Contribution of mineral nutrition to the response of barley seedlings to polyethylene glycol–induced mild water stress

The effect of polyethylene glycol–induced osmotic stress on the activity of nitrate reductase, glutamine synthetase, and glycolate oxidase in leaves of young barley plants grown under two nutrient‐supply regimes was studied. The activity of nitrate reductase gradually decreased after polyethylene glycol (PEG) application, while glutamine synthetase and glycolate oxidase were increased. It is speculated that the enhanced glutamine synthetase and glycolate oxidase activities are due to increased flux of metabolites through the photorespiratory cycle. Prominent increase in concentrations of free proline, reducing sugars, and free amino acids was observed. The possible contribution of these cellular solutes to the process of osmotic adjustment and the role of mineral supply is discussed. It is suggested that low N supply in combination with stress conditions switched the preferred osmolyte type from amino acids (N‐containing) to sugars (C‐containing).     

旱后复水条件下转基因甘薯体内脯氨酸含量变化及其抗氧化作用

以转铜锌超氧化物歧化酶（Cu/Zn SOD）和抗坏血酸过氧化物酶（APX）基因甘薯（TS）及未转基因甘薯（NT）为实验材料,研究在旱后复水条件下转基因甘薯及未转基因甘薯抗氧化酶活性变化以及体内Pro含量的变化与抗氧化的关系。结果显示,连续36 h胁迫条件下,TS和NT的SOD活性都先降低后升高,但TS的SOD活性始终高于NT。复水后二者SOD活性都下降。持续胁迫时,TS的APX活性先升高后降低,NT与之相反,复水后TS和NT的APX活性都是先升高后降低,复水12 h,TS的APX活性是NT1.5倍.正常条件下和水分胁迫12 h、36 h,复水12、24 h、转基因甘薯体内Pro含量显著高于未转基因甘薯。水分胁迫条件下TS的膜质受伤害程度要轻于NT。实验结果表明,同时转入SOD、APX抗氧化基因后,在胁迫条件下,转基因甘薯可以更好的对植株体进行保护,及复水条件下转基因甘薯可以更好进行修复,抗氧化系统可以影响脯氨酸的积累。     

Evaluation of cold resistance of ornamental species for planting as urban rooftop greening

Rooftop gardening or green roof establishment, one of the methods of afforestation for urban greening, has many benefits for the environment, the economy and urban landscapes. Various environmental stresses including heat, strong wind, sunshine and cold prevent most plants from growing well in extensive green roof systems. For the establishment of urban rooftop gardening in Beijing, we evaluated 13 ornamental plant species [Berberis thunbergii ‘Atropurea Nana’, Euonymus fortune (Turcz.) Hand., Viburnum dilatatum Thunb., Cotinus coggygria Scop., Swida alba Opiz., Weigela florida (Bunge.) A. DC., Jasminum nudiflorum Lindl., Euonymus japonicus Thunb., Euonymus japonicus ‘Cuzhi’, Buddleja davidii Franch., Pyracantha fortuneana (Maxim.) Li., Ligustrum lucidum Ait. and Spiraea salicifolia L.] for greening of flat rooftops. We obtained three indices concerning cold resistance, i.e., electrical conductivity of leaves, amounts of soluble sugars and amounts of free proline, providing a theoretical basis for selection of plants fit for roof and balcony greening. The results show that the six species P. fortuneana (Maxim.) Li., B. thunbergii ‘Atropurea Nana’, J. nudiflorum Lindl., E. fortune (Turcz.) Hand., E. japonicus Thunb. and E. japonicus ‘Cuzhi’ are excellent plants for rooftop gardening, judging from their strong ability in cold resistance. Plants such as L. lucidum Ait., C. coggygria Scop. and W. florida (Bunge) A. DC. showed a medium ability in cold resistance. However, these species can be used in roof and balcony greening after intensive management or acclimatization of variety. The ability to resist cold of plants such as W. florida (Bunge) A. DC., S. salicifolia L., V. rhytidophyllum and S. alba Opiz. (Cornus alba L.) was found to be rather weak. Therefore, cold-proof measures are recommended when using these species.     

干旱胁迫与抗蒸腾剂对喜树几项生理指标及喜树碱含量的影响

经过12d的干旱胁迫，喜树叶内Fpro和MDA含量分别升高了46．7％和19．06％，是同期对照的138．93％的117％；Pn降为负值；Tr和Sc显著下降，降低幅度分别为58．28％和75％；且随着胁迫时间的延长，变化幅度逐步增大。抗蒸腾剂可有效地缓解胁迫对喜树的不良影响。短期干旱胁迫可使叶内喜树碱的含量明显提高，在生产中可由此而提高喜树碱的产量。     

辣椒染病毒株与健株花药中游离脯氨酸含量和花粉萌发力的比较

对辣椒感染病毒病植株与健康植株花药中的游离脯氨酸和花粉萌发力进行了比较性研究,结果表明,从开花前7天到开花当天,病株花药中的游离脯氨酸含量均比同期健株的低,但以开花前4天到开花当天的差异较明显,开花前1天病株花药中游离脯氨酸含量比健株的低26.24％～39.96％,开花当天病株上的花粉萌发率比健株的低14.35％～33.31％。本研究结果从一个侧面反映了辣椒感染病毒病后在生理生化上发生的病理变化。     

苧麻不同品种(系)抗旱性的测定及其水分生理研究

1991年对9个不同苧麻品种(系)的4个抗旱性生理指标进行了测定,结果表明:2117-9、华苧一号和5261-5是3个抗旱性很强的品种(系)。在干旱条件下,抗旱品种通过增加脯氨酸含量以减少水分损失,提高渗透调节能力,缓解干旱引起的原生质膜伤害。对华苧一号进行水分胁迫研究表明,在土壤含水量为2%～7%时,植株水分亏缺值为30.00%,自由水与束缚水比值为1.28,植株停止生长而趋于死亡。     

喷施多效唑对盐胁迫下紫羊茅脯氨酸含量和膜透性的影响

本文采用50 mg·L^-1、100 mg·L^-1和200 mg·L^-1等3种浓度的多效唑喷施1%盐胁迫下的冷季型草坪草紫羊茅（Featua fubraL.）,以电导法测定叶片膜透性、茚三酮比色法测定叶片脯氨酸含量,探讨多效唑提高紫羊茅耐盐胁迫能力的效果。结果表明：只有50 mg·L^1浓度的多效唑可以使紫羊茅的脯氨酸含量极显著增高,但对膜透性的影响表现出随多效唑浓度增高膜透性也增高。     

过路黄对低温胁迫的生理反应

为探明过路黄低温致伤的生理特性，为其引种北移、栽培推广提供理论依据，研究了在低温（10，5，0，-5℃）胁迫下过路黄叶片内部生理生化反应的变化情况．结果表明，在低温胁迫下，过路黄叶片的质膜透性、保护酶活性和渗透调节物质均有明显的变化．在试验处理范围内，随着低温胁迫程度的加深和时间的延长，过路黄叶片的质膜透性上升；超氧化物歧化酶（SOD）活性先上升，后下降；游离脯氨酸（Pro）含量有明显增加；丙二醛（MDA）含量呈逐渐上升趋势．     

硒对油菜苗期脯氨酸和丙二醛含量的影响

应用盆栽土培与水培相结合的方式 ,设计不同硒浓度对油菜苗脯氨酸和丙二醛含量的影响 ,试验表明 :各处理脯氨酸含量顺序为 :12 μg .ml-1>15 μg .ml-1>18μg .ml-1>2 1μg .ml-1>2 4 μg .ml-1>9μg/ml-1>对照 ,各处理丙二醛含量顺序为 :2 4 μg .ml-1>2 1μg .ml-1>对照 >15 μg .ml-1>18μg .ml-1>12 μg .ml-1>9μg .ml-1,适量的补硒浓度可降低过氧化产物丙二醛的产生 ,超过一定范围则促进丙二醛的生成。补施硒可提高脯氨酸的含量 ,增强油菜苗的抗性     

四种藤本月季耐盐性的比较

对4个藤本月季品种“西方大帝”、“莫扎特”、“夏令营”、“欢藤”进行了盐胁迫下(NaCl∶Na2SO4=4∶1)形态和生理响应研究.结果表明:盐胁迫对“西方大帝”的株高影响最大,其次为“欢腾”和“莫扎特”,而“夏令营”最小.盐胁迫下,“西方大帝”和“莫扎特”的叶面积下降幅度最大,“夏令营”最小,其中“莫扎特”在盐浓度2‰时,叶面积比对照下降了51.94%.“西方大帝”在盐胁迫处理下,叶片相对含水量显著小于对照,且在4个品种中下降最为明显.在各盐浓度胁迫条件下,4个品种的脯氨酸含量均呈增加趋势,其中“莫扎特”和“西方大帝”随胁迫浓度的增加而显著增加(P<0.05),“夏令营”与“欢腾”在4‰和6‰盐浓度下较2‰盐浓度和对照显著增加(P<0.05).可见,4个品种中,“莫扎特”和“西方大帝”的耐盐性较差,而“夏令营”和“欢腾”的耐盐性较好;且在盐浓度≤2‰的条件下,4个藤本月季品种均对盐胁迫具备一定的缓冲、调节和适应的能力.