Col生态型拟南芥AP3基因启动子克隆及植物表达载体构建

隶属于MADS-Box基因家族的拟南芥花器官B类特征基因APETALA3 (AP3)在花瓣和雄蕊中特异性地表达;AP3基因编码转录因子,与A类和C类特征基因协同作用控制双子叶植物花瓣和雄蕊的发育.研究表明AP3基因启动子为花特异表达启动子.因此,AP3基因启动子的克隆及功能鉴定对于园林植物与花相关的商业性状的定向改良具有重要作用.本文根据GenBank数据库报道的Ler生态型拟南芥(Arabido-psis thaliana) AP3基因启动子序列(U30729)设计了一对特异性扩增引物,基于PCR技术,用高保真的KOD-plus DNA聚合酶扩增了长度为1 767 bp的Col生态型拟南芥AP3基因启动子,并命名为pAtAP3,其GenBank登录号为FJ619533.Bl2seq在线分析表明pAtAP3与U30729序列的相似性达98%,与Col生态型拟南芥BAC克隆T12E18 (AL132971) 9 264～11 030之间的碱基序列相似性达100%,且该段序列的下游基因编码AP3蛋白(CAB81799),说明克隆序列为Col生态型拟南芥AP3基因的启动子.PLACE在线分析表明pAtAP3具有基本的启动子元件TATA-box和CAAT-box,还包含大量与花特异表达相关的顺式元件CArG1、CArG2、CArG3和anther-box等.本试验进一步构建了植物表达载体pAtAP3::GUS,为该启动子的功能鉴定奠定了基础.     

不同生态型扁蓿豆光合特性和光适应能力

用Li-6400型便携式光合作用测定系统和配套的荧光叶室,对4个不同生态型扁蓿豆的光合特性和光适应能力进行了比较研究。结果表明：内蒙古土默特左旗的生态型00-61扁蓿豆和黑龙江松嫩草原的生态型93-21扁蓿豆最大净光合速率（P_max）、实际光化学效率（Ф_PSⅡ）、光化学荧光猝灭系数（q_P）、暗呼吸速率（R_d）均较高,而非光化学荧光猝灭系数（q_N）较低,表明二者具有相对高产的生理和生物物理基础。00-61扁蓿豆还具有较高的光饱和点,对强光有更大的光合适应性,适合种植在相对高光环境。内蒙古正蓝旗浑善达克沙地的生态型90-36扁蓿豆,q_P较低而q_N较高,具有相对较强的防御光抑制破坏的能力。内蒙古锡林郭勒盟锡林浩特典型草原区的生态型00-81扁蓿豆,光补偿点和光饱和点均较低,耐荫力较强,与其他生态型相比更能适应相对弱光环境。     

辽宁太子河河岸带草本植物特征研究

应用样方法研究了辽宁太子河河岸带草本物种组成特征。结果表明：1）太子河河岸带共有草本植物207 种,隶属于36 科125 属。其中菊科物种最多,水蓼出现的频率最高;2）太子河河岸带草本植物属级区系组成丰富,以温带分布区类型为主,其次为热带分布区类型;3）所有物种中,水生或湿生植物120 种,旱生或中生植物87 种,分别占总物种数的58.0%和42.0%;4）根据物种在样方中出现与否,将样点分为2 类;一类分布于高海拔地区,物种以旱生或中生植物为主,物种数多,而另一类分布于低海拔地区,物种以水生或湿生植物为主,物种数较少;5）河岸带草本物种中有杂草和人类伴生种出现,且频率较高,表明太子河河岸带受到人类活动,如农田开发、挖沙和人类居住的影响。     

不同居群准噶尔无叶豆果实和种子特性及种子萌发差异

研究准噶尔无叶豆(Eremosparton songoricum) 6个居群间果实和种子特性及种子萌发差异, 以揭示异质生境下准噶尔无叶豆果实和种子的生态适应机制。结果显示: 居群间准噶尔无叶豆的植株距离(F = 2.34, p = 0.03)和植株冠幅(F = 8.49, p < 0.01)存在显著差异, 沙漠北缘E、F居群和沙漠腹地C居群(受人类干扰剧烈)的植株距离和植株冠幅高于沙漠腹地A、B、D居群; 居群间准噶尔无叶豆果实和种子的长度、宽度、厚度、重量存在显著差异, 居群E、F和C的大部分参数显著高于其他沙漠腹地居群; 居群间果实多子性(F = 6.96, p < 0.01)也存在显著差异, 居群C的果实多子性最高((32.50 ± 4.79)%); 萌发结果表明, 居群间新鲜的成熟种子萌发不存在显著差异, 且萌发率都低于15%; 所有居群的大部分种子都存在物理性休眠现象, 人为划破种皮能显著提高种子萌发率, 但在低温(15/5 ℃)条件下, 所有居群的种子萌发率都较低, 说明低温抑制了种子萌发; 经人为划破种皮解除物理休眠后, 种子的休眠没有完全释放, 居群C、E和F (大种子居群)的种子萌发率显著高于居群A、B和D (小种子居群) (F = 30.77, p < 0.01), 说明准噶尔无叶豆种子不仅存在物理性休眠现象, 也可能存在生理休眠现象。不同程度的种子复合休眠可能是准噶尔无叶豆不同居群适应古尔班通古特沙漠的重要生存策略。     

沙地云杉生态型对干旱胁迫的生理生态响应

采用干旱胁迫处理不同生态型沙地云杉幼苗,对其主干高生长、丙二醛(MDA)、脯氨酸和叶绿素含量进行了测定．结果表明,沙地云杉幼苗高生长明显受到干旱胁迫的抑制,绿果型沙地云杉在水分条件良好的情况下,高生长迅速,明显高于紫果型沙地云杉．随着干旱胁迫强度的增强,其高生长受抑制的程度高于紫果型沙地云杉．红果型沙地云杉处于二者之间．同时干旱胁迫也影响沙地云杉生长进程,使得其封顶时间提前一个多月．MDA含量无论在叶还是根中呈上升趋势,只是在土壤含水量在10％左右出现轻度胁迫时略有下降;叶片中MDA含量明显高于根中;从不同生态型来看,紫果型沙地云杉体内MDA含量高,绿果型低且具有较大的变化幅度．脯氨酸含量随干旱胁迫强度增加而增加;绿果型沙地云杉根部脯氨酸含量在处理4之前高于另外两种生态型．叶绿素的变化规律,紫果型和红果型沙地云杉基本相同,只是红果型含量略微低于紫果型．其叶绿素a、叶绿素b和总叶绿素含量都是开始逐渐升高;随着胁迫强度增加,叶绿素含量下降;绿果型沙地云杉叶绿素含量总体上都呈下降趋势,只有叶绿素b含量在胁迫初期有所增加．从叶绿素a／b值出现下降趋势,但不同生态型表现不一样．绿果型沙地云杉由最高下降到最低,紫果型沙地云杉下降幅度较小,红果型介于二者之间．表明不同生态型沙地云杉抗旱能力不同,紫果型>红果型>绿果型．     

Comparison of Plasma Membrane H^＋-ATPase Activity in Two Ecotypes of Reed （Phragmites communis） Leaves from Different Habitats

Plasma membrane (PM) vesicles of the leaves of two ecotypes of reed (Phragrnites communis Trin.), swamp reed (SR) and heavy salt meadow reed (HSMR) growing in the desert region of Northwest China, were purified by two-phase partitioning and the properties of their PM H^ -ATPases (EC 3.6.1.35) were compared. The specific activity of this enzyme was greater in HSMR than in SR and the Km lower (1.27mmol/L in SR and 0.30mmol/L in HSMR), and the Vmax of ATP hydrolysis activity showed no significant difference between the two ecotypes. The PM H^ -ATPase was more sensitive to denaturing temperatures in HSMR than in SR, and the pH profile also showed a slight difference, suggesting that the catalytic mechanism of this enzyme was different in HSMR compared with that in SR. The p-nitrophenyl phosphate (PNPP) hydrolysis activity of H^ -ATPase was higher in HSMR than in SR at low concentrations of PNPP, but showed no difference at high PNPP concentration. The Km for PNPP hydrolysis was 3.61mmol/L and 1.92mmol/L in SR and HSMR, respectively. And the Vmax of PNPP hydrolysis showed no significant difference in the two reed ecotypes. An experiment with the inhibitor vanadate showed that the catalytic mechanisms of the phosphatase domain of the ATPase were different in the two ecotypes. The data obtained following trypsin treatment showed a difference in the enzyme activity pattern, suggesting that there existed a possible change in the C-terminus of the ATPase, either in the structure or in the property or both of them. In addition, compared with SR, the ATP-dependent H^ pumping activity of ATPase and the coupling between proton transport and ATP hydrolysis in HSMR were increased. These results indicated that the properties of PM H^ -ATPase were changed in HSMR with compared to those in SR, which might include enzyme modifications and different isoforms expressed. The alterations of the properties of this enzyme might be an adaptive response to the habitat.     

生物的辐射适应和趋同适应

介绍了生物的辐射适应和趋同适应的特点,并对2类适应结果在应用中的作用进行了说明。