Starch Accumulation and Enzyme Activities Associated with Starch Synthesis in Maize Kernels

The filling rate and the starch accumulation in developing maize kernel were analyzed. The changes of enzyme activities associated with sucrose metabolism and starch biosynthesis were investigated. The purpose is to discuss the enzymatic mechanisms responsible for starch synthesis. Two types of maize cultivars （Zea mays）, high starch maize （Feiyu 3） and normal maize （Yuyu 22）, were grown in a corn field. The factors involved in starch synthesis were performed during the growth period. The kernel filling rate, the sucrose content, the starch accumulating rates and the activities of SS （sucrose synthase）, GBSS （granule-bound starch synthase）, SBE （starch branching enzyme） of Feiyu 3, which has high starch content, were significantly higher than those of Yuyu 22, which has low starch content, after 10 DAP （days after pollination）. Correlation analysis indicated that ADPGPPase （ADP-glucose pyrophosphorylase） and DBE （starch debranching enzyme） were not correlated with the starch accumulating rates and the kernel filling rate, but the SS activity at the middle and late period were highly significantly correlated with the starch accumulating rates and the kernel filling rate. The GBSS activity was highly significantly correlated with the amylose accumulating rate, but not correlated with the kernel filling rate. The SBE activity was highly significantly correlated with the amylopectin accumulating rate and the kernel filling rate. It was not ADPGPPase and DBE, but SS was the rate-limiting factor of starch biosynthesis in developing maize kernels. GBSS had an important effect on amylose accumulation, and SBE had a significant effect on amylopectin accumulation.     

Study on Accumulation Rule of Carbohydrates in Soybean （Glycine max（L.） Merrill）

Three soybean cultivars, Hefeng25 （HF25）, Suinongl4 （SN14） and Longxuanl （LX1） were used as materials and the accumulation features of carbohydrates were studied in leaves and stems. The results showed that the soluble sugar content in leaves and stems appeared the same trend of higher-lower-higher in three varieties. The changes of sucrose content in leaves appeared the same rule with that of soluble sugar, that is higher-lower-higher, while presented a rising trend in stems. The content of starch in leaves varied as a change of double apexes. The content of starch in stems appeared a change of single apex. In the same stage, there were some differences among carbohydrates. The content of soluble sugar and sucrose in SN14 was higher, and the starch content was lower.     

Accumulation of Carbohydrate and Regulation of 14-3-3 Protein on Sucrose Phosphate Synthase （SPS）Activity in Two Tomato Species

To explore the differences of carbohydrate metabolism in two tomato species and discuss the possible regulation of 14-3-3 proteins on the sucrose phosphate synthase （SPS） activity, we determined the contents of soluble sugar and starch through high performance liquid chromatography （HPLC）. The activities of sugar-metabolizing enzymes were assayed in desalted extract, and the relative expression levels of related genes in sugar metabolism were determined though real-time RT-PCR. The results indicated that glucose and fructose were mainly accumulated during the maturation of the fruit because of the high acid invertase （AI） and neutral invertase （NI） in Micro-Tom （Solanum lycopersicum） fruit, while in Solanum chmielewskii fruit, SPS which went along with the change of sucrose content led to the rapid sucrose increase during the fruit ripening. TFT1 and TFT10, belonging to 14-3-3 protein in tomato, were likely to down-regulated SPS activity during young and intumescence period.     

Effects of Increased Night Temperature on Cellulose Synthesis and the Activity of Sucrose Metabolism Enzymes in Cotton Fiber

Temperature is one of the key factors that influence cotton fiber synthesis at the late growth stage of cotton. In this paper, using two early-maturing cotton varieties as experimental materials, night temperature increase was stimulated in the field using far-infrared quartz tubes set in semi-mobile incubators and compared with the normal night temperatures (control) in order to investigate the effects of night temperature on the cotton fiber cellulose synthesis during secondary wall thickening. The results showed that the activity of sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) quickly increased and remained constant during the development of cotton fiber, while the activity of acid invertase (AI) and alkaline invertase (NI) decreased, increased night temperatures prompted the rapid transformation of sugar, and all the available sucrose fully converted into cellulose. With night temperature increasing treatment, an increase in SuSy activity and concentration of sucrose indicate more sucrose converted into UDPG (uridin diphosphate-glucose) during the early and late stages of cotton fiber development. Furthermore, SPS activity and the increased concentration of fructose accelerated fructose degradation and reduced the inhibition of fructose to SuSy; maintaining higher value of allocation proportion of invertase and sucrose during the early development stages of cotton fiber, which was propitious to supply a greater carbon source and energy for cellulose synthesis. Therefore, the minimum temperature in the nightime was a major factor correlated with the activity of sucrose metabolism enzymes in cotton fiber. Consequently, soluble sugar transformation and cellulose accumulation were closely associated with the minimum night temperature.     

Ameliorative Effects of Brassinosteroid on Excess Manganese-Induced Oxidative Stress in Zea mays L. Leaves

Manganese （Mn） is becoming an important factor limiting crop growth and yields especially on acid soils. The present study was designed to explore the hypothesis that brassinosteroid application can enhance the tolerance of maize （Zea mays L.） to Mn stress and if so, whether or not the mechanism underlying involves regulation of antioxidative metabolism in leaves. The effects of 24-epibrassinosteroid （EBR） on the growth, photosynthesis, water status, lipid peroxidation, accumulation of reactive oxygen species, and activities or contents of antioxidant defense system in maize plants under Mn stress were investigated by a pot experiment. At supplemented Mn concentrations of 150-750 mg kg^-1 soil, the growth of plants was inhibited in a concentration-dependent manner. The semi-lethal concentration was 550 mg Mn kgq soil. Foliage application with 0.1 mg L^-1 EBR significantly reduced the decrease in dry mass, chlorophyll content, photosynthetic rate, leaf water content, and water potential of plants grown in the soil spiked with 550 mg kg^-1 Mn. The oxidative stress caused by excess Mn, as reflected by the increase in malondialdehyde （MDA） content and lipoxygenase （LOX, EC 1.13.11.12） activity, accumulation of superoxide radical and H2O2, was greatly decreased by EBR treatment. Further investigations revealed that EBR application enhanced the activities of superoxide dismutase （SOD, EC 1.15.1.1）, peroxidase （POD, EC 1.11.1.7）, catalase （EC 1.11.1.6）, ascorbate peroxidase （APX, EC 1.11. 1.11）, dehydroascorbate reductase （DHAR, EC 1.8.5.1）, and glutathione reductase （GR, EC 1.6.4.2）, and the contents of reduced ascorbate and glutathione, compared with the plants without EBR treatment. It is concluded that the ameliorative effects of EBR on Mn toxicity are due to the upregulation of antioxidative capacity in maize under Mn stress.     

Effects of Exterior Abscisic Acid on Calcium Distribution of Mesophyll Cells and Calcium Concentration of Guard Cells in Maize Seedlings

In this study, the direct effects of exterior abscisic acid （ABA） on both calcium distribution of mesophyll cells and cytosolic calcium concentration of guard cells were examined. The distribution of Ca^2＋ localization were observed with calcium antimonate precipitate-electromicroscopic-cyto-chemical methods after treated with ABA and pretreated with ethylene glycol-bis-（2-aminoethylether）-N,N,N＇,N＇-tetraacetic acid （EGTA）, verapamil （Vp）, and trifluoperazine （TFP）. The laser scanning confocal microscopy was used to measure the cytosolic calcium concentrations of guard cells under different treatments. The results showed that the cytosolic Ca^2＋ concentration of mesophyll ceils was induced to increase by ABA, but to decrease in both outside cell and the vacuoles within 10 rain after treatments. The cytosolic calcium concentration of guard cells was increased gradually with the lag in treatment time. However, both EGTA and TFP could inverse those effects, indicating that the increase of cytosolic calcium induced by exterior ABA was mainly caused by calcium influx. The results also showed that calmodulin could influence both the calcium distribution of mesophyll cells and calcium concentration of guard cells. It shows that calmodulin participates in the process of ABA signal transduction, but the mechanism is not known as yet. The changes both calcium distribution of mesophyll cells and calcium concentration of guard cells further proved that the variations of cytosolic Ca^2＋ concentration induced by ABA were involved in the stomatal movements of maize seedlings.     

Effects of chilling tolerance induced by spermidine pretreatment on antioxidative activity,endogenous hormones and ultrastructure of indica-japonica hybrid rice seedlings

Spermidine(Spd) is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions.Antioxidant activities,endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings.12-d-old seedlings were subjected to exogenous Spd(1 mmol L~(-1)) and then a chilling stress(6℃,4 d) was induced,followed by a subsequent recovery(25℃,4 d).Results showed that malondialdehyde(MDA) and proline content were enhanced significantly,whereas shoot fresh and dry weights decreased during chilling stress and after recovery;chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery;additionally,total soluble sugar,sucrose,fructose and starch contents increased significantly during chilling stress,and only soluble sugar and fructose contents were observed in increase after recovery;chilling stress-induced increases in superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) activities,but declined after recovery,and the level of ascorbate peroxidase was lower during chilling stress and after recovery;however,endogenous indole-3-acetic acid(IAA),zeatin riboside(ZR),gibberellic acid(GA_3),and abscisic acid(ABA) levels were induced decreased compared with Spd pretreatment.The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery.In contrast,exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde,proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism.After recovery,Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts.These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.     

An Analysis to the Driving Forces for Water and Salt Absorption in Roots of Maize Seedlings Under Salt Stress

When maize seedlings were subjected to salt stress,a decline in root xylem pressure was observed within seconds,followed by a gradual increase in Na＋ deposition in the seedlings.The magnitude of xylem pressure response was positively correlated with,but not proportional to the intensity of the stress.A continuous recording of the xylem pressure profile showed that self-regulation of the xylem pressure existed before and after the imposition of salt stress when the environmental conditions were relatively stable.The salt induced increase in xylem tension dominated the total water potential of the plant when the salt stress was mild,but the osmotic potential became more prominent when the NaCl concentration in the root bathing solution was raised to over 100 mol m-3.The average transpiration rate of the seedlings dropped by 40% when the NaCl concentration in the root ambient was increased to 150 mol m-3.Although salt stress resulted in the decline of both the xylem pressure potential and the osmotic potential in the root xylem,the changes in the total water potential of the root xylem solution were always smaller than the changes in the water （osmotic） potentials of the solution bathing the root.An analysis to the water relations of maize seedlings showed that not only the water potential components,but the radial reflection coefficient of the roots was also dependent on the level of salinity.When the NaCl level in the root bathing solution was raised from 25 to 150 mol m-3,the radial reflection coefficient of the root declined from 0.43 to 0.31.This small change resulted in a remarkable increase in the normalised relative NaCl absorption by 2.4 times,indicating that the radial reflection coefficient of root played a very important role in regulating the absorption of NaCl in maize seedlings under salt stress.     

Study on the Change of GAs,ABA Level and ABA／GAs Ratio in the Embryos of Spring Wheat and Winter Wheat During Vernalization

Spring wheat(cv.7742)and winter wheat (cv.Nongda 015) were vernalized by seed chilling,and the changes of GAs,ABA content and GAs/ABA ration in embryo wer investigated.The differences between cultivars,treatments and variety-treatment inleractions were significant for both GAs and ABA.The level of GAs and ABA as well as GAs/ABA ratio were hardly changed by seed chilling in spriug wheat Howerve,in winter wheat,the GAs content decreased much less compared with ABA that reduced sharply after chilling.It showed that the GAs/ABA ratio in winter wheat was increased remarkably(4.55 times)than in spring wheat.It was suggested that the absolute GAs Ievel was independent of the vernalization effect because there was a higher GAs Level before and after seed chilling in winter wheat when compared with spring wheat,One of the vemalization effects was the decline of ABA level that led to the increase of GAs/ABA ratio.     

水分胁迫对桃叶片碳水化合物及其相关酶活性的影响

以 2年生盆栽 庆丰"桃为试材,在早春进行干旱处理,研究水分胁迫下桃叶碳水化合物的浓度及其相关酶活性的变化。结果表明:山梨醇和葡萄糖是桃叶中起渗透调节的主要物质。随着胁迫程度的增加,桃叶中山梨醇、葡萄糖、果糖浓度显著增加,淀粉和蔗糖浓度显著降低。桃叶中 6 磷酸醛糖还原酶、山梨醇脱氢酶、磷酸蔗糖合成酶、中性转化酶、淀粉酶活性均显著升高,酸性转化酶活性变化平稳     

Causes of Poor Grain Plumpness of Two-Line Hybrids and Their Relationships to the Contents of Hormones in the Rice Grain

This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations,that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), and abscisic acid (ABA), the ethylene evolution rate, activities of sucrose synthase (SuSase) and starch synthase (StSase) in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z + ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z + ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and gram weight.The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight.Spraying ethephon (ethylene-releasing agent) at the early grain filling stage increased the evolution rate of ethylene,reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight.The results were reversed when cobatous nitrate (an inhibitor of ethylene synthesis) was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z + ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents.     

藁城8901和山农1391淀粉合成酶活性和淀粉组分积累特征的比较

 选用藁城8901（强筋）和山农1391（弱筋）两个小麦品种，比较研究了其小麦蔗糖代谢、淀粉合成相关酶活性的变化及淀粉组分的积累特征。结果表明，蔗糖合成酶（SS）、磷酸蔗糖合成酶（SPS）、腺苷二磷酸葡萄糖焦磷酸化酶（ADPGPPase）、可溶性淀粉合成酶（SSS）活性以及蔗糖积累量的高低均存在明显的基因型差异，淀粉积累量较高的弱筋品种山农1391显著高于淀粉积累量较低的强筋品种藁城8901。而结合态淀粉合成酶（GBSS）活性与两品种籽粒直链淀粉积累量的变化情况相吻合，小麦籽粒灌浆中后期的GBSS活性对直链淀粉终积累量的调节作用大于籽粒灌浆前期。用Richards方程模拟籽粒直链淀粉和支链淀粉的积累过程发现，直链淀粉和支链淀粉终积累量的高低取决于其积累启动时间的早晚和前期积累速率的高低，而不是积累持续期的长短。通过比较两品种蔗糖转化量、淀粉积累速率与蔗糖和淀粉代谢相关酶活性的变化趋势可以看出，蔗糖转化量与SSS和GBSS的变化趋势一致；淀粉积累速率与ADPGPPase活性和SS/SPS活性比率的变化趋势一致，而与SS 、SPS、SSS或GBSS活性的变化并不吻合，说明籽粒中淀粉积累速率及其组分积累量的高低与SS、SPS、SSS和GBSS单个酶活性的高低并不存在必然联系，而与ADPGPPase活性和籽粒中蔗糖合成与降解的平衡密切相关。     

不同外源激素对香草兰花芽分化的影响

为探究香草兰花芽分化调控措施及相关机理,在花芽分化前期,以分别喷施细胞分裂素(6-BA)、脱落酸(ABA)、生长素(IAA)和赤霉素(GA)为处理,以清水为对照,分析各处理条件下功能叶内源激素和营养物质含量变化,并统计各处理对花芽分化率的影响。结果表明:6-BA和ABA处理均能增加功能叶中玉米素核苷(ZR)和ABA含量,提高其在花芽分化过程中的蛋白质、可溶性糖和淀粉含量;IAA处理能提高花芽分化中后期功能叶IAA、ABA、ZR和GA含量,却降低整个分化过程中蛋白质、可溶性糖和淀粉的含量;GA处理降低了ZR和ABA含量,对蛋白质和淀粉含量影响不大;除GA处理外,6-BA、ABA、IAA处理均在一定程度上提高了花芽分化率,以6-BA最为显著,可参考在生产上施用。     

Effect of polyamine on seed germination of wheat under drought stress is related to changes in hormones and carbohydrates

Drought is a multifaceted stress condition that inhibits crop growth. Seed germination is one of the critical and sensitive stages of plants, and its process is inhibited or even entirely prevented by drought. Polyamines(PAs) are closely associated with plant resistance to drought stress and seed germination. However, little is known about the effect of PA on the seed germination of wheat under drought stress. This study investigated the involvement of PAs in regulating wheat seed germination under drought stress. Six wheat genotypes differing in drought resistance were used, and endogenous PA levels were measured during seed germination under different water treatments. In addition, external PA was used for seed soaking and the variation of hormones, total soluble sugar and starch were measured during the seed germination under different water treatments. These results indicated that the free spermidine(Spd) accumulation in seeds during the seed germination period favored wheat seed germination under drought stress; however, the free putrescine(Put) accumulation in seeds during the seed germination period may work against wheat seed germination under drought stress. In addition, seed soaking in Spd and spermine(Spm) significantly relieved the inhibition of seed germination by drought stress; however, soaking seeds in Put had no significant effect on seed germination under drought. External Spd and Spm significantly increased the endogenous indole-3-acetic acid(IAA), zeatin(Z)+zeatin riboside(ZR), abscisic acid(ABA), and gibberellins(GA) contents in seeds and accelerated the seed starch degradation and increased the concentration of soluble sugars in seeds during seed germination. This may promote wheat seed germination under drought stress. In conclusion, free Spd and Put are key factors for regulating wheat seed germination under drought stress and the effects of Spd and Put on seed germination under drought notably related to hormones and starch metabolism.     

不同栽培方法对苦荞内源激素及产量和品质的影响

为探明不同苦荞品种成熟期内源激素含量的差异及其与苦荞产量和品质的关系,以四川本地4种苦荞品种西荞1号、米荞1号、川荞1号和川荞2号为试验材料,对比2种栽培方法下4种苦荞的内源激素含量、产量和营养品质;测定其在常规栽培方法和新型栽培技术(发明专利申请号201610057193.3,公开号105660133A)下苦荞的单株粒重、千粒重、产量、膳食纤维、蛋白质、黄酮和淀粉的含量,以及其成熟期茎、叶、根中脱落酸(ABA)、玉米素+玉米素核苷、生长素(IAA)、1-氨基环丙烷-1-羧酸(ACC)和多胺(腐胺、亚精胺、精胺)等内源激素的含量,并进行相关性分析。结果显示,4种苦荞的膳食纤维、蛋白质、黄酮及淀粉含量与苦荞叶中的ABA含量呈显著负相关;蛋白质含量与叶、根中的玉米素+玉米素核苷及IAA含量呈显著或极显著正相关;黄酮含量与叶中的IAA、ACC和多胺的含量呈显著或极显著正相关。表明苦荞的产量和品质与其不同部位间的内源激素含量有密切关系,并且可以通过新型栽培技术调节其内源激素含量,以达到改善苦荞品质和产量的目的。     

两系杂交稻籽粒充实不良的成因及其与激素含量的关系

 【目的】阐明两系杂交稻籽粒充实特征及籽粒充实不良的成因与激素机理。【方法】采用结实特性差异明显的两系杂交稻为材料，测定籽粒中蔗糖和淀粉含量、玉米素+玉米素核苷（Z+ZR）、吲哚-3-乙酸（IAA）和脱落酸（ABA）含量、乙烯释放速率、蔗糖合成酶（SuSase）和淀粉合成酶（StSase）活性以及籽粒灌浆充实指标，并进行相关分析。【结果】表明两系杂交稻结实率低，主要归咎于弱势粒的秕粒率高、充实度差。籽粒充实度差的组合，灌浆前、中期弱势粒中蔗糖含量高于强势粒，表明基质浓度不是两系杂交稻弱势粒灌浆速率慢和籽粒充实度差的主要限制因子。灌浆前期强势粒中的Z+ZR、IAA和ABA含量明显高于弱势粒，Z+ZR、IAA和ABA的最高含量和平均含量与籽粒最大灌浆速率、平均灌浆速率、谷粒充实度和粒重均呈极显著的正相关。灌浆前、中期弱势粒中的乙烯释放速率明显高于强势粒，籽粒充实度差的组合高于籽粒充实度好的组合，乙烯的释放速率与灌浆速率、谷粒充实度和粒重均呈极显著的负相关。在灌浆初期喷施乙烯合成促进剂（乙烯利），弱势粒的乙烯释放速率增加，ABA含量减少，SuSase和StSase活性降低，谷粒充实度和粒重下降；喷施乙烯合成的抑制剂（硝酸钴），结果则相反。表明籽粒中激素含量及其平衡对籽粒灌浆和酶的活性起调控作用，部分两系杂交稻籽粒充实不良与其弱势粒中Z+ZR、IAA和ABA含量低、乙烯浓度高有密切关系。【结论】激素对两系杂交稻籽粒充实起重要作用，通过调控激素含量，可以提高籽粒充实。     

TDZ和6-BA对芜菁离体再生过程中内源激素水平的不同影响(英文)

为研究外源TDZ和6-BA对芜菁离体再生过程中内源激素的影响来阐明TDZ在促进芜菁离体再生方面比6-BA更为有效的原因,采用不同浓度的TDZ和6-BA分别配合不同浓度NAA诱导芜菁带柄子叶离体再生.结果表明:适合芜菁带柄子叶离体再生的外源激素浓度组合分别是TDZ 4·0 mg·L-1+ NAA1·0 mg·L-1和6-BA5·0 mg·L-1+ NAA1·0 mg·L-1;在这2种组合诱导下的不定芽再生率分别是80·4 %和30·2 %.分别测定在这2种外源激素组合诱导下带柄子叶外植体内源生长素(IAA)、玉米素(Z)、赤霉素(GAs)和脱落酸( ABA)的绝对含量,并计算IAA/ABA和IAA/Z之间的相对含量.结果表明:TDZ 4·0 mg·L-1+ NAA1·0 mg·L-1的激素组合诱导带柄子叶外植体产生内源IAA和Z的水平峰值显著高于6-BA5·0 mg·L-1+ NAA1·0 mg·L-1的激素组合;而在2种外源激素组合诱导条件下,内源GAs和ABA的含量差异不显著;IAA的绝对含量左右了IAA/ABA和IAA/Z的变化趋势.综合内源激素的绝对含量和相对含量,TDZ比6-BA更好地诱导芜菁分化效果的关键因素是由于TDZ诱导外植体产生了更高水平的IAA含量和IAA/ABA比值.TDZ和6-BA诱导产生不同水平的内源Z和IAA/Z的作用还不明确.     

水分胁迫对寒富苹果叶片碳氮代谢的影响

以盆栽"寒富"苹果为试材,研究了不同水分胁迫处理对"寒富"苹果碳氮代谢的影响。结果表明:水分胁迫使"寒富"苹果叶片内可溶性糖、游离氨基酸和可溶性蛋白含量升高,淀粉含量降低,胁迫越严重,变化幅度越大。轻度干旱胁迫提高了"寒富"苹果叶片中性转化酶、酸性转化酶和蔗糖合成酶活性,降低了蔗糖磷酸合成酶、山梨醇脱氢酶、山梨醇氧化酶、硝酸还原酶、亚硝酸还原酶、谷丙转氨酶、谷草转氨酶和谷氨酰胺合成酶的活性;中度、重度干旱胁迫和淹水条件下,中性转化酶、酸性转化酶和蔗糖合成酶降低,蛋白酶活性增加。"寒富"苹果能忍耐轻度和中度干旱胁迫,抗旱性较强。