短日照诱导对小豆生长发育、光合和荧光参数的影响

为明确短日照对小豆生长发育、光合和荧光参数的影响,采用不同生育时期短日照诱导处理来调查小豆的形态指标、开花时间及开花节位,在开花期和结荚期测定光合作用和叶绿素荧光。结果表明,与对照相比,短日照诱导使小豆的株高降低、平均茎粗和主茎节数变小、白红2号在开花期和结荚期的节间长度升高,唐山红小豆降低;短日照诱导使小豆的花期提前并降低开花节位;短日照诱导使2个品种的净光合速率在开花期明显升高,在结荚期降低,气孔导度、细胞间CO2浓度和蒸腾速率在开花期无明显变化,在结荚期,白红2号明显降低,唐山红小豆升高;短日照诱导对开花期的叶绿素含量无明显影响,在结荚期明显降低,与对照相比,白红2号在开花期和结荚期的Fv/Fm升高,唐山红小豆在开花期变化规律不明显,在结荚期升高;短日照诱导使小豆的产量构成因素及产量呈下降趋势。以上结果说明短日照诱导对花荚期小豆的生长发育、光合参数及产量具有调控作用。     

Water Relation, Photosynthetic Ability and Growth of Thai Jasmine Rice (Oryza sativa L. ssp. indica cv. KDML 105) to Salt Stress by Application of Exogenous Glycinebetaine and Choline

Rice reportedly possesses a very low capacity to accumulate glycinebetaine (Glybet), but may be accumulated by the exogenous application of Glybet or Choline (Cho) as an alternative way to improve its salt‐tolerant ability. The aim of this research was to determine whether Glybet accumulation could be induced in Thai jasmine rice by the exogenous application of Glybet and Cho, and to determine the effects of Glybet and Cho treatment on various growth parameters of seedlings cultured under salt‐stress conditions. Thai jasmine rice seeds were aseptically germinated in vitro on solidified Murashige–Skoog media, supplied with either Glybet or Cho in the culture media for 12 days and then treated with 342 mm NaCl (salt stress) for 4 days. GlyBet content, water relation, photosynthetic capabilities and growth characteristics of salt‐stressed seedlings were measured. The addition of Glybet or Cho to plant culture media containing 342 mm NaCl resulted in increased accumulation of Glybet in rice seedlings. Increased Glybet accumulation was strongly associated with a high efficiency of water usage (r = 0.96), which in turn correlated with increased maximum quantum yield of PSII (F_v/F_m) (r = 0.86). Moreover, the pigment concentrations of seedlings cultured under salt stress were maintained by a function of Glybet, led to high efficiency of photochemical and non‐photochemical quenching of PSII as well as to exhibit on net photosynthetic rate. Thus, our results suggest that the addition of either Glybet or Cho to the plant growth media can improve growth performance under salt stress conditions by increasing the salt tolerance of Thai jasmine rice. The exogenous application of Glybet and/or Cho to culture media may be an effective method of improving resistance to salt stress via the promotion of Glybet accumulation with in rice seedlings.     

模拟酸雨对杨梅生理生化特征的影响

研究了不同强度模拟酸雨对6年生东魁杨梅生理生化特征的影响。结果表明:随着模拟酸雨胁迫加剧,叶片可见伤害症状严重,叶绿素a、叶绿素b、总叶绿素、类胡萝卜素含量以及叶绿素a/b比值显著降低,光系统I(IPSII)的潜在化学活性(Fv/Fo)和最大光化学效率(Fv/Fm)显著降低,水分利用效率和光合能力显著下降,细胞质膜透性增加,MDA含量增加,SOD、POD和CAT活性受到明显抑制,从而抑制杨梅的生长发育。     

绿色荧光蛋白标记解淀粉芽孢杆菌Bam22在油菜体内的定殖

研究GFP标记的解淀粉芽孢杆菌Bam22在油菜植株上的定殖规律,为其开发利用提供科学依据.采用自然转化法将携带绿色荧光蛋白基因的质粒pGFP4412导入Bam22细胞中,构建GFP荧光标记菌株;对比野生型菌株Bam22与标记菌株Bam22-GFP的生长曲线和抑菌能力;通过灌根法,观察标记菌株在油菜体内不同组织部位的定殖...     

Photosynthetic Apparatus Responses to Short‐term low‐temperature Flooding May Contribute to Freezing Tolerance Changes in Forage Grasses

Winter conditions are subjected to rapid climate changes. Increased precipitation and snow melting during warmer winters may result in low‐temperature flooding. These factors probably affect plant overwintering strategies. This study investigated the relationships between the photosynthetic adjustment and freezing tolerance following a short‐term low‐temperature flooding in two forage grasses (Lolium perenne and Festuca pratensis). The effect of flooding on the photosynthetic apparatus acclimation to cold was determined using chlorophyll a fluorescence measurements. Freezing tolerance was estimated using an electrolyte leakage test. It has been shown that genotypes activating non‐photochemical mechanisms of photosynthetic acclimation to cold during low‐temperature flooding may show increased freezing tolerance. Freezing tolerance reduction observed in Festuca pratensis was probably connected with decreased photochemical activity and photoinhibition of photosynthesis. It can be concluded that photosynthetic apparatus response to low‐temperature flooding may contribute to changes in the freezing tolerance. The direction of the changes is associated with different photosynthetic apparatus performance.     

Temperature Before Cold Acclimation Affects Cold Tolerance and Photoacclimation in Timothy (Phleum pratense L.), Perennial Ryegrass (Lolium perenne L.) and Red Clover (Trifolium pratense L.)

The expected temperature rise in late summer/early autumn can change the conditions for acclimation and affect the winter survival of perennial crops. This study examined the effect of the temperature just before the onset of cold acclimation (pre‐acclimation) on freezing tolerance of timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) populations (both cultivars and breeding populations) adapted to either northern or southern parts of Norway. Using phytotron experiments, we studied whether increasing pre‐acclimation temperature delays growth cessation, affects photoacclimation and reduces freezing tolerance. Furthermore, we assessed whether these effects were related to the latitudinal adaptation of the plant material. The results showed that a rise in pre‐acclimation temperature decreased both cold acclimation capacity and photoacclimation in these species. This affected the freezing tolerance, which was reduced significantly more in northern‐adapted population of timothy and perennial ryegrass compared with southern‐adapted populations. Red clover was less affected by temperature changes than the grasses.     

基于日光诱导叶绿素荧光的柑橘黄龙病原位诊断

柑橘黄龙病（Huanglongbing, HLB）是柑橘生产中的毁灭性病害,柑橘植株遭到黄龙病菌侵染后光合能力发生变化而后表现出相应的黄化症状。及早实现HLB的原位快速诊断是防控HLB的重要手段。为探究黄龙病菌侵染柑橘叶片的光合响应机制并实现HLB的原位诊断,该研究分析了健康（Healthy）、未显症HLB（asymptomatic HLB, aHLB）、显症HLB（symptomatic HLB, sHLB）以及黄斑病（Macular,症状与黄龙病相似）柑橘叶片的光合参数与光合色素含量差异。利用光谱技术与日光诱导叶绿素荧光（Sun-induced Chlorophyll Fluorescence, SIF）技术分析了4种类型柑橘叶片的反射率光谱与SIF光谱差异。采用竞争自适应重加权采样（Competitive Adaptive Reweighted Sampling, CARS）算法结合反射率光谱筛选出特征波段,采用SIF光谱的峰值位置（687和741 nm）构建了上行（Upward, Up）和下行（Downward, Dw）SIF产量指数（Up687, Up741, Dw687, Dw741, Up687/741, Dw687/741）。进一步分别利用特征波段的反射率和SIF产量指数,结合K最邻近（K-nearest Neighbor, KNN）分类算法构建了柑橘黄龙病的诊断模型。结果表明,黄龙病菌的侵染使柑橘叶片的光合作用明显减弱,在未显症时期已经表现出来,证明了SIF技术在诊断早期HLB的优势。基于特征波段反射率的KNN模型对未显症HLB和显症HLB的诊断精度为72.7%和75.6%,健康叶片和黄斑病叶片分别为82.2%和64.1%,而基于687和741 nm波长处的上行比值SIF产量指数Up687/741构建的KNN模型对未显症HLB和显症HLB的诊断精度为84.8%和91.1%,健康和黄斑病叶片分别为88.9%和82.1%,均优于反射率光谱模型。结果证明了SIF技术用于诊断柑橘HLB的潜力,为实现柑橘HLB的田间原位、快速、早期诊断提供了可能。     

高温胁迫下水稻胚乳淀粉分支酶各同工型基因的表达特征

 以稻米品质温度敏感型的早籼稻品种浙辐49为材料,利用人工气候箱控温处理试验和实时荧光定量PCR技术,探讨了水稻发育胚乳中淀粉分支酶(starch branching enzyme, SBE)的3种主要同工型基因 (SBEⅠ、 SBEⅢ和SBEⅣ) 在不同温度处理下的相对表达量差异及动态变化特征。结果表明,高温处理对水稻胚乳中SBE基因的表达调控因其同工型的种类而异,SBEⅣ基因在高温处理下呈上调表达,而SBEⅠ和SBEⅢ基因在高温处理下的相对表达量则明显降低,表现为下调表达;与SBEⅣ等同工型相比,水稻胚乳中SBEⅠ基因对高温胁迫的表达响应相对更敏感。     

顺序注射氢化物发生-原子荧光光谱法同时测定灵芝中As和Bi

[目的]建立1种顺序注射氢化物发生-原子荧光光谱法同时测定灵芝试样中的As和Bi含量的方法。[方法]灵芝样品采用微波快速消解系统消解,用绘制的标准曲线采用原子荧光光度计测得各个样品的As和Bi含量,并考察了光电倍增管负高压、As和Bi灯电流、原子化器高度、载气流量、屏蔽气流量等因素对测定结果的影响。[结果]载流HCI的浓度为0．3mol／L,KBH。浓度为10g／L时,同时测定As和Bi的效果最佳。在最佳试验条件下,As和Bi的检出限分别为0．079和0．031μg/L,加标回收率为90．5％～104．5％,相对标准偏差小于3．4％,灵芝试样中共存的离子对As和Bi的测定没有干扰。[结论]该方法操作方便、快速,灵敏性高,适用于灵芝试样品中As和Bi含量的同时测定．具有很好的可行性和实用性。     

原子荧光法测定总砷含量不确定度评定

以圆白菜标准物质为材料,评估原子荧光法测定总砷含量的不确定度。根据不确定度分量大小可以得出,砷测定值的不确定度主要来源于测定过程中校准曲线的不确定度。该方法测定总砷含量的扩展不确定度为0.0098 mg/kg,检测结果为(0.066±0.010) mg/kg,在标准物质含量(0.062±0.014) mg/kg的范围内,表明方法的分析过程处于质控状态,结果可靠。