Effects of sodium on nitrate uptake and osmotic adjustment of Suaeda physophora

Na+ ions play an important role in the growth of halophyte. The effect of Na+ ions on nitrate uptake and osmotic adjustment in the euhalophyte Suaeda physophora was investigated under glasshouse conditions. Seedlings were exposed to 1 mmol/L NaCl (control),300 mmol/L NaCl,150 mmol/L NaCl plus 150 mmol/L KCl or 300 mmol/L KCl treatments for 24 d. Dry weight was not affected greatly by different salt treatments,but water content and succulence in leaves of S. physophora were significantly increased at 300 mmol/L NaCl and 150 mmol/L NaCl plus 150 mmol/L KCl treatments. The concentrations of Na+ and NO3’ in leaves of S. physophora were the highest at 150 mmol/L NaCl plus 150 mmol/L KCl,but lowest at 300 mmol/L KCl treatment. Moreover,the increase of NO3’ concentration did not result in the decrease of Cl-concentration at 150 mmol/L NaCl plus 150 mmol/L KCl treatments. The estimated contribution of NO3’ to osmotic potential (CNO3) in leaves of S. physophora was 9.8% at 150 mmol/L NaCl plus 150 mmol/L KCl,and CNa and CCl were 31.0% and 23.3%,respectively. However,CNO3,CNa and CCl were respectively 1.6%,7.9% and 11.9% at 300 mmol/L KCl treatment. It is concluded that Na+ stimulates NO3’ absorption and the stimulation is independent on the internal or the external Cl-concentration in the euhalophyte S. physo-phora. These characteristics may explain the high levels of N in leaves of saline desert plants in arid ecosystem.     

外源茉莉酸和真菌激发子诱导白菜CaMBP10的表达

 Recently,CaMBP10 was identified as a plant lipid transfer protein(LTP).In the study,four leaves old cabbages were treated with exogenous jasmonic acid(JA),JA plus LTP,fungal elicitor,200 mmol/L NaCl and 20% PEG respectively for understanding the functions of CaMBP10 in vivo.The expression of CaMBP10 was determined by using semi-quantitative RT-PCR.The results showed that the expressions of CaMBP10 were dramatically up-regulated in different levels under indicated conditions.It demonstrated that CaMBP10 was involved in biotic and abiotic stress response.     

Growth and physiological responses of Agriophyllum squarrosum to sand burial stress

Agriophyllum squarrosum is an annual desert plant widely distributed on mobile and semi-mobile dunes in all the sandy deserts of China. We studied the growth and physiological properties of A. squarrosum seedlings under different sand burial depths in 2010 and 2011 at Horqin Sandy Land, Inner Mongolia to understand the ability and mechanism that A. squarrosum withstands sand burial. The results showed that A. squarrosum had a strong ability to withstand sand burial. Its survival rate, plant height and biomass increased significantly at a burial depth 25% of seedling height and decreased significantly only when the burial depth exceeded the height of the seedlings; some plants still survived even if the burial depth reached 266% of a seedling height. The malondialdehyde(MDA) content and membrane permeability of the plant did not change significantly as long as the burial depth was not greater than the seedling height; lipid peroxidation increased and cell membranes were damaged if the burial depth was increased further. When subjected to sand burial stress, superoxide dismutase(SOD) and peroxidase(POD) activities and free proline content increased in the seedlings, while the catalase(CAT) activity and soluble sugar content decreased. Sand burial did not lead to water stress. Reductions in photosynthetic area and cell membrane damage caused by sand burial may be the major mechanisms increasing mortality and inhibiting growth of the seedling. But the increases in SOD and POD activities and proline content must play a certain role in reducing sand burial damage.     

Variation of soil physical-chemical characteristics in salt-affected soil in the Qarhan Salt Lake,Qaidam Basin

Soil salinization has adverse effects on the soil physical-chemical characteristics.However,little is known about the changes in soil salt ion concentrations and other soil physical-chemical characteristics within the Qarhan Salt Lake and at different soil depths in the surrounding areas.Here,we selected five sampling sites(S1,S2,S3,S4,and S5)alongside the Qarhan Salt Lake and in the Xidatan segment of the Kunlun Mountains to investigate the relationship among soil salt ion concentrations,soil physical-chemical characteristics,and environmental variables in April 2019.The results indicated that most sites had strongly saline and very strongly saline conditions.The main salt ions present in the soil were Na⁺,K⁺,and Cl^-.Soil nutrients and soil microbial biomass(SMB)were significantly affected by the salinity(P<0.05).Moreover,soil salt ions(Na⁺,K⁺,Ca2+,Mg²⁺,Cl^-,CO₃^2-,SO₄^2-,and HCO₃^-)were positively correlated with electrical conductivity(EC)and soil water content(SWC),but negatively related to altitude and soil depth.Unlike soil salt ions,soil nutrients and SMB were positively correlated with altitude,but negatively related to EC and SWC.Moreover,soil nutrients and SMB were negatively correlated with soil salt ions.In conclusion,soil nutrients and SMB were mainly influenced by salinity,and were related to altitude,soil depth,and SWC in the areas from the Qarhan Salt Lake to the Xidatan segment.These results imply that the soil quality(mainly evaluated by soil physical-chemical characteristics)is mainly influenced by soil salt ions in the areas surrounding the Qarhan Salt Lake.Our results provide an accurate prediction of how the soil salt ions,soil nutrients,and SMB respond to the changes along a salt gradient.The underlying mechanisms controlling the soil salt ion distribution,soil nutrients,and SMB in an extremely arid desert climate playa should be studied in greater detail in the future.     

Effects of climate change and land use/cover change on the volume of the Qinghai Lake in China

Qinghai Lake is the largest saline lake in China.The change in the lake volume is an indicator of the variation in water resources and their response to climate change on the Qinghai-Tibetan Plateau(QTP)in China.The present study quantitatively evaluated the effects of climate change and land use/cover change(LUCC)on the lake volume of the Qinghai Lake in China from 1958 to 2018,which is crucial for water resources management in the Qinghai Lake Basin.To explore the effects of climate change and LUCC on the Qinghai Lake volume,we analyzed the lake level observation data and multi-period land use/land cover(LULC)data by using an improved lake volume estimation method and Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.Our results showed that the lake level decreased at the rate of 0.08 m/a from 1958 to 2004 and increased at the rate of 0.16 m/a from 2004 to 2018.The lake volume decreased by 105.40×10⁸ m³ from 1958 to 2004,with the rate of 2.24×10⁸ m³/a,whereas it increased by 74.02×10⁸ m³ from 2004 to 2018,with the rate of 4.66×10⁸ m³/a.Further,the climate of the Qinghai Lake Basin changed from warm-dry to warm-humid.From 1958 to 2018,the increase in precipitation and the decrease in evaporation controlled the change of the lake volume,which were the main climatic factors affecting the lake volume change.From 1977 to 2018,the measured water yield showed an"increase-decrease-increase"fluctuation in the Qinghai Lake Basin.The effects of climate change and LUCC on the measured water yield were obviously different.From 1977 to 2018,the contribution rate of LUCC was -0.76% and that of climate change was 100.76%;the corresponding rates were 8.57% and 91.43% from 1977 to 2004,respectively,and -4.25% and 104.25% from 2004 to 2018,respectively.Quantitative analysis of the effects and contribution rates of climate change and LUCC on the Qinghai Lake volume revealed the scientific significance of climate change and LUCC,as well as their individual and combined effects in the Qinghai Lake Basin and on the QTP.This study can contribute to the water resources management and regional sustainable development of the Qinghai Lake Basin.     

Response of stomatal conductance of two tree species to vapor pressure deficit in three climate zones

Stomatal behavior is a central topic of plant ecophysiological research under global environmental change. However, the physiological mechanism controlling the response of stomata to vapor pressure deficit(VPD) or relative humidity(RH) has been inadequately understood till now. In this study, responses of stomatal conductance(gs) to VPD in two species of trees(Fraxinus chinensis Roxb., Populus alba L. var. pyramidalis Bge.) in three different climate zones(Jinan with typical warm humid/semi-humid climate, Urumqi with temperate continental arid climate and Turpan with extreme arid desert climate) were measured. Levels of two phytohormones(abscisic acid, ABA; indole-3-acetic acid, IAA) in the leaves of the two tree species at these three sites were also measured by high performance liquid chromatography. The results showed that the responses of gs to an increasing VPD in these two tree species at the three sites had peak curves which could be fitted with a Log Normal Model(gs=a·exp(–0.5(ln(D/c)/b)2). The VPD/RH values corresponding to the maximum gs can be calculated using the fitting models for the two tree species in the three sites. We found that the calculated gs-max-VPD correlated negatively with relative air humidity in the three sites during the plant growth period(April to October 2010), which showed the values of gs-max-VPD were related to the climate conditions. The prevailing empirical stomatal model(Leuning model) and optimal stomatal behavior model could not properly simulate our measured data. The water use efficiency in the two tree species did not show obvious differences under three very different climatic conditions, but the highest gs, photosynthetic and transpiration rates occurred in P. alba var. of Turpan. The sensitivity in response of gs to VPD in leaves of the two trees showed positive correlations with the concentration of ABA, which implied that ABA level could be used as an indicator of the sensitivity of stomatal response to VPD. Our results confirmed that the prediction of the response of gs to VPD might be incomplete in the two current popular models. Therefore, an improved gs model which is able to integrate the results is needed. Also, the stomatal response mechanism of single peak curves of gs to VPD should be considered.     

Heterosis for water uptake by maize (Zea mays L.) roots under water deficit: responses at cellular,single-root and whole-root system levels

To examine the potential heterosis for water uptake by maize roots, the hydraulic properties of roots in the F1 hybrid (Hudan 4) were compared with those of its inbred parents (♂ 478 and ♀ Tian 4) at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions. The cell hydraulic conductivity (Lpc) decreased under water deficit, but the Lp c of the F1 was higher than that of its inbred parents with or without stress from water deficit. Marked reductions in Lp c were observed following Hg2+ treatment. The hydrostatic hydraulic conductivity of single roots (hydrostatic Lp sr ) varied among genotypes under the two water treatments, with the highest in the F1 and the lowest in ♂ 478. Radial hydraulic conductivity (radial Lpsr ) and axial hydraulic conductance (Lax ) of the three genotypes varied similarly as Lpsr . The variations in hydraulic parameters were related to root anatomy. Radial Lp sr was negatively correlated with the ratio of cortex width to root diameter (R2=-0.77, P<0.01), whereas L ax was positively correlated with the diameter of the central xylem vessel (R2 =0.75, P<0.01) and the cross-sectional area of xylem vessels (R2 =0.93, P<0.01). Hydraulic conductivity (Lpwr ) and conductance (Lwr ) of the whole-root system followed the same trend under the two water treatments, with the highest values in the F1 . The results demonstrated that heterosis for water uptake by roots of the F1 occurred at cellular, single-root and whole-root system levels under well-watered and water-deficit conditions.     

稻瘟病菌激发子诱导非寄主植物的抗病效果

 Hyphal cell wall crude elicitor(CWE)of rice blast pathogen could induce hypersensitive response in tobacco and induce other nonhost plants to be resistant to other fungal pathogens.When corn was treated with CWE,they inhibited the infection of Exserohilum turcicum and Curvularia lunata,and when plants of capsicum and cucumber were treated with CWE,they inhibited the infection of Colletotrichum gloeospori-oides.CWE solution showed no bioactivity on spore germination and hyphal growth of the experiment fungi in vitro.Nonhost resistance induced by CWE to other fungal pathogens was not complete resistance.The induced resistant effect(IRE) increased as CWE concentration increased,however,IRE had somehow satura-ted concentration of CWE.Induced nonhost resistance by incompatible pathogen was quantitative to other compatible pathogens.The induced resistance was best at 2 or 3 d after CWE treatment,and then decreased.IRE was about 20 percent in 10 d after CWE treatment.     

Maternal salinity improves yield,size and stress tolerance of Suaeda fruticosa seeds

Shrubby seablite or lani(Suaeda fruticosa Forssk)is a perennial euhalophyte with succulent leaves,which could be planted on arid-saline lands for restoration and cultivated as a non-conventional edible or cash crop.Knowledge about the impacts of maternal saline environment on seed attributes of this important euhalophyte is lacking.This study investigated the effects of maternal salinity on yield,size and stress tolerance of S.fruticosa seeds.Seedlings of S.fruticosa were grown in a green net house under increasing maternal salinity levels(0,300,600 and 900 mM NaCl)until seed production.Total yield,size,stress tolerance and germination of the descended seeds under different maternal saline conditions were examined.Plants grown under saline conditions(300,600 and 900 mM NaCl)produce a substantially higher quantity of seeds than plants grown under non-saline condition(0 mM NaCl).Low maternal salinity(300 mM NaCl)improves seed size.Seeds produced under all maternal salinity levels display a higher tolerance to low temperature(night/day thermoperiod of 10℃/20℃),whereas seeds produced under 300 mM NaCl maternal saline condition show a better tolerance to high temperature(night/day thermoperiod of 25℃/35℃)during germination.Seeds from all maternal saline conditions germinate better in the 12 h photoperiod(12 h light/12 h dark)than in the dark(24 h dark);however,seeds produced from low and moderate maternal saline conditions(300 and 600 mM NaCl)show a higher germination in the dark than those from control and high maternal saline conditions(0 and 900 mM NaCl).In general,maternal salinity is found to improve yield,size and stress tolerance of S.fruticosa seeds.     

Optimization of reed-specific degrading bacteria by re-sponse surfaces for remediation of crude oil-polluted soil in Xinjiang, China

This paper discussed the optimization of conditions for remediation of crude oil-polluted soil based on pot experiment by applying reed-specific degrading bacteria,and using response surfaces methodology.We took the initial crude oil concentration,the amount of inoculation,the ratio of nitrogen and phosphorus,and the use of surfactant(Tween-80)as independent variables(factors),and the degrading ratio of crude oil as the dependent variable(response)after a 90-day experiment.The experiment explored the impacts of each independent variable and their interactions on the bioremediation of crude oil-polluted soil using the Box-Behnken design.Working with a simulated forecasting model the study obtained optimization values for the treatment parameters of 200 g/kg of the reed+specific degrading bacteria,a nitrogen to phosphorus ratio of about 6.0,and 0.2% surfactant.Under experimental conditions,for crude oil concentrations of 10,30 and 50 g/kg,the optimal effects of the treatments achieved 71.87%,66.61% and 54.52% degradation of the crude oil,respectively.The results can provide a basis for the technical development of plant-microorganism combined bioremediation of crude oil-polluted soil.     

盐胁迫下交替呼吸对二斑叶螨侵染叶片及其间接防御的影响

为探索在遭受盐胁迫时二斑叶螨Tetranychus urticae Koch侵染叶片的交替呼吸途径的生理学功能,在实验室条件下研究了NaCl以及水杨基氧肟酸对二斑叶螨侵染叶片的间接防御反应,以及对过氧化氢含量和细胞死亡水平的影响。200 mmol/L NaCl胁迫没有明显影响二斑叶螨侵染叶片对智利小植绥螨Phytoseiulus persimilis的吸引作用,也没有提高二斑叶螨侵染叶片中过氧化氢含量和细胞死亡的水平,但显著提高了侵染叶片中交替呼吸途径的水平。200 mmol/L NaCl和1mmol/L水杨基氧肟酸的复合处理则显著降低了二斑叶螨侵染叶片对捕食螨的吸引作用,并提高了过氧化氢含量和细胞死亡的水平。研究表明,当二斑叶螨侵染叶片遭受盐胁迫时,交替呼吸途径不仅有助于维持植物的间接防御反应,而且缓解了植物体内的氧化压力和细胞死亡。     

黑麦草幼苗对NaHCO3胁迫的生理响应

采用营养液砂培方法,研究了不同浓度NaHCO3(0、50、100、150 mmol/L和200 mmol/L)胁迫对黑麦草幼苗生长、活性氧代谢和渗透溶质积累的影响。结果表明:(1)随着NaHCO3浓度增加,黑麦草幼苗鲜、干重呈降低趋势,叶片超氧阴离子(O2.)、过氧化氢(H2O2)、丙二醛(MDA)和Na+含量不断升高,过氧化氢酶(CAT)、过氧化物酶(POD)活性和抗坏血酸(AsA)、谷胱甘肽(GSH)、K+含量及K+/Na+持续下降,超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)活性呈先升后降变化,液泡膜H+-ATPase和H+-PPase活性在NaHCO3浓度为50～150 mmol/L时高于对照,NaHCO3浓度为200 mmol/L时低于对照。(2)碱胁迫降低了幼苗叶片中可溶性蛋白质和游离氨基酸的含量,提高了可溶性糖和脯氨酸的含量。表明活性氧代谢和Na+、K+平衡失调及积累有机溶质进行渗透调节需更多能耗等可能是碱胁迫下黑麦草幼苗生长受抑的重要因素。     

松油烯-4-醇对淡色库蚊的熏蒸毒力及对其Na+ ,K+ -ATP酶的抑制作用

为进一步探讨杀虫植物砂地柏Sabina vulgaris Ant.精油中主要杀虫活性成分—松油烯-4-醇(terpinen-4-ol)对卫生害虫的生物活性,测定了该物质对淡色库蚊Culex pipiens Pallens及其Na+,K+-ATP酶活性的影响。结果表明:松油烯-4-醇对淡色库蚊具有较强的熏蒸作用,其LC50值为6.79 mg/L, 在LC80剂量下其击倒中时(KT50)为6.92 min;淡色库蚊Na+,K+-ATP酶活性测定的最佳反应条件为pH值7.42、温度35.5℃、底物浓度0.7 mmol/L;离体和活体情况下,松油烯-4-醇均可显著抑制淡色库蚊Na+,K+-ATP酶的活性,其I50值为32.02 μg/mL。Na+,K+-ATP酶可能是松油烯-4-醇对淡色库蚊的杀虫作用靶标。     

盐胁迫对不同基因型冬小麦发芽和出苗的影响

研究了不同浓度NaCl胁迫对4种不同基因型冬小麦种子发芽及出苗的影响。试验结果表明,50～150mmol/LNaCl处理对小偃6号和NR9405发芽的抑制作用较小,50、100mmol/LNaCl处理对陕229和RB6的发芽有一定促进作用;150～200mmol/L的盐浓度可能是影响小麦种子萌发的临界浓度。盐胁迫下,小麦种子发芽率、发芽指数及活力指数下降,且活力指数对盐害反应最为敏感。盐胁迫抑制小麦发芽期间芽和根生长,且在低盐浓度(50mmol/L)下根受抑制敏感程度大于芽;盐浓度上升则相反。小麦根数在低盐浓度(50mmol/L)下增加,高盐浓度(>150mmol/L)下减少。盐胁迫下,小麦种子出苗延迟,出苗率下降。不同基因型小麦发芽过程对盐胁迫的反应不同。小麦种子耐盐性存在基因型差异,4个冬小麦品种中,小偃6号种子耐盐性相对较好,NR9405次之。陕229和RB6耐盐性相对较差。     

抑霉唑的毛细管电泳手性拆分及其在线富集

采用毛细管电泳法对抑霉唑进行手性拆分，研究了手性选择剂β-环糊精 (β-CD)、有机添加剂、NaH₂PO₄、NH₄H₂PO₄和分离电压对手性拆分的影响；同时，采用堆积法对抑霉唑进行在线富集，研究了进样压力和进样时间对在线富集的影响。结果表明:在分离电压为20 kV、β-CD浓度为5 mmol/L及缓冲体系为2.5% 异丙醇 + 75 mmol/L NaH₂PO₄ + 5 mmol/L NH₄H₂PO₄时，抑霉唑获得最佳分离度，分离度可达3.0；在分离电压为20 kV、β-CD浓度为5 mmol/L、缓冲体系为75 mmol/L NaH₂PO₄ + 5 mmol/L NH₄H₂PO₄ + 50 mmol/L H₃PO₄及进样条件为13.8 kPa × 99.9 s时获得最高富集倍数，富集倍数达91~92倍。     

4种化学物质对南瓜抗白粉菌产生过敏性反应影响的研究

研究了4种化学物质对南瓜抗白粉病产生过敏性反应的影响,结果表明H2O2+接菌处理可使南瓜叶片中过敏性细胞数量增加,且随着浓度的升高过敏性细胞数量逐渐增多,经20mmol/L H2O2 + 接菌处理的南瓜叶片,在96h时产生的过敏性细胞比对照多81个/cm2; 而活性氧清除剂过氧化氢酶、抗坏血酸和谷胱甘肽3种化学物质处理+接菌南瓜叶片后,叶片中过敏性细胞的数量显著减少,且浓度越高,过敏性细胞数量越少,2000U/mL过氧化氢酶+接菌、20mmol/L抗坏血酸+接菌和40mg/L谷胱甘肽 + 接菌处理南瓜叶片,96h时过敏性细胞数量分别比对照 + 接菌少79、95和90个/cm2; 接菌10d后,20mmol/L H2O2 + 接菌处理的南瓜叶片的病情指数比对照 + 接菌低14.1,2000U/mL过氧化氢酶 + 接菌、20mmol/L抗坏血酸 + 接菌和40mg/L谷胱甘肽 + 接菌处理的南瓜叶片的病情指数分别比对照高7.47、4.95和6.83。     

外源ALA对NaCl胁迫下不同品种西葫芦生理特性及产量的影响

以2个耐盐性不同的西葫芦品种翡翠二号(耐盐性较强)和新早青一代(耐盐性较弱)为材料,研究了叶面喷布5-氨基乙酰丙酸(ALA)对200 mmol/L,400 mmol/L NaCl胁迫下西葫芦生长某些生理特性及果实产量的影响.结果表明,外源ALA对200 mmol/L NaCl胁迫下盐敏感品种的生长及生理特性的缓解作用较好,而在400 [ HTSS]mmol/L NaCl胁迫下ALA对耐盐性较强的翡翠二号的缓解作用显著.ALA处理可提高NaCl胁迫下西葫芦叶片的叶绿素、可溶性蛋白及脯氨酸含量,降低细胞膜透性,抑制MDA产生,增加西葫芦植株对盐胁迫的抵抗能力,显著提高盐胁迫下西葫芦产量.     

Effects of water stress and NaCl stress on different life cycle stages of the cold desert annual Lachnoloma lehmannii in China

For a plant species to complete its life cycle in arid and saline environments, each stage of the life cycle must be tolerant to the harsh environmental conditions. The aim of the study was to determine the effects of water stress (water potentials of -0.05, -0.16, -0.33, -0.56, -0.85 and -1.21 MPa) and NaCl stress (50, 100, 200, 300, 400, 500 and 600 mmol/L NaCl) on seed germination percentage, seedling survival and growth, juvenile growth and plant reproduction of Lachnoloma lehmannii Bunge (Brassicaceae), an cold desert annual that grows in the Junggar Basin of Xinjiang, China in 2010. Results indicated that low water stress (-0.05 and -0.16 MPa) had no significant effect on seed germination percentage. With a decrease in water potential, germination percentage decreased, and no seeds germinated at -0.85 and -1.21 MPa water stresses. Germination percentage of seeds was significantly affected by NaCl stress, and higher germination percentages were observed under non-saline than saline conditions. An increase in NaCl concentrations progressively inhibited seed germination percentage, and no seeds germinated at ≥400 mmol/L NaCl concentration. Non-germinated seeds were transferred from both PEG (polyethylene glycol-6000) and NaCl solutions to distilled water for seed germination recovery. The number of surviving seedlings and their heights and root lengths significantly decreased as NaCl stress increased. About 30% of the plants survived and produced fruits/seeds at 200 mmol/L NaCl concentration. Thus, seed germination, seedling establishment and reproductive stage in the life cycle of L. lehmannii are water- and salt-tolerant, with seedlings being the least tolerant. These tolerances help explain why this species can survive and produce seeds in arid and saline habitats.