氮素水平对不同品种茶树光合及叶绿素荧光特性的影响

为探明氮素水平对不同品种茶树的光合系统的影响机制,以‘福鼎大白茶’、‘保靖黄金茶1号’、‘白毫早’两年生茶苗为材料,设置不施氮N_0(0g)、低氮N_1(11g)、中氮N_2(22g)和高氮N_3(33g)4个氮素[(NH_4)_2SO_4]水平的盆栽实验,研究了铵态氮对3个品种茶树的生长势、叶片叶绿素含量、光合参数与叶绿素荧光参数的影响。结果表明:(1)施氮处理能够显著促进茶树的生长,提高茶树叶片叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr),降低胞间CO_2浓度(Ci),并以N_2处理最好,但水分利用率(WUE)在3个品种茶树间表现不同。(2)在N_2处理下,3个茶树品种的叶片光系统Ⅱ(PSⅡ)暗适应下的最大光化学效率(F_v/F_m)、光化学猝灭系数(qP)、PSⅡ的相对电子传递速率(rETR)亦增加最大,非光化学淬灭系数(NPQ)降低。(3)茶树叶片叶绿素含量与光合参数间存在着一定的联系,并且具有品种特异性。研究发现,适量施氮能够显著增加茶树叶绿素含量、气孔导度、光合活性,从而使得各品种茶树净光合速率增加;氮素水平对各茶树品种的光合及荧光特性影响存在差异,水分利用率亦具有品种特异性;生产中应综合叶绿素含量、光合作用参数、叶绿素荧光参数,可快速、直观地评价不同品种茶树对氮素营养的内在需求,为茶园施肥管理提供指导。     

Influence of Water Stress on Water Relations, Photosynthetic Parameters and Nitrogen Metabolism of Moth Bean Genotypes

Effects of water stress at pre-flowering stage were studied in three genotypes (RMO-40, Maru moth and CZM-32 E) of moth bean [Vigna aconitifolia (Jacq.) Marechal]. Increasing water stress progressively decreased plant water potential, leaf area, net photosynthetic rate, starch and soluble protein contents and nitrate reductase activity while contents of reducing sugars, total soluble sugar, free amino acids and free proline progressively increased. Significant genotypic differences were observed and genotype CZM-32-E displayed a better drought tolerance than other genotypes.     

茶丽纹象甲为害诱导的茶树防御反应分析

基于转录组测序,获得了茶树新梢叶片被茶丽纹象甲为害前后的差异基因表达谱,并从信号监测与转导、转录因子、次生代谢物生成等方面分析了相关基因的表达变化情况,为进一步研究茶丽纹象甲为害诱导的茶树防御机制奠定基础。结果表明:(1)茶丽纹象甲为害茶树新梢叶片后共检测到显著上调表达基因309个,显著下调表达基因297个,这些显著差异表达基因共分成23类。(2)检测到信号监测与转导过程中合计17个单基因上调表达2.0～2.8倍,包括富含亮氨酸重复序列的类受体蛋白激酶基因、促分裂原活化蛋白激酶级联信号系统蛋白激酶基因、茉莉酸信号通路基因、钙离子信号基因、水杨酸代谢通路基因;检测到21个转录因子单基因上调表达1.8～2.8倍,包括bHLH、WRKY、bZIP、MYB、UAF等转录因子;检测到苯丙类、类黄酮及萜类物质代谢过程中合计8个单基因上调表达2.1～2.5倍,包括苯丙酮酸互变异构酶基因、肉桂酰辅酶A还原酶基因、二氢黄酮醇还原酶基因、花色素还原酶基因、法尼基二磷酸合成酶基因、法尼醇脱氢酶基因。研究认为,茶丽纹象甲为害诱导信号转导、转录因子及次生代谢过程中的基因增量表达以机械损伤作用为主,昆虫口腔分泌物对这些基因的诱导表达具有协同促进作用。     

Effect of Benzylaminopurine on Rehydration of Bean Plants after Water Stress

The possibility of improving the recovery of plant photosynthesis after water stress by cytokinin-induced stimulation of stomatal opening or delay of leaf senescence was tested. The 6-benzylaminopurine (BAP) in concentrations 1 and 10 M was applied to the substrate (sand + nutrient solution) or sprayed on primary leaves of 14-d-old Phaseolus vulgaris L. plants sufficiently supplied with water or water-stressed for 4 d. The later ones having relative water content decreased to 69 % were fully rehydrated during the following three days. Parameters of photosynthesis and water relations were measured in primary leaves of 7-, 10-, 14-, and 17-d-old plants. Application of 1 M BAP slightly delayed leaf senescence: in 17-d-old control plants, net photosynthetic rate (P_N) and chlorophyll (Chl) content, and when sprayed on leaves also some of Chl a fluorescence kinetic parameters of BAP-treated leaves were slightly higher than those of untreated leaves. Both types of application of 1 M BAP slightly improved recovery of plants during rehydration after water stress in terms of increased g_ad, g_ab and P_N, i.e., parameters which were markedly decreased by mild water stress. However, contents of Chl a, Chl b and carotenoids and parameters of Chl a fluorescence kinetic were not markedly affected by mild water stress and after rehydration were not stimulated by 1 M BAP. 10 M BAP had mostly negative effects on the parameters measured.     

茶树CPP转录因子家族的全基因组鉴定及分析

CPP(cysteine-rich polycomb-like protein)转录因子广泛存在于动植物中,是一类成员数目较少的转录因子家族,在调控植物生长发育和响应非生物胁迫中起重要作用。该研究通过对茶树基因组系统的鉴定,获得10个CsCPP转录因子均具有典型的CXC结构域。系统发育分析将CsCPP家族成员分为4类(A^D),且大部分成员与葡萄在进化关系上更为接近。A类和C类成员的CXC结构域分布在蛋白序列的N端,而B类和D类成员分布在C端。茶树组织表达分析表明,CsCPP转录因子在生长活跃的顶芽和嫩叶中普遍高表达,不同组织的表达水平排序为:顶芽和嫩叶>根和茎>成熟叶和果>老叶和花。启动子分析发现了CsCPP家族成员的启动子区域存在大量的ABA和干旱响应元件;干旱处理下,6个CsCPP成员的表达水平均有不同程度上调,其中4个成员在ABA处理后表达迅速上调,表明CsCPP转录因子可能在ABA介导的干旱胁迫响应中起正调控作用;低温处理下,大部分CsCPP成员的表达均有轻微下调,而CsCPP 2和CsCPP 6的表达水平在6 h达到顶峰,表达量均超过2倍。研究结果为进一步发掘茶树CPP转录因子家族的功能奠定了基础。     

不同浓度氟对茶树幼苗叶片叶绿素荧光特性的影响

为探讨氟对茶树[Camellia sinensis(L.)O.Kuntze]叶片叶绿素荧光特性的影响,采用盆栽沙培法,用不同浓度的Na F溶液处理6周,对茶树叶片的叶绿素荧光特性进行研究。结果表明,用600 mg L–1的氟处理,茶苗叶片的OJIP曲线O相呈小幅度上升,P相下降得非常明显,IP相显著下降,出现清晰的L点(150μs)和K点(300μs);经过氟处理的茶苗叶片I点、J点的相对可变荧光和耗散能增加;荧光参数RC/CSo、ETo/ABS、PIabs、PIcs等明显下降,而DIo/RC、DIo/CSo和DIo/ABS等参数大幅度增加;叶片氟含量与ETo/TRo、REo/ABS、PICS呈负相关,与DIo/RC呈正相关。因此,氟胁迫处理削弱了茶树叶片的光合电子传递能力,影响了光合机构的作用,同时叶片以增加自身热耗散来防止受到光抑制和光破坏。     

Amelioration of Negative Effect of Water Stress in Cassia Angustifolia by Benzyladenine and/or Ascorbic Acid

The effect of benzyladenine (BA) and ascorbic acid (AA) on relative water content, proline accumulation, net photosynthetic rate (P_N), chlorophyll (Chl) content and nitrate reductase (NR) activity, under sufficient water supply and moisture stress was studied in senna (Cassia angustifolia Vahl.) at seedling, vegetative, flowering and pod formation stages. AA treatment resulted in a higher accumulation of proline at all the stages of growth. Both BA and AA enhanced P_N, Chl content and NR activity, and ameliorate the negative effect of water stress.     

茶树苯丙素类/苯环型挥发性物质的生物合成和胁迫响应的研究进展

茶(Camellia sinensis)的挥发性物质不仅会影响茶香的品质,也会在茶树中发挥重要的生态学功能。除了萜类和脂肪酸衍生类挥发性物质外,苯丙素类/苯环型挥发性物质(volatile phenylpropanoids/benzenoids, VPBs)也同样具有这些方面的功能。正因为具有这些功能,茶树中的VPBs也受到了人们越来越多的重视和研究。对近年来茶中一些具代表性VPBs的研究进展进行了综述,包括2-苯乙醇、苯乙醛等VPBs的生物合成及其对光胁迫的响应;1-苯乙醇和苯乙酮的生物合成途径及其对昆虫胁迫的响应;吲哚的生物合成及其在温度和机械损伤胁迫下的响应机制。此外,也探讨了VPBs中一些非传统的生物合成途径,以及这些途径在某些胁迫条件下的响应机制。     

茶树CsGME1基因的克隆与逆境胁迫响应分析

该研究基于茶树转录组和基因组信息,以茶树‘龙井43’为实验材料,从其cDNA中克隆获得茶树CsGME1基因,并对其蛋白序列特征、基因表达模式及其在不同非生物胁迫下的表达水平进行实时荧光定量分析。结果显示:(1)茶树CsGME1开放阅读框长度为1131 bp,编码376个氨基酸;该序列与多个相关物种的GME氨基酸序列一致性为94.25%,均含有NAD结合域。(2)进化树分析表明,茶树CsGME1基因与番茄SlGME1亲缘关系较近,与水稻OsGME2亲缘关系最远。(3)CsGME1蛋白属于亲水性蛋白,理论相对分子量为42046.84 Da,理论等电点为5.73,具有4个无序化区域,无序化程度较低;CsGME1蛋白二级结构由39.25%α-螺旋,13.26%延伸主链,5.84%β-转角和41.38%随机卷曲组成;三级结构分析结果显示,CsGME1包含螺旋和随机卷曲,与二级结构吻合。(4)荧光定量分析结果显示,在高温(38℃)、低温(4℃)、干旱(20%PEG)和高盐(200 mmol·L-1 NaCl)4种非生物胁迫处理下,茶树CsGME1基因均有响应,且表达存在差异,推测CsGME1参与了茶树的逆境胁迫响应过程。     

四季竹对土壤水分胁迫的生理适应

以四季竹2年生竹苗为材料,采用每天补水控制土壤含水量的方法,设置土壤相对含水率为<30%(T1)、40%～50%(T2)、60%～70%(T3)、80%～90%(T4)和竹蔸部完全水淹(T5)5个土壤水分含量水平,研究四季竹叶片在水分胁迫下的生理活性变化,以探讨四季竹对土壤水分的适应能力。结果表明:(1)随处理时间的延长,T1处理叶片离子渗漏率、MDA含量、叶绿素a/b值、SOD和POD活性、脯氨酸和可溶性蛋白含量均迅速升高,叶绿素含量、类胡萝卜素含量和叶绿素/类胡萝卜素比值迅速下降。(2)T5处理14d后叶片各生理指标随处理时间的延长与T1处理表现出相同的变化规律(类胡萝卜素和脯氨酸除外),并且分别在T1处理14d和T5处理28d后四季竹叶片全部干枯脱落。(3)随处理时间的延长,T2、T3、T4处理的四季竹叶片各生理指标经过一段时间的适应后最终稳定在处理前水平,且处理间均无显著差异。研究发现,四季竹在土壤相对含水率小于30%的土壤中生长不良,甚至死亡,在相对含水率40%～90%的土壤中能正常生长;四季竹耐受水淹胁迫的时间阈值是28d。     

19个茶树杂交新品系主要性状比较及其遗传多样性分析

为探讨茶树（Camellia sinensis）种质资源的遗传背景,加快新品种选育进程,对19份区试茶树新品系的农艺性状进行观测,结合SSR标记进行遗传多样性分析。结果表明,新品系1001 （‘春绿2号’）、1017、46-6为特早生种,萌发期比对照‘福鼎大白’早10 d以上;除1001是小乔木外,其余品系均为灌木;新品系叶形多为长椭圆形,1017品系为近圆形,1011与1012品系为近椭圆形。利用48对SSR引物对19个茶树新品系进行扩增,共扩增出231个等位基因（Na）,每对引物平均扩增出4.8个;多态性信息含量（PIC）为0.14~0.85,平均0.55,PIC超过平均值（0.55）的有28对引物,占引物总数的58.33%。聚类分析表明,在遗传距离为0.32时,29份种质资源可分为4类,第一类有1009、‘黄玫瑰’、‘黄旦’和‘黄观音’等4个,第二类有1011、1008、1014等16个,第三类有‘福鼎大白’、‘福云6号’、1017、1019、1015等5个;第四类有1001与‘早春毫’。这为茶树新品种的选育提供了种质资源。     

Influence of Phosphorus Application on Water Relations, Biochemical Parameters and Gum Content in Cluster Bean Under Water Deficit

Relative water content (RWC), leaf water potential (_w) and osmotic potential (_s), contents of chlorophyll (Chl) a, Chl b, soluble sugars, and seed quality (gum content) were used to evaluate the role of phosphorus in alleviation of the deleterious effect of water deficit in clusterbean (Cyamopsis tetragonoloba L. Taub). Under water stress, _w, _s, and Chl and gum contents decreased and soluble sugar contents increased. Phosphorus application increased Chl and sugar contents in control plants and ameliorated negative effects of water stress.     

Detection of Intra-Clonal Genetic Variability in Vegetatively Propagated Tea Using RAPD Markers

The role of random amplified polymorphic DNA (RAPD) markers in detecting intra-clonal genetic variability in vegetatively propagated UPASI-9 clone of tea (Camellia sinensis) was studied. Twenty five decamer primers were used, of which three did not amplify, three gave single bands and the rest of nineteen primers generated upto twelve bands (an average of 6.3 bands per primer). Twenty one primers exhibiting amplified products gave monomorphic banding patterns. Only one primer (OPE-17) gave a unique extra band of similar size in four plants.     

Changes in Mulberry Leaf Metabolism in Response to Water Stress

A series of experiments were conducted to characterize the water stress-induced changes in the activities of RuBP carboxylase (RuBPCO) and sucrose phosphate synthase (SPS), photosystem 2 activity, and contents of chlorophylls, carotenoids, starch, sucrose, amino acids, free proline, proteins and nucleic acids in mulberry (Morus alba L. cv. K-2) leaves. Water stress progressively reduced the activities of RuBPCO and SPS in the leaf extracts, the chlorophyll content, and PS2 activity in isolated chloroplasts. Plants exposed to drought showed lower content of starch and sucrose but higher total sugar content than control plants. While the soluble protein content decreased under water stress, the amino acid content increased. Proline accumulation (2.5-fold) was noticed in stressed leaves. A reduction in the contents of DNA and RNA was observed. Reduced nitrogen content was associated with the reduction in nitrate reductase activity. SDS-PAGE protein profile showed few additional proteins (78 and 92 kDa) in the water stressed plants compared to control plants.     

Effects of Paclobutrazol on Response of Two Barley Cultivars to Salt Stress

The seeds of two barley (Hordeum vulgare L.) cultivars (a drought resistant cv. Tokak-137/57 and a drought sensitive cv. Erginel-90) were imbibed either in distilled water (control) or in a solution containing 40 mg dm⁻³ paclobutrazol (PBZ) and air dried. Seeds were germinated and grown in a glasshouse for 21 d and seedlings were subjected to salt stress by treating them with 100 and 200 mM NaCl for 12 d. The height of shoots was significantly decreased and root length was increased in PBZ-treated plants prior and after NaCl stress for 12 d leading to an increase in root to shoot ratio. Leaf chlorophyll and carotenoid contents in PBZ treated plants were increased in controls and especially in plants subjected to salt stress. PBZ induced increase in superoxide dismutase (SOD) activities was higher in cv. Tokak-157/37, than in cv. Erginel-90. However, an increase in SOD activity was not accompanied by an increase in peroxidase activity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Photosynthetic Response of Barley Plants to Soil Flooding

72 to 120 h of soil flooding of barley plants (Hordeum vulgare L. cv. Alfa) led to a noticeable decrease in the rates of CO₂ assimilation and transpiration, and in chlorophyll and dry mass contents. Stomatal conductance decreased following flooding without appreciable changes in the values of intercellular CO₂ concentrations. A drop in the activity of ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39) and of the photorespiratory enzymes phosphoglycollate phosphatase (EC 3.1.3.18) and glycollate oxidase (EC 1.1.3.1) was observed, while the activity of phosphoenolpyruvate carboxylase (EC 4.1.1.31) increased in all flooded plants. Flooding of barley plants caused an increase in proline content and in leaf acidity.     

Rehydration of Sugar Beet Plants after Water Stress: Effect of Cytokinins

The possibility to improve the recovery of sugar beet plants after water stress by application of synthetic cytokinins N⁶-benzyladenine (BA) or N⁶-(m-hydroxybenzyl)adenosine (HBA) was tested. Relative water content (RWC), net photosynthetic rate (P_N), transpiration rate (E), stomatal conductance (g_s), chlorophyll (Chl) a and Chl b contents, and photosystem 2 efficiency characterized by variable to maximal fluorescence ratio (F_v/F_m) were measured in control plants, in water-stressed plants, and after rehydration (4, 8, 24, and 48 h). Water stress markedly decreased parameters of gas exchange, but they started to recover soon after irrigation. Application of BA or HBA to the substrate or sprayed on leaves only slightly stimulated recovery of P_N, E, and g_s in rehydrated plants, especially during the first phases of recovery. Chl contents decreased only under severe water stress and F_v/F_m ratio was not significantly affected by water stress applied. Positive effects of BA or HBA application on Chl content and F_v/F_m ratio were mostly not observed.     

极端干旱区疏叶骆驼刺叶绿素荧光对人工水分干扰的响应特征

选取塔里木河下游天然植被恢复示范区的疏叶骆驼刺(Alhagi sparsifolia Shap.)为研究对象,测定每年引水灌溉2次(每次0.42m3/m2)、1次和不灌溉(CK)处理下疏叶骆驼刺的实际光化学量子产量(ΦPSⅡ)、电子传输速率(ETR)和光化学猝灭系数(qP)等叶绿素荧光参数及其叶水势变化,探讨疏叶骆驼刺对人工水分干扰的叶绿素荧光响应特征。结果表明:(1)随着灌溉量的减少,疏叶骆驼刺叶水势呈显著降低的趋势,并在CK下达到最低。(2)同期疏叶骆驼刺qP、ΦPSⅡ、ETR、最大光量子产量(Fv/Fm)、叶绿素含量和光饱和点均随着灌溉量的减少呈先增加后降低的趋势,非光化学淬灭系数(NPQ)和调节性能量耗散(YNPQ)则呈先降低后增加的趋势。(3)与每年1次灌溉量处理相比,不灌溉和每年2次的灌溉量处理下疏叶骆驼刺发生了光抑制,光能捕获效率与光化学反应能量下降,热耗散能力提高。研究认为,灌溉量过高(每年2次,0.84m3/m2)或不灌溉均会限制疏叶骆驼刺光化学效率和光和活性,适时适量的(春季灌水1次,0.42m3/m2)水分补给更有利于疏叶骆驼刺适应干旱胁迫并维持正常光合生长。     

Heat Stress and Spermidine: Effect on Chlorophyll Fluorescence in Tomato Plants

Two tomato (Lycopersicon esculentum L.) cultivars: Robin (tolerant) and Roma (sensitive to heat stress) were studied. Chlorophyll fluorescence induction parameters (F_v/F_p, A_max, and Rfd) at 25 °C showed that the PS2 activity was similar for both cultivars. The parameters, measured at 38 °C, decreased in both cultivars, but more in cv. Roma. Exogenous application of 4 mM spermidine improved the plant heat-resistance in both cultivars, and especially in cv. Roma. Analysis of chlorophyll fluorescence changes during linear increase in temperature showed that cv. Robin plants have higher ability to hardening and higher resistance to thermal damage of the pigment-protein complexes structure and the activity of PS2 than cv. Roma.