牛叠肚幼苗对盐胁迫的离子响应

以牛叠肚(Rubus crataegifolius)1 a生组培苗为试材,采用盆栽土培法研究不同浓度NaCl(0、30 mmol·L-1、60 mmol·L-1、90 mmol·L-1、120 mmol·L-1)处理对牛叠肚幼苗含水量及其体内Na+、K+、Ca2+吸收、运输与分配的影响。结果表明:NaCl胁迫浓度≤90 mmol·L-1范围内,牛叠肚幼苗含水量均高于对照,且维持在较稳定的水平,这将有利于减轻盐胁迫造成的生理干旱。NaCl胁迫处理下,牛叠肚幼苗根、茎、叶中Na+含量较对照显著增加,且茎中Na+含量显著高于根和叶;叶片中K+含量较对照显著降低,而Ca2+含量则较对照显著增加。随着胁迫浓度的升高,各器官中K+/Na+和Ca2+/Na+比值总体呈下降趋势,但叶片中K+/Na+、Ca2+/Na+始终保持相对较高比值,这对于维持叶片正常的生理功能具有重要意义。NaCl胁迫下,牛叠肚根向茎选择性运输Na+能力提高,而茎向叶选择性运输K+和Ca2+能力增强,茎中截留大量Na+,这有利于减缓盐胁迫对叶片和根系的伤害。该研究为深入了解牛叠肚盐碱适应机制提供了理论依据,同时也为牛叠肚的开发利用提供了一条新途径。     

无芒雀麦苗期耐盐指标筛选及耐盐性综合评价

采用温室模拟Na Cl盐胁迫试验方法,设置5种Na Cl浓度即0%(CK)、0.2%、0.4%、0.6%、0.8%,对5份无芒雀麦种质材料叶绿素含量(Chl)、相对电导率(REC)、超氧化物歧化酶活性(SOD)、丙二醛含量(Pro)等11项指标进行测定,对各单项指标的耐盐系数进行主成分分析、隶属函数法和逐步回归等方法进行无芒雀麦苗期耐盐性综合评价。结果表明:根据耐盐综合评价值D值得出材料耐盐性排序:ZXY05P-171>ZXY05P-604>ZXY05P-629>ZXY06P-2592>ZXY05P-735,筛选出叶绿素含量(Chl)、脯氨酸含量(Pro)、过氧化物酶活性(POD)、丙二醛含量(MDA)4个无芒雀麦苗期耐盐性评价指标;5份材料耐盐性预测回归模型:D=-4.344+6.158Chl+0.076Pro-1.591POD-0.129MDA,为无芒雀麦苗期耐盐种质材料评价及新品种选育提供科学理论依据。     

无菌培养条件下不同基因型小麦耐盐性及其生理机制研究

以4种不同基因型小麦(小偃6号、NR9405、RB6和陕229)种子为材料,研究组培条件下盐胁迫对小麦种子活力、幼苗生物量、保护酶活性、亲合性渗调物质以及Na+、K+ 含量等的影响.结果表明:盐胁迫下,小麦幼苗的生长均受到不同程度的抑制,表现为发芽率、根长、芽长、生物量随着盐浓度的升高而明显下降,并存在显著的基因型差异.盐胁迫下小偃6号与NR9405的生物量显著高于陕229与RB6;小偃6号与NR9405的超氧化物歧化酶(SOD )活性均随着盐浓度的增大而升高;RB6和陕229在0～150 mmol/L盐浓度下SOD酶活性升高,而在2 00 mmol/L盐浓度时,SOD活性急剧下降.随着盐浓度的升高4种不同基因型小麦体内游离脯氨酸累积量增大,在200 mmol/L时RB6的累积量显著高于其它基因型.随着盐浓度的升高,幼苗体内的Na+含量增加,K+含量下降,Na+/K+比值增大.小偃6号和NR9405的耐盐性优于陕229与RB6.     

Response of Main Osmotic Adjustment Substances to NaCI Stress Accumulation in Atriplex canescens

采用盆栽沙培方法,研究四翅滨藜主要渗透调节物质对NaCl浓度和盐胁迫时间的响应。结果表明：①胁迫时间对四翅滨藜叶片中脯氨酸、Na＋、K＋、Cl-含量和K＋/Na＋有极显著影响。随着胁迫时间的延长,叶中脯氨酸、Na＋含量增加,K＋含量、K＋/Na＋下降,Cl-含量变化趋势较复杂;NaCl胁迫〈40 d时,脯氨酸和Na＋含量增加幅度相对较小,〉40 d时均大幅增加。②NaCl浓度对四翅滨藜叶片中脯氨酸、Na＋、K＋、Cl-含量和K＋/Na＋也有极显著影响。随着NaCl浓度的增加,叶中脯氨酸、Na＋含量增加,K＋含量、K＋/Na＋下降;高NaCl浓度处理下,脯氨酸和Na＋含量增加幅度以及K＋含量、K＋/Na＋下降幅度均较大。③四翅滨藜体内离子运输具有选择性。盐胁迫下,根向茎选择运输K＋,将Na＋滞留在根部;茎向叶选择运输Na＋,抑制了K＋向叶片的运输,使从根部运输的K＋贮存在茎中;不同营养器官中K＋/Na＋从高到低依次为：茎〉叶〉根,并且都随着NaCl浓度的增加而降低。随着胁迫时间的延长,NaCl浓度对脯氨酸、K＋、Na＋及K＋/Na＋的影响逐渐放大,并且NaCl浓度与胁迫时间的交互作用也对以上指标（除K＋外）有极显著影响,因此在研究盐分浓度对植物盐胁迫的影响时,应考虑时间因素及盐分浓度与胁迫时间的交互作用。     

新疆尉犁县防护林带内四种杨树苗期耐盐性比较

在新疆尉犁县的防护林带内,乔木的主栽树种是4种杨树,包括中天杨(Populus×xiaozhuanica"Zhongtian")、新疆杨(Populus alba var.pyramidalis)、银新杨(Populus alba×Populus alba var.pyra-midalis)和胡杨(Populus euphratica)。文中选择叶片脯氨酸含量、K+/Na+、Cl-含量、SOD(超氧化物歧化酶)活性、MDA(丙二醛)含量和δ13C值等6个生理生态指标,对4种杨树苗期的耐盐性进行综合评价,为尉犁县建立耐盐型防护林选择适宜树种提供依据。研究的初步结论是中天杨和胡杨的耐盐性较强,所受的土壤盐胁迫较轻,表现在叶片MDA含量较低,δ13C值较高。但是二者的耐盐机理不同,中天杨主要通过提高叶片的Cl-含量和SOD活性耐盐,而胡杨主要通过增加叶片脯氨酸含量和K+/Na+来耐盐。     

盐胁迫下珍珠猪毛菜根茎叶矿质离子的吸收与分配响应

以珍珠猪毛菜[WTBX](Salsola passerina)[WTBZ]幼苗为材料,在不同盐浓度溶液中（0、100、200、300 mmol?L-1和400 mmol?L-1 NaCl）培养5 d和10 d,研究盐胁迫下珍珠猪毛菜幼苗根茎叶矿质离子的吸收与分配响应。结果表明:盐胁迫5 d和10 d后,随盐浓度增加,珍珠猪毛菜幼苗Na+含量降低,K+含量增加,叶片Na+含量低于根茎,叶片K+/Na+比值增大;盐胁迫10 d的茎叶中Cl-含量比胁迫5 d的趋于降低,Ca2+和Si4+含量趋于增加。通过分析K+和Na+在不同部位(根、茎、叶) 的运输选择性系数变化,发现珍珠猪毛菜的根与茎具有选择性运输K+,抑制Na+进入叶片的作用。     

水分胁迫下不同抗旱类型胡麻苗期生理生化指标变化

采用盆栽人工控水方法,研究了不同水分处理对苗期胡麻叶片相对含水量(RWC)、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性以及过氧化产物丙二醛(MDA)含量和游离脯氨酸(Pro)含量的影响。结果表明:在干旱胁迫下,不同抗旱类型的胡麻品种RWC均有不同程度的降低,在中度和重度胁迫下,RWC平均比CK降低4.36%和13.74%,即随胁迫强度的增加RWC下降幅度变大,强、弱抗旱性品种平均比CK降低7.67%和10.42%,即抗旱性强的品种RWC下降幅度相对较小;抗旱性强的品种其CAT和POD活性在中度和重度胁迫下平均比CK升高12.46%、15.14%和65.01%、156.01%,均随胁迫的增强而增加,但抗旱性弱的品种却为46.84%、29.85%和58.73%、38.20%,呈现先增后减的趋势;MDA含量均随胁迫加剧呈上升趋势,但抗旱性强的品种MDA含量随胁迫的增强增幅较小,为2.99%;Pro含量随水分胁迫程度的加剧不断增加,且抗旱性强的品种体内游离脯氨酸积累量较高,平均升高108.64%。RWC和Pro可作为胡麻苗期抗旱性鉴定的生理指标。     

NaCl和Na_2CO_3对枸杞的胁迫效应

对5个月苗龄的枸杞幼苗用0.3%～0.9%的中性盐NaCl和碱性盐Na2CO3处理,以观察枸杞幼苗对盐碱的耐受程度。结果表明:枸杞耐Na2CO3的最高浓度为0.3%,而耐NaCl的最高浓度为0.9%。在两种盐胁迫下,相对生长率、O2-·、H2O2、MDA含量以及质膜透性的变化趋势基本相似。但是,在Na2CO3胁迫下,相对生长率明显下降,O2-·、H2O2、MDA含量上升加剧,质膜透性也明显增加。叶绿素和可溶性蛋白含量明显下降;可溶性糖和淀粉含量出现明显下降趋势。而在NaCl胁迫下,叶片可溶性糖含量出现先降后升的趋势,根中的淀粉含量也出现缓慢上升的趋势,并且二者差异显著(P<0.05),由此说明枸杞对盐的耐受力高于碱。     

NaCl和Na2CO3对枸杞的胁迫效应

对5个月苗龄的枸杞幼苗用0.3%～0.9%的中性盐NaCl和碱性盐Na2CO3处理,以观察枸杞幼苗对盐碱的耐受程度.结果表明枸杞耐Na2CO3的最高浓度为0.3%,而耐NaCl的最高浓度为0.9%.在两种盐胁迫下,相对生长率、O2(-*)、 H2O2、 MDA含量以及质膜透性的变化趋势基本相似.但是,在Na2CO3胁迫下,相对生长率明显下降,O2(-*)、 H2O2、 MDA含量上升加剧,质膜透性也明显增加.叶绿素和可溶性蛋白含量明显下降;可溶性糖和淀粉含量出现明显下降趋势.而在NaCl胁迫下,叶片可溶性糖含量出现先降后升的趋势,根中的淀粉含量也出现缓慢上升的趋势,并且二者差异显著(P<0.05),由此说明枸杞对盐的耐受力高于碱.     

3种盐胁迫对玉米幼苗生长及叶片抗氧化酶和离子累积的影响

选取2个玉米品种(金玉819和金单999),探讨了3种盐胁迫(NaCl、Na_2SO_4和NaNO_3)对玉米幼苗生长、抗氧化酶活性以及叶片中K~+、Na~+、Ca~(2+)累积的影响。结果表明:3种不同类型的盐胁迫均会导致玉米幼苗鲜重下降,地上部鲜重金玉819下降超过28.6%,金单999下降超过18%;盐胁迫下金玉819叶片SOD酶活上升2.1倍以上, POD酶活性最高上升4.5倍,APX最高上升2.1倍,CAT最高上升2.2倍;金单999叶片SOD酶活最高上升2.1倍,APX最高上升1.6倍,CAT最高上升1.9倍。2个基因型玉米胁迫下叶片内Na~+含量上升4.5～6.3倍;NaCl和NaNO_3处理下,K~+/Na~+比对照降低90%～93%,而Na_2SO_4处理下K~+/Na~+下降78%～82%,金玉819和金单999的Ca~(2+)/Na~+比对照分别降低了85%～90%和92%～94%。综合分析表明NO~-_3引起的次生盐害对玉米生产危害较大。与金单999相比,金玉819对盐胁迫更加敏感,相同Na~+浓度处理下,金玉819的鲜重和SOD酶活性下降显著且拥有较低的K~+/Na~+和Ca~(2+)/Na~+值。     

Effects of spermidine and salinity stress on growth and biochemical response of paraquat‐susceptibe and ‐resistant goosegrass (Eleusine indica L.)

This study aimed to investigate the interaction effect of spermidine (Spd) and salinity stress on growth, photosynthetic rate, antioxidant system and free polyamines (PAs) contents of goosegrass (Eleusine indica L.) seedlings. E. indica was raised in a growth chamber under normal and toxic salt stress (100 mM of NaCl) and sprayed with 0 and 1.00 mM of Spd. The degree of growth inhibition caused by salt stress was lower in a paraquat‐resistant (R) biotype compared to a paraquat‐susceptible (S) biotype. Salt stress significantly elevated the accumulation of malondialdehyde, electrolyte leakage and proline and resulted in the degradation of chlorophyll; reduction in chlorophyll fluorescence; and a decrease in photosynthetic rate, relative water content and biomass. Spd‐treated plants maintained higher activities of antioxidant enzymes (catalase, superoxide dismutase and peroxidase), a greater rate of photosynthesis and lower osmotic pressure than untreated plants in the S biotype. Endogenous Spd content was reduced significantly in response to salt stress in both biotypes, but free PAs content in the S biotype was remarkably enhanced with exogenous Spd application under normal or salinity stress conditions. The result indicated that the S biotype was more sensitive to salinity than the R biotype; meanwhile, exogenous Spd maybe play an important role in protecting S biotype plants from salt stress.     

咸水灌溉对土壤水盐分布及设施番茄产量和品质的影响

为探明咸水灌溉对土壤水盐分布及设施番茄植株生长、产量和品质的影响,本试验以南疆地区设施番茄为研究对象,设置4个灌溉水矿化度,分别为2 g·L^-1（T1）、4 g·L^-1（T2）、6 g·L^-1（T3）和8 g·L^-1（T4）,并以淡水灌溉为对照（CK）,开展同一灌水定额条件下设施番茄适宜灌水矿化度的研究。结果表明：不同生育期阶段土壤含水率基本表现为20～60 cm土层较高,表层及深层土壤含水率相对较低,土壤含水率随着灌水矿化度的增大逐渐增加;0～80 cm土层平均土壤含水率在生育期内逐渐降低,且深层土壤降幅显著;生育期初始阶段土壤含盐量主要积聚在0～40 cm土层,随着生育期的推进土壤盐分呈累积趋势且向深层土壤运移,生育期末主要积聚在0～60 cm土层;灌水矿化度小于4 g·L^-1时0～20 cm土层整体呈脱盐状态,其中CK处理平均脱盐率达27.79%,T1处理平均脱盐率达17.07%;灌水矿化度2～4 g·L^-1促进了番茄植株生长,株高和茎粗相较CK分别...     

Comparison of the Salt Stress Tolerance of Promising Turkish Winter Squash (Cucurbita maxima Duch.) and Pumpkin (Cucurbita moschata Duch.) Lines and Interspecific Hybrids

The objective of this study was to evaluate several selected Cucurbita genotypes for their salt resistance in a rootstock breeding program for grafted watermelon seedling production. Specifically, changes in the relative water content (RWC), leaf area (LA), total chlorophyll content (TCC) and proline concentration (PC) of a commercial cultivar (G32 code), two promising winter squash (G12 and G13 of Cucurbita maxima Duch.) lines, six pumpkin (G3, G27, G28, G29, G30 and G31 of Cucurbita moschata Duch.) lines, and four C. maxima?×?C. mochata hybrids (G14, G15, G40 and G42), were investigated with a control treatment and four levels of salt stress (4, 8, 12 and 16?dS/m). In this study, Cucurbita cultivars which showed significant differences according to RWC, LA, TCC and PC at least significant difference (LSD) tests (P?<?0.05) and had salinity sensitivity index (SSI) value lower than 20%, were assessed as salt tolerant genotypes. The salt tolerant genotypes were grouped with principal component analysis (PCA) in each salt level. At the end of the study, all genotypes for all characteristics were generally tolerant at 4?dS/m salinity level. The G3, G12, G13, G14, G29 and G42 genotypes were resistant at 8?dS/m salinity, while the G15, G31, G32 and G40 were the most resistant genotypes at 12 and 16?dS/m. In conclusion, the selection of more salt resistant cultivars in rootstock breeding programs should be a priority to maintain growth performance in saline environments.

     

Application of SALTMED and HYDRUS-1D models for simulations of soil water content and soil salinity in controlled groundwater depth

Salinization is a gradual process that should be monitored. Modelling is a suitable alternative technique that saves time and cost for the field monitoring. But the performance of the models should be evaluated using the measured data. Therefore, the aim of this study was to evaluate and compare the SALTMED and HYDRUS-1 D models using the measured soil water content, soil salinity and wheat yield data under different levels of saline irrigation water and groundwater depth. The field experiment was conducted in 2013 and in this research three controlled groundwater depths, i.e., 60(CD60), 80(CD80) and 100(CD100) cm and two salinity levels of irrigation water, i.e., 4(EC4) and 8(EC8) d S/m were used in a complete randomized design with three replications. Soil water content and soil salinity were measured in soil profile and compared with the predicted values by the SALTMED and HYDRUS-1 D models. Calibrations of the SALTMED and HYDRUS-1 D models were carried out using the measured data under EC4-CD100 treatment and the data of the other treatments were used for validation. The statistical parameters including normalized root mean square error(NRMSE) and degree of agreement(d) showed that the values for predicting soil water content and soil salinity were more accurate in the HYDRUS-1 D model than in the SALTMED model. The NRMSE and d values of the HYDRUS-1 D model were 9.6% and 0.64 for the predicted soil water content and 6.2% and 0.98 for the predicted soil salinity, respectively. These indices of the SALTMED model were 10.6% and 0.81 for the predicted soil water content and 11.0% and 0.97 for the predicted soil salinity, respectively. According to the NRMSE and d values for the predicted wheat yield(9.8% and 0.91, respectively) and dry matter(2.9% and 0.99, respectively), we concluded that the SALTMED model predicted the wheat yield and dry matter accurately.     

不同矿化度的微咸水滴灌对红枣根区土壤碱解氮的影响

采用高矿化度的咸水与淡水按一定比例进行混合灌溉,分析不同矿化度的微咸水滴灌对枣树根区土壤碱解氮的影响模型。结果表明：当枣树根区土壤碱解氮的运移转化时间相同时,随着灌溉水矿化度的增加,土壤碱解氮的含量也随之增加,变化量越低,转化率越小。当矿化度相同时,土壤碱解氮平均值随运移转化时间先增大后减小,碱解氮的变化量呈递增趋势,而碱解氮变化率却呈现递减趋势。在分析不同矿化度的微咸水对土壤碱解氮影响的基础上,建立了微咸水的矿化度、碱解氮的运移转化时间与土壤碱解氮平均含量、变化量以及变化率之间的相互定量关系,并得到了相应的回归方程。     

间歇组合灌溉对中度盐化土壤水盐运移规律的影响研究

为了探究合理的微咸水农田灌溉模式,以中度盐化土壤为研究对象,在室内进行一维垂直积水入渗试验,研究不同咸淡水组合次序和间歇时间条件下土壤水盐运移规律,并对土壤盐分分布指标进行评价。结果表明:(1)间歇组合灌溉模式下各土层的土壤含水率均大于淡水直接灌溉,且与微咸水直接灌溉差异较小;先咸后淡土壤含水率变异系数介于9.24～16.62之间,相对于先淡后咸(11.54～20.88),土壤含水率分布更均匀。(2)在同一土层深度处,间歇组合灌溉模式下的土壤含盐量均小于微咸水直接灌溉,与淡水灌溉差异较小;在0～20 cm土层,先淡后咸土壤含盐量大于先咸后淡,而在20～55 cm土层,先咸后淡大于先淡后咸。(3)对土壤盐分评价指标进行分析表明,先咸后淡含盐量峰值大于先淡后咸;先淡后咸脱盐率平均值大于先咸后淡;在间歇组合灌溉模式下,脱盐区深度介于47.97～51.63 cm、达标脱盐区深度介于46.6～50.7之间,均超过了0～45 cm作物根系密度较大的土层;脱盐率平均值(0.36～0.543)、含盐量峰值(3.741～5.967)均高于微咸水直接灌溉,间歇组合灌溉更有利于为作物提供良好的生长环境。     

Combined effects of salinity and phosphorus availability on growth,gas exchange,and nutrient status of Catapodium rigidum

The combined effects of NaCl-salinity and phosphorus deficiency on biomass production, nutritional status, and photosynthetic activity were studied in Catapodium rigidum: an annual Poacea with fodder potential. Plants were grown in hydroponic conditions for 55 days under two phosphorus (P) supply: 5 (low) or 180?µmol KH₂PO₄ (sufficient), in the absence or presence of 100?mM NaCl. Obtained results demonstrated that both salinity and P deficiency treatments applied separately reduced substantially plant growth and CO₂ assimilation rate with a more marked impact of salt stress. Salinity has no substantial effect on both shoot P concentrations and phosphorus acquisition efficiency independently of P availability. The highest decrease in plant growth (?91%) was observed in plants simultaneously submitted to both stresses suggesting an additive effect of the two stresses and that P deficiency increased the susceptibility of C. rigidum to salinity. This may be linked to a significant decrease in potassium acquisition (?95%), K/Na selectivity ratio (?73%), stomatal conductance (?66%), CO₂ assimilation rate (?64%), and shoot water content (66%). Furthermore, plants cultivated under combined salinity and sufficient P supply displayed higher stomatal conductance, CO₂ assimilation rate, K/Na selectivity ratio, and plant growth than plants cultivated under combined effects of salinity and P deficiency. These results suggest that adding P to saline soils could be an alternative for alleviating the negative effects of salinity and may ameliorate salinity tolerance.     

Soil properties that determine the mortality and growth of Haloxylon aphyllum in the Aral region,Kazakhstan

Black saxaul (Haloxylon aphyllum) is a native tree species tolerant of aridity and salinity. It is planted to alleviate environmental damage due to the formation of the Aralkum desert and improve vegetation of the Aral Sea region. To investigate the environmental factors that determine seedling mortality and growth after rooting, we focused on soil properties and topographic factors in a study plot. We found that a hard clay layer that was low in hydraulic conductivity underlay accumulated sandy sediments at different depths. The soil in low seedling mortality areas was consistently sandy and low in salinity from the surface to a depth of 100 cm. In areas of high seedling mortality (75–100%), soils with a high content of silt and clay, with high salinity were detected within 100 cm depths. This suggests that accumulated sand sediment over a depth of 100 cm is required for root development. Plant height was positively correlated with depth of the hard clay layer. Significant relationships with plant height were also detected in chemical and physical properties at 80–100 cm such as electric conductivity (ECe), sodium adsorption ratio (SAR), and sand ratio. However, these properties had no significant relationship at 0–20 cm or with the relative elevation of the plot, suggesting that the subsequent growth of seedlings depends more on the sub-soil environment than on-surface conditions. The assessment of sub-soil condition is recommended to make site selection for reforestation much more reliable.     

土壤盐分对干旱区盐渍土壤碳垂直分布的影响

以新疆玛纳斯县盐渍土壤盐分和碳为研究对象,通过野外实地采样调查,分析干旱区盐渍土条件下的土壤盐分、有机碳、无机碳的垂直分布(0~300 cm)特征,探究土壤盐分对土壤碳垂直分布的影响。结果表明:土壤盐分含量随剖面深度增加呈"先增后降"的趋势,有机碳(SOC)含量随剖面深度增加呈下降趋势,无机碳(SIC)含量随剖面深度增加无明显变化规律。土壤剖面中,盐分与有机碳(SOC)含量及密度呈显著正相关(P0.05),在0~100cm土体中相关性最高(r=0.53);盐分与无机碳(SIC)含量及密度在整个土体中呈负相关关系,相关性不显著。     

干旱对高产小麦宁麦9号旗叶光合特性的影响

通过土壤自然干旱法,以共有一亲本但产量较低的宁麦8号为对照,研究了高产小麦宁麦9号旗叶光合特性。结果表明,土壤相对含水量RWCS、叶片相对含水量RWCL、净光合速率Pn、气孔导度gs、蒸腾速率E以及叶肉导度gm在整个自然干旱过程中不断降低;在干旱前8d,胞间CO2浓度Ci降低,水分利用效率WUE增加,而在干旱的8～12d,Ci增加,WUE降低。Pn与gm的变化呈显著的正相关(R2=0.938,P<0.0001),而与gs无明显的相关性。因此,在土壤干旱胁迫下,叶肉导度gm是抑制Pn的主导因素,而gs的影响较小。和宁麦8号相比,宁麦9号具有较高的Pn、gs、gm、WUE和较低的E。因此,较高的光合能力、水分利用效率以及较强的抗旱性可能是宁麦9号高产的生理基础,而其抗旱性强可归结为水分利用效率较高。