk density, water storage, root system, and winter wheat yield.
文摘Root growth traits for different wheat types varied during the growth cycle. The root system of 93 Zhong 6, which is a dwarf, big-ear variety, reached its highest density at anthesis, while the root density of Zhoumai 13, a medium-type variety, demonsrated its highest value during the node elongation stage and decreased rapidly at later growth stages, which resulted in lower yield. The root density of Zhongyu 6 and 98 Zhong 18, high yield potential, multiple ears varieties, did not show observable variation in their root systems during their growth cycles.
文摘The object of the study was fungous diseases occurring on roots, leave sheaths and stem base of winter wheat in the two opposing cropping systems (organic and conventional). The observations were made in vegetation periods (2007-2009) in the fields of winter wheat in northern Poland. Every year on each plot of compared farming systems root rot occurred (Fusarium spp., Gaeumannomyces graminis and other fungi). For the period of 3 years the degree of disease injury on the roots of winter wheat grown in the conventional system in the vegetation period increased, while in the organic one remained on pretty the same level. On average a lot more affected roots, especially in the flowering stage, occurred on the winter wheat grown in the conventional system. Fusarium foot rot (Fusarium spp.) developed on the wheat during the entire vegetation period. It was the most dangerous root and foot rot disease (the highest indexes of injury). The mean degree of disease injury on leave sheath was on pretty the same level in the two farming systems, although in investigated vegetation periods differed a lot, whereas at the bases of stems the pathogen was on the higher level on the wheat in the conventional system. Also eyespot (Tapesia yallude) developed in the entire vegetation period of the winter wheat, but its intensity was much lower than in case of fusarium foot rot. Leave sheaths of the wheat grown in the conventional system were slightly stronger affected than those grown in the organic system. In the flowering stage the intensity of the disease in both farming systems became equal, while in the wax maturity it was considerably higher in the conventional system. Sharp eyespot (Rhizoctonia spp.) appeared relatively late and occurred only in two years of investigation. The intensiveness of the disease was definitely higher on the organic plots. Among the affected roots, taken in the stem elongation stage, from the organic system 28 cultures of fungi were isolated, and from the conventional one 24 colonies. Cereals pathogenic fungi amounted 35.8% of isolates obtained from the organic system and as many as 66.7% from the conventional system. Among the affected roots, taken in the flowering stage, from the organic system 68 cultures of fungi were isolated in all, and from the conventional one 25 colonies. Cereals pathogenic fungi amounted 38.2% of isolates obtained from the organic system and 56.0% from the conventional system. Among the affected stem bases, taken in the wax maturity stage, from the organic system 56 cultures of fungi were isolated in all, and from the conventional one 52 colonies. Cereals pathogenic fungi amounted 48.4% of isolates obtained from the organic system and 53.6% from the conventional system. In the case of all root and foot rot diseases of wheat grown in the organic system, an advantageous influence of greater biodiversity and number of various fungi species living in root proximity was noticed as opposed to the conventional system.
基金supported by the program for the New Century Excellent Talents in University of China (NCET-06-0819)the National Natural Science Foundation of China (30671272 & 30370882)+2 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of China (200458)the National High Technology Research and Development Program of China (863 Program,2006AA10Z179, 2006AA10Z1F8)the Scientific Research Fund of Sichuan Provincial Education Department, China.
文摘Aluminum （Al） toxicity often takes place in acidic soils with a pH of 5.5 or lower. Breeding and cultivation of Al tolerance wheat can partially protect wheat escaping from Al toxicity. The scarcity of the tolerant sources impedes the wheat breeding. In order to find new Al tolerance sources, we screened 173 bread wheat landraces from Tibet of China using hydroponic screening. It was indicated that： （1） There were diversities on the root regenerate length （RRL）. The RRL of a large of landraces were longer than 7.00 cm in pH 7 （58.38%） and pH 4.5 （66.47%）, but shorter than 5.00 cm in pH 4.5 ＋50μM Al^3＋ （80.93%）. The low pH showed either promotion or restraining effects depend on landraces, but Al toxicity under low pH only showed restraining effects on the root elongation. （2） There were also diversities on root tolerance index of low pH （RTI 1） or root aluminum tolerance index （RTI2） among cultivars. The RTI1 varied from a narrow range but with relatively high value （0.8722-1.2953） in comparison with that of RTI2 （0.3829-1.0058）, and the RTI1 of approximately 60% landraces was higher than 1.0000, the RTI2 of only 19.07% landraces was higher than 0.7000, suggesting that Al toxicity acted as an important factor for the reduction of the root elongation under acidic soils. （3） The RTI 1 of many wheats was higher than 1.0000, and As2256 and As2295 were the most tolerant for low pH, with RTI1 1.2953 and 1.2925, respectively. （4） Based on RTI2, seven wheats showed similar or higher tolerance to Al toxicity than Chinese Spring （CS）, a known tolerance wheat. Much better tolerance existed in landraces of As1543 and As1242, which can be used as the new parents for Al tolerant breeding.
基金supported by grants from the National Basic Research Program of China (973 Program, 2007CB109303)the National Natural Science Foundation of China (30871588 and 31000934)the Yangzhou University 'Crop Science' Project funded by the Priority Program of Jiangsu on Higher Education Institutions, China
文摘Plants need to be efficient in nutrient management, especially when they face the temporal nutrient defficiencies. Understanding how crops respond to nitrogen （N） starvation would help in the selection of crop cultivars more tolerant to N deficiency. In the present work, the physiological responses of two wheat cultivars, Yannong 19 （YN） and Qinmai 11 （QM）, to N starvation conditions were investigated. The two cultivars differed in biomass and N rearrangement between shoots and roots during N starvation. QM allocated more N to roots and exhibited higher root/shoot biomass ratio than YN. However, tissue measurement indicated that both cultivars had similar nitrate content in leaves and roots and similar remobilization rate in roots. Microelectrode measurement showed that vacuolar nitrate activity （concentration） in roots of QM was lower than that in roots of YN, especially in epidermal cells. Nitrate remobilization rates from root vacuoles of two cultivars were also identical. Moreover, vacuolar nitrate remobilization rate was proportional to vacuolar nitrate activity. During N starvation, nitrate reductase activity （NRA） was decreased but there were no significant differences between the two cultivars. Nitrate efflux from roots reduced after external N removal and QM seemed to have higher nitrate efflux rate.
