NaCl胁迫对海岛棉幼苗光合和荧光特性的影响

本文旨在研究盐胁迫对不同海岛棉品系幼苗生长指标、叶绿素含量、光合及叶绿素荧光参数的影响,为海岛棉耐盐材料的选育、栽培管理提供理论依据。以两份海岛棉—耐盐性强的品系越海9号和耐盐性弱的品系PS-7为材料,采用水培法,从发芽至三叶期,进行150 mM NaCl的持续胁迫,研究盐胁迫下不同海岛棉品系的生长指标、叶绿素含量、光合及荧光参数的变化。结果显示：持续NaCl胁迫降低了越海9号和PS-7的叶面积、根长、茎长、根/茎比值、叶绿素 a、叶绿素 b和叶绿素 a与b总量,提高了叶绿素a/b比值。盐胁迫促进了越海9号的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、水分利用率(WUE)、PSⅡ实际光化学量子产量(Y(Ⅱ))、光化学淬灭系数(qP)、光合电子传递相对速率(rETR)上升,PSII的最大光化学量子产量(Fv/Fm)和非光化学猝灭系数(NPQ)下降。盐胁迫导致PS-7的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用率(WUE)、PSII的最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(Y(Ⅱ))、光化学淬灭系数(qP)和光合电子传递相对速率(rETR)降低,胞间CO2浓度(Ci)和非光化学猝灭系数(NPQ)提高。PS-7的根/茎比值大于越海9号,其余指标均小于越海9号。上述结果提示,持续盐胁迫抑制了海岛棉生长指标及叶绿素等生物量积累,对耐盐性弱的品系抑制程度大于耐盐性强的品系。非气孔限制因素是导致盐胁迫下PS-7净光合速率下降的主要原因。PSⅡ实际原初光能转化效率提高是引起盐胁迫下越海9号净光合速率上升的主要原因。生长指标、叶绿素含量、光合参数、叶绿素荧光参数可作为鉴定棉花耐盐材料的生理学指标。     

外源2,4-表油菜素内酯对NaCl胁迫下燕麦幼苗光合特性的影响

为探明外源2,4-表油菜素内酯(EBR)对NaCl胁迫下燕麦光合作用的调控机理,以加燕2号、青引2号燕麦为材料,在100 mmol/L NaCl胁迫下,研究外源EBR对燕麦幼苗光合气体交换参数、荧光动力学参数、光合电子传递速率及PSⅡ光能分配情况的影响。结果表明:NaCl胁迫显著降低了燕麦幼苗的光合色素含量,抑制了PSⅡ反应中心活性,导致燕麦幼苗PSⅡ光化学效率下降,净光合速率(Pn)显著降低。和NaCl胁迫相比较,添加外源EBR后,燕麦幼苗叶片的叶绿素a(Chla)、叶绿素b(Chlb)和类胡萝卜素(Chlx·c)含量显著增加;燕麦幼苗的Pn、蒸腾速率(Tr)、气孔导度(Gs)和水分利用效率(WUE)显著升高,胞间CO_2浓度(Ci)显著降低,最大荧光(Fm)、光化学淬灭系数(qP)、PSⅡ实际光合效率(ФPSⅡ)、PSⅡ潜在活性(Fv/Fo)、PSⅡ原初光能转化效率(Fv/Fm)、天线色素转化效率(Fv′/Fm′)、表观光合电子传递速率(ETR)及PSⅡ光化学反应能(P)显著升高,初始荧光(Fo)、非光化学淬灭系数(NPQ)及反应中心耗散能(E)、天线耗散能(D)显著降低。综上所述,外源EBR能够显著提高NaCl胁迫下燕麦幼苗PSⅡ反应中心的实际光化学效率,有效缓解NaCl胁迫对燕麦幼苗所产生的光抑制和PSⅡ反应中心损伤程度,提高燕麦幼苗的碳同化效率和光合能力,说明外源BRs对盐胁迫下燕麦光合作用起到正向调控作用,能够有效缓解盐胁迫对燕麦幼苗所造成的伤害。     

水分和高温复合胁迫对水稻幼苗光合生理特性的影响

以水稻“迁星1号”幼苗为材料,进行水分(PEG6000浓度分别为0%,10%,15%,20%)和高温(35,40℃)双重胁迫处理,研究水分和高温复合胁迫对水稻幼苗光合生理特性的影响,为探索调控植物光合生理措施、规避高温干旱复合逆境伤害提供理论依据。结果表明,轻度水分胁迫(PEG6000浓度为10%)下,35℃高温处理的水稻幼苗净光合速率(Pn)、气孔导度(gs)胞间CO2浓度(Ci)、总叶绿素(Chla+b)含量、叶绿素a/b(Chla/b)、初始荧光产量(Fo)、最大荧光产量(Fm)和PS II最大光化学量子产量(Fv/Fm)与对照相比无显著变化;40℃高温处理的水稻幼苗在3种水分胁迫下,Pn,gs,Ci,Chla+b,Chla/b,Fm和Fv/Fm显著低于对照,Fo显著高于对照。说明35℃高温处理水稻幼苗光合生理特性在轻度水分胁迫下未受到明显抑制,表现出对水分胁迫具有一定的适应性;随着胁迫温度的升高,40℃高温处理的水稻幼苗对水分胁迫的适应性显著下降,其光合生理特性受到明显抑制。     

NaCl胁迫对丁香‘瓷蓝’光合作用及叶绿素荧光的影响

为研究NaCl胁迫对丁香‘瓷蓝’光合作用的影响,以‘瓷蓝’的一年生扦插苗为试材,对不同浓度NaCl胁迫下‘瓷蓝’的叶绿素含量、光合特性及叶绿素荧光参数等进行研究。结果表明:盐胁迫使得光合性能降低,并且随着盐浓度的增加,叶绿素含量、光化学猝灭系数(q P)、PSⅡ的实际光化学效率(ΦPSⅡ)和PSⅡ最大光化学量子产量(Fv/Fm)呈下降趋势。非光化学猝灭系数(NPQ)呈先增加后下降趋势。光合速率下降的主要原因为气孔限制。‘瓷蓝’的耐盐范围在0.4%以下,在盐浓度低于0.4%时会通过提高非光化学猝灭系数(NPQ)来抵抗胁迫造成的伤害,当盐浓度高于0.4%时其光合机构受损严重,产生严重光抑制。     

外源CaCl2对盐胁迫下苹果砧木T337生理特性的影响

为探究不同浓度外源喷施CaCl_2对盐胁迫下苹果幼苗生理特性的影响,以二年生T337实生苗为试材,通过盆栽试验法,设置100 mmol/L NaCl(T1)和100 mmol/L NaCl+4种不同浓度CaCl_2(5.0(T2),7.5(T3),10.0(T4),12.5 mmol/L(T5))处理,以去离子水浇灌为对照(CK)。测定各处理组的叶绿素含量、光合与荧光参数、抗氧化酶活性及渗透调节物质含量,并对其进行相关性和主成分分析。结果表明,随胁迫时间延长,T337叶片的过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)呈先升后降趋势,丙二醛(MDA)、胞间CO_2浓度(Ci)、脯氨酸(Pro)和相对电导率(REC)呈不断上升趋势,初始荧光(F0)、PSⅡ最大光能转化率(Fv/Fm)、气孔导度(Gs)和蒸腾速率(Tr)呈下降趋势;相比CK和T1,外源CaCl_2处理后T337叶片各指标的变幅均减小,存在明显浓度效应。其中,T4(10 mmol/L)处理下相对叶绿素含量(SPAD)、Pn、Tr、POD、F0及SOD降幅最小,显著高于其他处理组;MDA、REC和Ci升幅最小,显著高于CK,低于其他处理组。14个指标相关性分析表明,Pn与CAT、Tr、Gs、F0、Fv/Fm、ETR、SPAD、SOD和POD呈正相关,与Pro、MDA、Ci、REC呈负相关。将盐胁迫处理后相关的14个指标进行主成分分析,提取特征值大于1的2个主成分,其特征值分别为11.190,2.295;第一、二主成分方差贡献率依次为79.930%,16.394%,累计方差贡献率达到96.324%,符合分析要求。依据主成分得分排序,外源CaCl_2对T337盐胁迫缓解能力由高到低为T4T3T2T5。因此,10 mmol/L的CaCl_2能更好地改善盐胁迫下T337砧木叶片的光合荧光特性、提高抗氧化酶系统和渗透调节能力、增强生物膜稳定性和通透性达到缓解盐胁迫的效应。     

基于光合和荧光参数探讨不同水稻品种苗期耐寒性差异

发掘苗期耐寒种质资源,培育耐寒品种是减少冷害影响的有效手段.以30份水稻品种为研究对象,测定水稻幼苗在人工低温胁迫条件下叶绿素含量(SPAD值)、光能转化效率(Fv/Fm)值及PSⅡ潜在活性(Fv/F0)值的变化.结果表明,低温胁迫后,各供试材料幼苗叶片中SPAD值、Fv/Fm值以及Fv/F0值均出现不同程度的下降.粳...     

不同玉米品种对干旱胁迫的响应

采用盆栽试验,研究不同梯度水分胁迫对不同时期的玉米品种先玉335,陕单902的叶绿素荧光参数、光合性状和渗透调节物质的影响。结果表明,水分胁迫导致玉米叶片光合能力下降,初始荧光Fo,脯氨酸含量上升,反应中心PSⅡ的潜在活性Fv/Fo,PSⅡ原初光能转换效率Fv/Fm,PSⅡ反应中心的激发能捕获效率Fv′/Fm′受到抑制,水分利用效率WUE和可溶性蛋白的含量下降。通过分析得出,新玉米品种先玉335在苗期对水分胁迫有良好抵抗能力。     

玉米叶片光合生理与抗旱性关系研究

在水分胁迫条件下,对玉米叶片净光舍速率、叶绿素含量及叶绿素荧光参数的变化进行了研究.结果表明:玉米叶片净光合速率(Pn)、叶绿素a(Chl a)、叶绿素b(Chl b)、总叶绿素含量(Chl)、叶绿素a/b比值(Chl a/b)、最大荧光(Fm)和PsⅡ光化学效率(Fv/Fm)比对照均有所下降,基础荧光(Fo)增加;Pn和Ctd a/b比值占对照百分率与品种抗旱性呈极显著正相关(r=0.8807**,P<0.01;r=0.8804**,P<0.01),Fo占对照百分率与品种抗旱性则呈显著负相关(r=-0.764 0*,P<0.05),Fm和Fv/Fm占对照百分率与品种抗旱性则呈显著正相关(r=0.711 6*,P<0.05;r=0.772 3*,P<0.05).因此,净光合速率、叶绿素a/b比值、Fo、Fin和Fv/,m可以用来评定不同玉米品种的抗旱性.     

干旱胁迫下陆地棉光合叶绿素荧光参数与产量品质间的关联性分析

本研究在控制水肥条件下,以不同抗旱性的14份陆地棉为材料,通过测定现蕾期叶片的SPAD值、光合叶绿素荧光参数、吐絮期产量、分析光合叶绿素荧光参数与产量品质间的相关性,筛选出与抗旱性密切相关的指标.结果 表明,陆地棉18k0205的蒸腾速率(Tr)、气孔导度(Gs)、光合速率(Pn)、光系统Ⅱ有效量子产量ΦPSⅡ和田间产量均高于其他陆地棉材料,而18K0319的纤维长度和断裂比强度均高于其他材料,这两个材料可作为优异抗旱种质资源进行育种实践.14份材料的光合叶绿素荧光参数与产量品质间的相关性分析表明,净光合速率(Pn)与衣分呈显著负相关,水分利用效率(WUE)与纤维长度呈显著正相关,与马克隆值呈显著负相关.光系统Ⅱ的有效量子产量ΦPSⅡ与衣分呈显著负相关.灰色关联度分析表明,产量与Fv/Fm、SPAD、单铃重紧密关联,关联系数0.85以上;纤维长度与WUE、Fv/Fm、Fm、SPAD紧密关联,关联系数0.90以上;衣分与SPAD、单铃重、Fv/Fm紧密关联,关联系数0.88以上;纤维断裂比强度与SPAD、qP、ΦPSⅡ紧密关联,关联系数0.89以上;马克隆值与FV/Fm、ΦPSⅡ、Gi紧密关联,关联系数0.87以上.研究结果表明陆地棉产量及纤维品质性状与Fv/Fm、SPAD、单铃重、ΦPSⅡ等重要性状紧密关联,上述研究结果为棉花抗旱种质资源筛选和鉴定提供一定的参考依据.     

盐胁迫对水稻叶片光合作用和叶绿素荧光特性的影响

以一个耐盐水稻品种和一个盐敏感水稻品种为材料,从孕穗初期开始进行NaCl胁迫(浓度分别为0,40,80,120mmo1/L ),研究盐胁迫下水稻叶片光合气体交换参数和叶绿素荧光参数的变化。结果表明:盐胁迫使两个水稻品种叶片叶绿素含量、净光合速率(Pn)、气孔导度(Cs)和表观叶肉导度(AMC)均显著下降,盐敏感品种各指标随盐浓度的增加下降更显著;耐盐品种的胞间CO2浓度(Ci)和气孔限制值(Ls)在各浓度盐胁迫下变化均未达到显著差异,盐敏感品种在低盐浓度(40mmo1/L)胁迫下,Ci和Ls变化不显著,在高盐浓度(80mmo1/L和120mmo1/L)下,Ci显著下降,且Ls显著上升;盐胁迫下两个品种的Fv/F0, Fv’/Fm’,ΦPSII,ETR、光化学碎灭(qP)下降,非光化学碎灭(qN)升高,盐敏感品种随盐浓度的增加各指标变化更显著。由本试验可知,盐胁迫下水稻品种光合速率的下降是由非气孔限制因素引起的,而盐敏感品种在高浓度盐胁迫下还增加了气孔限制因素。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.