异源表达玉米ZmC3H54基因增强水稻的耐旱性

CCCH锌指蛋白是一类重要的转录调控因子。从玉米中分离得到一个受干旱和ABA诱导表达的CCCH型锌指蛋白基因ZmC3H54，通过构建过量表达载体并转化水稻来进一步研究其功能。 与对照组相比，转基因植株在干旱胁迫处理下具有更高的相对含水量与存活率以及较低的相对电导率，表明过量表达ZmC3H54基因可以提高转基因水稻的耐旱性。此外，转基因水稻幼苗对外源ABA敏感性更高。以上结果表明玉米ZmC3H54基因可能是通过ABA信号通路调控植物对干旱的耐受性。     

外源ABA对低温胁迫下小豆幼苗生理及产量的影响

在盆栽条件下，以耐冷性不同的2个小豆(Vigna angularis）品种龙小豆4号（耐冷型）和天津红（冷敏型）为材料，于苗期在人工气候室进行低温（4℃，持续12 h）及预喷施外源脱落酸（abscisic acid，ABA）处理，旨在研究苗期低温胁迫下外源ABA对小豆叶片逆境生理指标（H₂2O₂2、丙二醛（MDA）、抗氧化酶活性、可溶性物质）和产量因子的调控效应。结果表明：幼苗期低温处理12 h后，龙小豆4号和天津红小豆叶片H₂2O₂2含量分别提高34.82%和27.10%；MDA含量分别提高65.56%和83.79%；SOD和POD活性分别提高6.67%和18.48%、45.53%和102.44%；脯氨酸含量分别提高33.12%和24.41%。低温处理导致龙小豆4号百粒重下降2.58%，与喷施清水相比，低温处理12 h后天津红的单株荚数和百粒重分别下降18.55%和10.61%(P＜0.05）。喷施外源ABA具有抵御低温的作用，外源ABA促进龙小豆4号和天津红叶片脯氨酸含量提高9.13%和19.76%；H₂2O₂2含量降低7.63%和8.36%；MDA含量降低10.18%和20.27%；SOD和POD活性分别提高9.06%和13.57%、8.26%和28.51%，同时百粒重分别提高8.56%和8.92%。低温胁迫下，不同品种小豆的生理应激存在显著差异；喷施外源ABA能够有效缓解低温胁迫对小豆的伤害。     

外源褪黑素和脱落酸对干旱胁迫下葡萄生理特性的影响

为了探讨褪黑素(MT)和脱落酸(ABA)两者混合施用对植物响应干旱胁迫的综合效应,以盆栽‘阳光玫瑰’葡萄为材料,通过根灌100μmol·L~(-1)的MT溶液和叶面喷施50μmol·L~(-1)的ABA溶液及二者组合处理,研究MT和ABA对干旱胁迫下葡萄生理特性的影响。结果表明,与干旱对照组(D_(ck))相比,MT处理导致葡萄叶片MDA、H_2O_2含量和相对电导率分别降低了14.42%、44.11%和21.26%,叶片相对含水量提高了1.12%,同时SOD和POD酶活性分别提高了14.00%和3.01%。这些均表明MT处理有效缓解了干旱胁迫对植株造成的损伤。50μmol·L~(-1 )的ABA处理组叶片MDA含量和相对电导率较干旱对照组提高了9.43%和17.25%,表明ABA处理没有缓解植株的胁迫状态。MT和ABA组合处理具有和MT处理类似的效果。结果表明,褪黑素可以通过减轻膜脂过氧化程度,增强抗氧化系统能力,从而缓解干旱胁迫对葡萄的氧化损伤,提高抗旱性;同时削弱ABA带来的负面效应。     

苹果细胞分裂素氧化酶基因MdCKX7.2的克隆及抗性鉴定

采用同源克隆和PCR技术从‘嘎拉’苹果(Malus×domestica Borkh.)中克隆细胞分裂素氧化酶基因MdCKX7.2(基因序列号:MDP0000279125)。该基因含有1 542 bp的完整开放阅读框,编码513个氨基酸。利用Plant CARE数据库对MdCKX7.2启动子顺式作用元件进行预测分析,发现MdCKX7.2启动子序列中存在光、干旱、脱落酸、水杨酸、茉莉酸甲酯等响应元件。基因表达分析发现,‘嘎拉’幼苗中MdCKX7.2的表达明显受干旱和ABA的诱导。通过农杆菌介导的遗传转化获得MdCKX7.2转基因拟南芥植株。抗性试验表明,异位表达MdCKX7.2基因明显提高了拟南芥对干旱胁迫的抗性。拟南芥种子萌发试验表明,在拟南芥中异位表达MdCKX7.2提高了植株对ABA的敏感性,种子萌发率和幼苗鲜质量明显下降,与种子萌发相关基因的表达量明显上调。以上试验结果表明,MdCKX7.2在植物非生物胁迫响应中发挥重要作用。     

东农冬麦1号TaPRK基因的生物信息学分析及低温和ABA、SA、MeJA对其表达模式的影响

磷酸核糖激酶(PRK)是卡尔文循环的关键酶,在调节糖代谢过程中起着关键作用。为探索TaPRK在小麦抗逆过程中的功能,以强抗寒冬小麦品种东农冬麦1号(Dn1)和弱抗寒冬小麦品种济麦22(J22)为材料,对TaPRK进行生物信息学分析和表达模式研究。结果表明,TaPRK基因含有一个1 215bp开放阅读框,编码404个氨基酸,表达产物为稳定的亲水蛋白,属于尿苷激酶家族,带有叶绿体转运肽,定位于叶绿体。越冬期间,Dn1分蘖节中TaPRK的相对表达量显著高于J22,Dn1叶片中TaPRK的相对表达量在-10℃和-25℃时高于J22,而在0℃时低于J22;外源ABA、SA和MeJA处理下,Dn1分蘖节中TaPRK的相对表达量均随着温度的降低表现为先升后降的趋势,且均在-10℃时达到表达量的峰值;外源ABA和SA处理下Dn1叶片中TaPRK的相对表达量呈现"降-升-降"的变化规律,在-10℃时显著高于对照;外源MeJA处理下,Dn1叶片中TaPRK的相对表达量在0℃和-25℃高于对照,且在0℃达到峰值。总体来说,TaPRK在小麦抗寒方面发挥正向调节作用。外源ABA、SA和MeJA增加了冬小麦TaPRK的表达量,有助于提高冬小麦的抗寒性。     

Sensitivity of Two Quinoa (ChenopodiumquinoaWilld.) Varieties to Progressive Drought Stress

Quinoa (ChenopodiumquinoaWilld.) is a highly nutritious Andean seed crop which shows great potential to grow under a range of hostile environments. The objective of this study was to investigate the differences of drought tolerance of a Bolivian (Achachino) and a Danish (Titicaca) variety, and especially drought‐related adaption strategies. Soil water status was expressed as the fraction of transpirable soil water (FTSW). Relative stomatal conductance (RSC), relative transpiration (RT) and relative leaf water potential (RLW) were calculated by determining stomatal conductance, transpiration rate and leaf water potential of the drought‐treated plants relative to those of fully irrigated plants. The responses of RSC, RT and RLW to decreasing FTSW were described by a linear‐plateau model. The critical value of FTSW was the threshold of FTSW where the parameters studied decreased. The thresholds increased C_S for stomatal conductance, C_T for transpiration and C_Lfor leaf water potential. Achachino showed significantly lower C_T and C_L when compared with Titicaca, implying that transpiration and leaf water potential were less affected under mild drought conditions in the Bolivian variety. C_S in Achachino was significantly higher than C_L and C_T, which indicated that stomatal conductance declined before transpiration and leaf water potential were reduced. Such difference was found in Titicaca where reduction of leaf area had more effect on transpiration than stomatal closure. Slower growth rate and smaller leaf area in combination with a lower stomatal conductance was found to contribute to drought resistance in Achachino. ABA concentration in the xylem sap tended to increase in both varieties after 2 days onset of drought, prior to decline in leaf water potential. Titicaca showed significantly (P < 0.05) higher ABA concentration when compared with Achachino under both fully irrigated and drought conditions. Titicaca had higher xylem nutrient concentration in comparison with Achachino in both fully‐watered and drought plants at day 2 after onset of soil drying. It was concluded that Titicaca was more sensitive to progressive drought than Achachino which avoided water loss by means of lower growth rate and smaller leaf area.     

银杏种子后熟生理与内源激素变化的研究

研究银杏种子后熟期间的生理变化以及内源激素对种子休眠与萌发过程的调控作用.结果表明:银杏种胚分化不完全、发育不充分是种子休眠的主要原因,银杏种子的后熟过程实质上是种胚不断分化生长的过程.在此过程中,物质代谢、酶活性的变化均有利于种胚发育和种子发芽,种子内部经历了一系列生理生化变化去调整内源激素平衡、完成种胚发育.研究发现,内源激素在银杏种子休眠与萌发过程中起着重要的作用:GA1 3是银杏种胚后熟的关键物质;ZRs对银杏种子生长起重要的促进作用;GA1 3/ABA及ZRs/ABA相对比例的变化对种子发育、胚的后熟及种子萌发均有重要的影响.     

细胞分裂素:杨树气孔运动的调节剂

通过在三种杨树无性系，Ｉ－２１４（Ｐｏｐｕｌｕｓ×ｅｕｒａｎｅｒｉｃａｎａｃｖ．Ｉ－２１４）（ｌｔａｌｉｃａ）、中东杨（Ｐ．ｂｅｒｏｌｉｎｅｎｓｉｓ）（Ｂｅｒｏｌｉｎｅｎｓｉｓ）和群众杨（Ｐ．ｐｏｐｕｌａｒｉｓ３５－４４）（Ｐｏｐｕｌａｒｉｓ）一年生盆栽插条苗的木质部导入ＡＢＡ和细胞分裂素，研究了这两类激素在气孔调控中的作用。尽管不同无性系的气孔在对ＡＢＡ的敏感性上存在显著差异，但ＡＢＡ仍可导致气孔的关闭，然而在蒸腾流中的细胞分裂素（与ＡＢＡ共导入或分别导入）可以明显地抑制ＡＢＡ的作用。并且玉米素还能推迟土壤干旱所诱导的气孔关闭，在水分胁迫条件下，内源细胞分裂素浓度下降而同时ＡＢＡ上升．据此提出了复合胁迫信号的概念，即在根冠通讯中，是ＡＢＡ和细胞分裂素共同调控气孔的运动。另外还研究了玉米素、激动素、６－ＢＡ等不同细胞分裂素与ＡＢＡ的相互作用，结果发现６－ＢＡ与玉米素和激动素的作用相反，它不能抑制ＡＢＡ的作用，反而促进其对气孔的关闭     

沙棘不落果原因探讨

沙棘果实成熟与衰老时均不脱落,甚至干缩在果枝上,为了研究沙棘不落果原因,寻求促进落果的有效方法,我们进行了下列实验。一、材料与方法 (一)外施乙烯与ABA于果实完熟前期(9月中下旬)剪取中国沙棘(Hippophaerhamnoides L.Subsp.Sinesis)、西藏沙棘(H.thibetana Schlechtend)带叶果枝,将下端分别浸于装有500、1000ppm乙烯利,50、100ppm ABA与50、100ppm6-康基氨基腺     

Changes of plasma membrane H<Superscript>+</Superscript>-ATPase activities of <Emphasis Type="Italic">Glycine max</Emphasis> seeds by PEG treatment

The soybean （Glycine max） Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol （PEG） treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolytic ATPase in plasma membranes and H^＋-pumping responses in soybean seeds were investigated during PEG treatments. Effects of exogenous calcium and exogenous ABA on the hydrolytic ATPase were also examined in order to understand the mechanism of chilling resistance. Highly purified plasma membranes were isolated by 6.0% aqueous two-phase partitioning from soybean seeds, as judged by the sensitivity of hydrolytic ATPase to sodium vanadate. PEG treatment resulted in a slight increase of the hydrolytic ATPase activity in 12 h. Then the activity decreased gradually, but still higher than the control. The H^＋-pumping activity increased steadily during PEG treatment. Exogenous calcium had both activating and inhibiting effects on the hydrolytic ATPase, but the activity was inhibited in soybean seeds treated with exogenous ABA. Results suggested that PEG treatment, not the exogenous calcium and ABA, up-regulated H^＋-ATPase activities in soybean seeds.