用露点法和湿度法测定叶片水势及其组分

本文讨论了样品水势差异对叶室平衡时间和热电偶冷却时间的影响;比较了湿度法和露点法的测定结果,活体测定与离体测定的结果以及两种渗透势测定方法的结果;并用离体法测定了大麦在NaCl胁迫下叶片ψw,ψs和ψp的动态变化;用活体法测定了小麦和蚕豆在大田条件下叶片ψw、ψs和ψp的昼夜变化。     

原位胶原酶循环灌注法分离猪肝细胞

本文建立了原位胶原酶循环灌注分离猪肝细胞方法并与离体两步胶原酶灌注法进行了比较。猪门静脉和下腔静脉分剐插管,先用D-Hanks液灌注,再采用自制的循环灌流装置进行胶原酶循环原位灌注分离猪肝细胞,分离后的肝细胞以5×105/ml培养,观察分离和培养7d的肝细胞产量、活率、蛋白质合成功能、葡萄糖合成功能和LDH含量。同时测定离体组的上述指标。研究结果表明采用原位胶原酶循环灌注法每克肝组织分离获得的肝细胞总量为5.1×107,肝细胞活率98.6％,培养7d肝细胞活率89.5％。肝细胞的蛋白质合成功能在培养7d中保持稳定;葡萄糖合成功能从1d时1.05±0.15nmol/cell下降到3d时0.74±0.09nmol/cell;LDH含量在3d较高。原位胶原酶循环灌注法分离的猪肝细胞总量、活率高于离体法;蛋白质合成功能和葡萄糖合成功能强于离体法。因此,原位胶原酶循环灌注分离猪肝细胞方法可获得大量高活率和良好功能的猪肝细胞。     

香蕉枯萎镰刀菌致病性快速测定方法的建立

建立致病性变异突变体库是研究香蕉枯萎镰刀菌致病机理的有效方法,此方法需要对大量突变体进行致病性测定,经典的根部接种测定方法耗时长达40 d,工作量十分巨大。因此,建立一种简便快速的致病性测定方法是高效建立香蕉枯萎病菌致病性变异突变体库的关键。本研究以香蕉巴西蕉和粉蕉叶片为材料,采用香蕉离体叶片分别接种香蕉枯萎病菌1号小种、4号小种、致病性丧失突变体、致病性严重减弱突变体,分别置于20℃、25℃、30℃、35℃、37℃条件下进行保湿培养3 d、5 d、7 d,观察发病情况,测定病斑大小。并通过根部接种法对离体叶片接种法的结果进行验证。结果表明,离体叶片测定法和根部接种法测定的结果一致,最佳致病温度30℃。从而建立了一种简便快速的香蕉枯萎病突变体致病性测定方法(离体叶片接种法)。运用该法在适宜的条件下可以准确、可靠、快速和简便测出香蕉枯萎病菌致病性,大大提高了突变体致病性测定筛选的效率。     

高大乔木原位与离体叶片气体交换特征的比较——以三种环境下的青冈栎(Cyclobalanopsis glauca)为例

乔木由于个体高大,采用便携式仪器(如Li-6400)进行气体交换测定时的采样存在很多困难.研究了岩溶区、非岩溶区和盆栽等3种生境条件下的青冈栎植物叶片离体后的气体交换参数衰变特性并与活体状态进行比较,以确定叶片离体后仍能代表原位状态的最佳测定时间.叶片离开母体后,气孔短时内略微变大,然后逐渐关闭.不同条件下气孔的这种变化差异较大;蒸腾作用与气孔导度极显著线性相关,蒸腾作用受到气孔关闭的影响明显.离体叶片的蒸腾作用的大小与叶片的温度高低相一致.光合效率与气孔导度也呈显著相关,但相关程度较前者弱.不同温度条件下离体叶片的气体交换特征是不一样的,岩溶区高温加速了叶片的蒸腾速率,减少叶片组织自由含水量,导致水分胁迫的提前到来.温度越低离体叶片光合作用的衰减过程越慢.离体叶片的气体交换参数的在一定时间范围内的可靠性取决于叶片温度.在温度较低的时候(如20℃),离体叶片的可靠性20min以上,温度比较高(非岩溶区,温度约为32℃))的情况下,只有10min左右,而温度很高(岩溶区,叶温≥32℃)的情况下,这种可靠时间只有3～6min.     

拟南芥连体和离体叶片光合作用的光响应

测定出 2 5 0 μmol·m-2 ·s-1光强下培养的整株拟南芥连体叶片的光合作用在光强为 80 0 μmol·m-2 ·s-1左右达到光饱和 ,其离体叶片光合作用对光强响应的结果与此类似。自然条件下生长的珊瑚树连体与离体叶片光合作用均在光强约为 10 0 0 μmol·m-2 ·s-1下达到饱和 ,这验证所测得的拟南芥连体和离体叶片光合作用光响应的结果是正确的     

东北主要树种光合作用可行的离体测定方法

树木光合作用的测定常因植株高大而难以开展, 其中离体测定是解决途径之一。但离体测定的方法及其可靠性因树种而异。选取东北东部温带森林中特性各异的7种主要树种: 针叶树(红松(Pinus koraiensis)、长白落叶松(Larix olgensis))、散孔材(白桦(Betula platyphylla)、胡桃楸(Juglans mandshurica))和环孔材(水曲柳(Fraxinus mandshurica)、黄榆(Ulmus macrocarpa)、蒙古栎(Quercus mongolica)), 首先采用光合速率恢复到光合诱导前稳定值90%的时间(T₉₀)长短和叶片蒸腾速率(E)的大小评估离体叶片水分供应状况及其光合活力, 以此确定较优的离体测定方案; 同时, 观测离体叶片的光合活力稳定时间; 最后通过比较原位测定和采用所确定的较优离体方案测定的各树种叶片气体交换参数, 论证采用离体测定光合作用的可靠性。结果表明: 除蒙古栎外的6个树种的离体叶片均具有较高、较稳定的水分供应和光合活力。离体枝条或复叶插入水中, 环剥去除切口处3 cm左右的韧皮部和剩余叶片的方法, 是这6个温带树种叶片光合能力的较优离体测定方法。6个树种叶片的T₉₀受树木特性的影响而差异显著(p < 0.05), 其中环孔材树种的T₉₀显著高于散孔材和针叶树种。6个树种离体叶片在1 h内均有较高、较稳定的水分供应和光合活力。在此期间离体所测得的绝大多数叶片的气体交换参数与其原位测定值之间的差异不显著。该研究提出了可行的树木叶片光合作用的离体测定方案, 适用于蒙古栎以外的其他6个温带树种。     

凹凸不平的植物叶片表皮制片方法的观察比较

以麦冬和土麦冬为实验材料,采用指甲油印迹法、次氯酸钠离析法、三氧化铬离析法和常规扫描电镜制样法对叶片表皮进行制样,光学显微镜和电子显微镜现察比较不同制样方法的效果.结果表明,指甲油印迹法对凹凸不平的叶片表皮观察效果较差;次氯酸钠离析法可以获得叶片表皮细胞形态的特征,但对凹凸明显的气孔器轮廓无法获得理想的结果;常规扫描电镜可观察叶片表皮的细微形态,但对角质层较厚的叶片,叶片表皮细胞轮廓很难区分;三氧化铬离析法获得的角质层,是一种理想的观察角质层较厚的叶片表皮微形态的方法,可以清晰显示叶片表皮微形态.     

三种抗生素对西花蓟马存活率及肠道可培养细菌的影响

为阐明抗生素对西花蓟马的作用,选用氨苄青霉素(AMP)、氯霉素(CAP)和硫酸链霉素(SM)等3种抗生素分别采用薄膜饲喂法和叶片浸渍法处理西花蓟马,研究3种抗生素对西花蓟马死亡率及对肠道可培养细菌的影响。结果表明抗生素对西花蓟马的死亡率有明显的影响,随着浓度的增加和处理时间的延长死亡率升高,在薄膜饲喂法和叶片浸渍法处理下,西花蓟马均是在3种抗生素浓度为50.00 mg/mL处理72 h时死亡率最大,薄膜饲喂法对西花蓟马死亡率的影响高于叶片浸渍法。在2种饲喂方式下,25.00 mg/mL氨苄青霉素和50.00 mg/mL硫酸链霉素处理72 h后对西花蓟马肠道内可培养细菌的去除效果最好;浓度为50.00 mg/mL氯霉素在薄膜饲喂法中处理24 h后对西花蓟马肠道细菌去除效果最好,但叶片浸渍法没有明显的作用。结果说明,西花蓟马死亡率及肠道细菌的去除效果与抗生素种类、浓度和处理时间相关,也与处理方法有关。     

打孔称重法与复印称重法和长宽校正法测定水稻叶面积的方法比较

打孔称重法是基于相近叶位叶片的比叶重（单位面积叶片重量）相对恒定的原理,通过测定采样区植物叶片干重和少量叶片比叶重计算叶面积和叶面积指数的方法。比较试验结果表明：打孔称重法与长宽校正法和复印称重法测定的水稻叶面积呈极显著相关;打孔称重法和复印称重法所测定的叶面积指数平均值经统计检验差异不显著。2种方法均能很好地袁征不同处理间叶面积指数的差异。     

抗肿瘤药物筛选中MTT法和SRB法的比较

在抗肿瘤药物的体外筛选中 ,MTT法和 SRB法是常用的两种方法。我们用MTT法和 SRB法分别测定 3种已知植物抗癌药对 2 2株人肿瘤细胞的抗癌活性 ,对这两种方法进行了详细的比较。通过分析两种方法测出的细胞存活率 ( T/ C)的差异分布和相关系数以及 IC50 的二变量分布 ,比较了两种方法测定结果的异同 ;通过两种方法重复测定 3种药物对 7株人癌细胞的抗癌活性 ,比较了两种方法的重复性 ;通过分析两种方法测定结果 T/ C值随时间变化的程度 ,比较了两种方法测定结果的稳定性。实验结果表明 :MTT法和 SRB法的相关性较好 ,都可用于抗肿瘤药物的体外筛选 ,SRB法更适合于大规模筛选 ,3种抗癌药物的测定结果与临床资料基本一致。     

Impact of derived global weather data on simulated crop yields

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long‐term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water‐limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well‐maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26–72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA‐POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12–19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location‐specific observed daily weather databases combined with an appropriate upscaling method.     

三色(Bougainvillea peruviana‘Thimma’)在转录水平的甜菜色素和类黄酮积累比较

Bougainvillea peruviana‘Thimma’属于三角梅属,该属植物积累甜菜色素而不是像绝大多数高等植物一样积累花青素。该材料特征同株出现3种颜色：白色、洋红色和白/洋红相间。本研究首次使用3种花色特征的花序（红色Yp、混合色的Ym、白色Yw）作为研究材料进行高通量测序。并通过real-time PCR方法对探测到的花色代谢基因进行验证。共获得平均长度为616 bp的73 325条基因。3种材料的差异显示基因（DEGs）中有327个被注释到甜菜色素合成基因,308个被注释到类黄酮合成基因,466个被注释到花青素合成基因。我们选出8个基因：4个甜菜色素合成基因（PPO,CYP76AD1,cDOPA-5-GT,DODA）和4个花青素合成基因（FLS,DFR,LDOX,3-GT）进行验证。其中,4个甜菜色素合成基因在3种花色材料中的表达较好的正相关于甜菜色素含量。花青素合成途径末端的3个基因（DFR,LDOX,3-GT）在B.peruviana中首次被验证。real-time PCR的验证结果很好的吻合转录组测序的结果。同时,B.peruviana也提供了一个很好的三角梅属植物的生理、生化和分子生物学研究的工具,有效的摒除其他生物学干扰。     

Assessment of salinity indices to identify Iranian wheat varieties using an artificial neural network

In arid and semi‐arid regions of the world, including Iran, soil salinity is one of the major abiotic stresses. One of the ways to achieve high performance in these areas is to use salt‐tolerant varieties of wheat. Iran is known as one of the places where the D‐genome originated and evolved. In order to evaluate the salt tolerance of Iranian genotypes based on the eight indices using analysis of variance, regression and an artificial neural network (ANN), 41 Iranian wheat varieties (Trticum aestivum L.) were planted in a randomised complete block design with three replications under two saline irrigation conditions, 0.631 and 11.8 dS m^?1, in Kerman, Iran. Significant differences between the varieties were observed, and the significant two‐way interaction of environment × varieties in combined analysis and non‐significant correlation, 0.07, between the yield in two environments (yield in non‐stress conditions, Yp, and yield in stress conditions, Ys) indicates the existence of genetic variation among varieties and the different responses of the varieties in both the environments. The indices of tolerance, geometric mean product (GMP), mean product (MP), harmonic mean (HM) and stress tolerance index (STI) were calculated based on grain yield evidence of positive significant correlation with Yp and Ys. Based on the ANN results, yield stability index (YSI), MP, GMP and STI were the best indices to predict salinity‐tolerant varieties. The varieties selected based on these indices, such as Bolani, Sistan, Ofogh, Pishtaz, Karchia and Arg, produced high yield in both the environments. These results show that bread wheat originating from Iran has salt tolerance potential and can also be used in studies related to salinity tolerance mechanisms.     

Effect of the rol genes from Agrobacterium rhizogenes on polyamine metabolism in tobacco roots

Plants of the mangrove species Pelliciera rhizophoreae and Avicennia germinans, exhibit pronounced oscillations in stomatal aperture under certain climatic conditions. During these oscillations, changes in transpirational water loss were closely followed by those in leaf water potential (ψ1) as indicated by continuous monitoring with an in situ dewpoint hygrometer. With this instrument, it was possible to measure dynamic changes in ψ1 for several days under constant conditions. Subsequently, the leaf was detached from the shoot and a pressure-volume (PV) curve was established by repeatedly weighing the leaf, still attached to the hygrometer during short interruptions of the water potential recordings. The pressure-volume relationship was then used to derive other water relations parameters from these water potential data. Thus, the procedure described herein allows a continuous analysis of the relevant components of bulk leaf water relations. Oscillations in water potential were also measured with single leaves using a pressure chamber. Water relations data obtained with these two different methods were in good agreement. In addition, osmotic potentials derived from the PV-analysis were well within the range of those determined cryoscopically using extracted cell sap.     

Biodegradation of methyl parathion and p-nitrophenol by a newly isolated Agrobacterium sp. strain Yw12

Strain Yw12, isolated from activated sludge, could completely degrade and utilize methyl parathion as the sole carbon, phosphorus and energy sources for growth in the basic salt media. It could also completely degrade and utilize p-nitrophenol as the sole carbon and energy sources for growth in the minimal salt media. Phenotypic features, physiological and biochemical characteristics, and phylogenetic analysis of 16S rRNA sequence showed that this strain belongs to the genus of Agrobacterium sp. Response surface methodology was used to optimize degradation conditions. Under its optimal degradation conditions, 50 mg l⁻¹ MP was completely degraded within 2 h by strain Yw12 and the degradation product PNP was also completely degraded within 6 h. Furthermore, strain Yw12 could also degrade phoxim, methamidophos, chlorpyrifos, carbofuran, deltamethrin and atrazine when provided as the sole carbon and energy sources. Enzymatic analysis revealed that the MP degrading enzyme of strain Yw12 is an intracellular enzyme and is expressed constitutively. These results indicated that strain Yw12 might be used as a potential and effective organophosphate pesticides degrader for bioremediation of contaminated sites.     

Relative order determination of four Yp cosmids on metaphase and interphase chromosomes by two-color competitive in situ hybridization

Summary Two-color competitive in situ hybridization was used to cytogenetically order four Yp cosmid probes, located in the pseudo-autosomal and TDF regions. The probes were hybridized by pairs to metaphase and interphase chromosomes. On metaphase chromosomes, determination of order between sequences separated by 3 Mb from each other was possible on a statistical basis, whereas the relative position of sequences 0.6Mb apart could not be determined. On interphase chromosomes the complete order between sequences separated by 0.6– 6Mb was obtained rapidly by measuring the distances between two cosmid spots of every cosmid pair used in 28 to 60 nuclei. Results demonstrate the potential power of fluorescent in situ hybridization at interphase for high resolution cosmid mapping.     

The isoperoxidase pattern changes and the pigment changes of pedilanthus tithymaloides L. Variegatus calli as a result of sucrose concentration and phytoregulator content of the culture medium and daily temperature differences

In vitro, stem slices growing in calli exhibited the same pigment changes as the previously described ones with developing leaves. These changes were controlled by daily temperature differences, but they were also modulated by the sugar type or the sucrose concentration of the culture medium. The electrophoretic isoperoxidase patterns of the calli showed quantitative and qualitative changes during pigment evolution. Each of the three peroxidasic band groups which was correlated in situ with a characteristic pigment expression in the leaves was also correlated in vitro with a similar pigmentation in the calli. Calli cultured on media supplemented only with naphtalene-acetic acid as phytoregulator exhibited a brown pigmentation and produced the fast migrating isoperoxidase group. Calli grown in the presence of 6-benzylaminopurine only had no pigmentation and expressed the slow migrating isoperoxidase group. The calli grown without any phytoregulator were green coloured and expressed the medium migrating isoperoxidase group.     

Deletion mapping of the testis determining locus with DNA probes in 46,XX males and in 46,XY and 46,X,dic(Y) females.

Eleven Y-specific DNA probes hybridizing with DNA from one or more 46,XX males were isolated from a recombinant phage DNA library constructed from flow sorted human Y chromosomes. Two probes hybridized with DNA from nine out of eleven, i.e. greater than 80% of these 46,XX males. The relative frequency of hybridization of the probes in the 46,XX males and in a 46,X,dic(Y) female, together with in situ hybridization data, allowed mapping of the probes on Yp in relation to a putative testis determining locus. Several of those probes were also absent in a 46,XY female, further refining a model for ordering the probes on Yp. The DNA of one XX male hybridized both with probes from Yp and probes from proximal Yq (excluding the pericentral region). This suggests that complex translocations may occur into the DNA of 46,XX males that involve not only parts of Yp but also parts of Yq.     

Isoprene synthase activity and its relation to isoprene emission in Quercus robur L. leaves

Pedunculate oak ( Quercus robur L.) is known as a strong isoprene (2-methyl-1,3-butadiene) emitter. Diurnal changes in isoprene emission were determined by branch enclosure measurements. In contrast to the diurnal cycle in emission rates, specific isoprene synthase activity in the leaves remained unchanged. Based on in vitro enzyme activity and its temperature dependency, an isoprene synthesis capacity at specific leaf temperatures was calculated. The comparison of these 'leaf temperature-dependent enzyme capacities' and the measured emission rates revealed that the enzyme activity of isoprene synthase is comparable to the observed isoprene emission rates. In addition, variation in the isoprene synthase activity of the leaves due to changes in light intensity during leaf development was investigated. A 50% reduction of light intensity by shading of single branches reduced isoprene synthase activity by ≈ 60% compared with full sunlight. The calculation of isoprene synthesis capacities based on enzymatic data obtained under optimum reaction conditions, corrected for actual leaf temperature and related to leaf surface area, provides a sound basis for predicting the isoprene emission potential of plants.