氮、磷对小新月菱形藻无机碳利用与碳酸酐酶活性的影响

在实验室条件下研究了氮磷浓度变化对小新月菱形藻无机碳利用与碳酸酐酶活性的影响,结果显示小新月菱形藻随培养液中氮、磷浓度的升高比生长速率明显提高。低氮浓度导致胞外碳酸酐酶活性丧失,但胞内碳酸酐酶活性依然存在。高氮浓度下胞内、外碳酸酐酶活性均明显升高。胞内碳酸酐酶活性在高磷浓度下明显升高,但胞外碳酸酐酶活性并没有受到磷浓度变化的影响。高氮、磷浓度培养下的小新月菱形藻的最大光合作用速率(Vmax)、对CO2亲和力(K0.5(CO2))和光系统II最大光化学效率(Fv/Fm)均明显提高。以上结果表明小新月菱形藻可以通过改变胞内、外碳酸酐酶活性调节无机碳利用以适应不同氮磷浓度的环境。     

碳酸酐酶在中肋骨条藻光合作用中的作用

探讨了在正常空气条件下生长的中肋骨条藻(Skeletonema costatum)的碳酸酐酶(CA)在其光合固碳中的作用.在中肋骨条藻的胞内和胞外均有CA活性,但胞外CA活性很低.CA抑制剂AZ(乙酰唑磺胺)对中肋骨条藻的光合放氧速率没有明显影响,而CA抑制剂EZ(乙氧苯唑胺)对其光合放氧速率有强烈的抑制作用.EZ的抑制作用使细胞最大光合速率、饱和光强和无机碳亲和力下降,无机碳的补偿点和光呼吸提高,使强光下光抑制作用增强.这些结果表明:中肋骨条藻的胞外CA在其光合作用中所起的作用较小,而其胞内CA通过催化胞内碳库中的HCO-3快速转化成CO2,提高胞内CO2的有效供给,从而提高细胞光合固碳能力和对逆境(高O2、强光和低CO2)的适应能力.     

温度对4种大型海藻氮磷吸收效率及光合生理特性的影响

研究以裂片石莼(Ulva fasciata)、肠浒苔(Ulva intestinalis)、龙须菜(Gracilaria lemaneaformis)、坛紫菜(Pyropia haitanensis)为实验材料, 分析了不同温度(15、20、25、30℃)下4种大型海藻对海水中N、P元素的吸收效率和光合特性的特点。结果显示: (1)4种大型海藻对水体N、P均有明显的吸收效果, 吸收能力高低依次为肠浒苔>裂片石莼>坛紫菜>龙须菜; (2)温度过高或过低都会限制藻类对N、P的吸收和正常生长, 同时降低4种藻的相对电子传递速率及光化学效率; (3)裂片石莼与肠浒苔的N、P吸收能力强, 且光合系统对温度耐受性高, 是实施养殖污水生物净化的良好材料; (4)4种海藻对水体中N、P营养盐的吸收在48h内基本完成, 实地应用中可考虑24—48h周期换水或采用流通循环式的培养模式, 以达到既促进藻类的生长又提高营养盐吸收效率的目的, 以避免藻体因营养缺乏引起负生长而造成二次污染。     

高浓度CO2与磷浓度对葛仙米生长和光合作用的耦合效应

在不同CO₂(400和2000 ppm)和磷浓度下(0.088—0.350 mmol/L)培养葛仙米(拟球状念珠藻, Nostoc sphaeroides Kutzing), 研究CO₂和磷对葛仙米相对生长速率、色素含量、光系统Ⅱ光化学活性和光合速率等的影响。结果显示CO₂或磷浓度对葛仙米的相对生长速率、球体粒径和数量、光饱和光合速率、呼吸速率和光合效率均有显著影响, 且两者对球体粒径和数量、叶绿素a含量、呼吸速率和光合效率存在明显交互作用。高CO₂浓度培养明显提高磷对球体粒径和数量和光合效率的效应, 同时降低高磷浓度对叶绿素a合成的抑制作用, 但两者对相对生长速率、藻胆蛋白含量、光饱和光合速率、F_v/F_m和Yield的交互作用均不显著。以上研究结果表明高CO₂浓度或磷浓度增加促进葛仙米生长主要是通过提高光合速率和光合效率来实现; 两者交互作用表明高CO₂浓度可能通过提升磷的利用效率, 降低高磷浓度对叶绿素a合成的抑制, 提高光合效率, 使球体明显增大。     

不同氮素形态对向日葵生长和光合功能的影响

利用砂培试验研究了不同氮素形态对向日葵生长和光合功能的影响。结果表明：NO^3-N(NN)处理的株高、叶面积、干物质重显著高于NH4^ -N(AA)处理,施用NO3^--N的植株有较高的净光合速率(Pn)和较低的气孔导度(C8)、细胞间隙CO2浓度(Ci)。不同处理之间Fv／Fm没有显著差异,NN处理的植株PSⅡ线性电子传递量子效率ФPSⅡ、光化学荧光猝灭系数qP和表观光合电子传递效率ETR都显著高于AA处理的植株;而非光化学荧光猝灭系数qN则明显低于AA处理的植株。碳同化受到抑制是NH4^ -N条件下净光合速率下降的重要原因。     

大气CO_2浓度升高对不同氮生长条件下的两种大型海藻光合作用的影响

以龙须菜和蛎菜两种大型海藻为试验材料,在室外自然条件下培养,设置常规CO2浓度(390μL·L-1)和高CO2浓度(800μL·L-1)空气两种通气条件、以及10和150μmol·L-1两种氮营养盐供应水平,以探讨大气CO2浓度升高对不同氮营养盐生长条件下海藻生长与光合特性的影响。结果表明:不管是高氮还是低氮的培养条件,大气CO2浓度升高都能促进这两种海藻的生长;在龙须菜中,这种生长促进作用在低氮培养条件下更高,而在蛎菜中这种生长促进作用在高氮培养条件下较高;短期海水中高CO2浓度能促进蛎菜和龙须菜的光合作用;长期高CO2浓度生长环境依然能维持龙须菜高的光合作用,但抑制蛎菜的光合作用。另外,不管培养液中CO2供应条件如何,氮加富均促进了龙须菜和蛎菜这两种海藻的光全和呼吸作用。     

夜间变暖提高荫香叶片的光合能力

研究了不同氮供应的条件下夜间变暖对荫香叶片光合能力的影响。当植株生长在相同的日间温度(25℃),而夜间温度从18℃增至20℃时,叶片的光合速率增高(p<0.05)。高氮供应的植株,夜间变暖下其叶片光合速率较低氮供应的高,氮供应增高能促进夜间变暖提高叶片光合速率的效应。在低氮供给和夜间变暖下,植株叶片的光下呼吸和暗呼吸的增高显著(p<0.05)。无论在高氮或低氮供应下,生长在夜间变暖下的植物,其叶片的R ub isco最大羧化速率(Vcm ax)和光合电子传递最大速率(Jm ax)增高(p<0.05),氮供应能增强夜间变暖对Vcm ax和Jm ax的正向效应。夜间变暖降低植株叶片的比叶重,而增加单位叶干重的氮含量(Nm),单位叶面积的氮含量(Na)没发生明显变化。随着全球气候变化,夜间趋暖将有利于树木叶片光合能力的提高,结合高氮供给将会明显地增高植物的碳固定。     

中金杨幼苗叶功能性状与碳氮分配对氮添加的响应

氮沉降对森林生态系统产生了重要影响,但树木个体对氮沉降的生理生态响应过程和机制有待进一步明确。为探究杨树幼苗功能叶经济性状、植株生长以及生物量和碳氮分配对氮添加的响应,本文以欧美杂交杨中金杨2号(Populus×euramericana‘Zhongjin2’)幼苗为材料,研究了连续2年氮添加梯度处理(0、3、6和9 g NH₄NO₃·a^-1·plant^-1)对其叶片光合速率、叶经济性状、生长以及器官间碳氮分配的影响。结果表明：氮添加第一年,随氮添加浓度增加,中金杨叶片变大变薄,叶肉组织厚度显著降低,单位叶面积的净光合速率和气孔导度则随氮添加浓度增加而先升后降,而蒸腾速率、瞬时水分利用效率和光合氮利用效率不变;单株生物量和碳氮元素积累量显著增加,茎器官的碳投资显著增加而根的碳投资显著降低;氮添加第二年,功能叶光合固碳速率随氮添加量增加更快达到饱和,且高剂量氮添加处理表现出氮毒害现象;仅低量氮添加处理的单株生物量积累显著增加,并且进一步增加了对茎器官的碳投资,而中高剂量氮添加的根系生长明显受到抑制。氮添...     

NaCl和Na2CO3胁迫对桑树幼苗生长和光合特性的影响

以1年生“青龙桑”幼苗为试验材料,研究了中性盐(NaCl)和碱性盐(Na2CO3)胁迫下桑树幼苗的生长和叶片光合特性.结果表明:盐胁迫明显降低了桑树幼苗的株高、叶片数、生物量和叶片的光合能力.随着Na+浓度的增加,桑树叶片的气孔导度、蒸腾速率、净光合速率、实际光化学效率、电子传递速率和光化学猝灭系数明显降低,过剩光能以非光化学猝灭形式耗散的比例增加,桑树叶片的光能转化效率和光合能力下降.在Na+浓度＜150 mmol·L-1时,桑树幼苗的光合能力和生长受到的抑制较小,通过增加根冠比进一步适应盐胁迫,但这种保护机制随着盐浓度的增加逐渐降低.在Na2CO3胁迫下,＞50 mmol·L-1 Na+浓度对桑树的生长和光合能力表现出较强的抑制作用,并随Na+浓度的增加,抑制程度加大.在NaCl＜ 150mmol·L-1时,桑树的光合能力主要依赖植株形态和光合代谢双重途径适应中性盐逆境,而在NaC1浓度＞150 mmol·L-1和碱性盐胁迫下,其主要依赖光合代谢来适应逆境.     

不同光质LED弱光对樱桃番茄植株形态和光合性能的影响

基于新型LED光源研究了不同光质弱光对樱桃番茄植株形态和光合性能的影响.结果显示:(1)红蓝光(RB)的基础上添加不同的光色处理,对植株的形态没有显著影响,但对植株生物量有显著影响,能调节生物量的分配.除红蓝黄绿紫复合光处理(Z)外,其他复合光处理的单株总生物量都大于RB处理,添加绿光、黄光、紫光和黄紫光有利于植株地上部的生长,而添加绿光和紫光却抑制植株地下部的生长.(2)除红蓝黄紫复合光(RBYP)和红蓝紫复合光(RBP)处理外,所有处理的光合色素含量都比RB处理高,并以Z处理光合色素含量最高.(3)叶片的光补偿点和表观量子效率以及净光合速率受光质的调控.RBYP处理的最大净光合速率和表观量子效率显著大于其他处理,光补偿点在红蓝绿复合光(RBG)和红蓝黄复合光(RBY)下较大,而在白光(CK)和Z处理下较小.(4)各处理光系统Ⅱ的光能分配存在差异,RB处理光化学淬灭系数较其他处理小,而Z和RBP的非光化学淬灭系数较小,各处理间最大光化学效率及电子传递速率无显著差异.研究发现,复合光质的光色间对植株生长发育的影响是相互协同、相互制约的关系;红蓝黄紫复合光处理植株光合潜能较大,能够在一定程度上缓解红蓝弱光胁迫,促进植株幼苗生长;在红蓝光基础上添加其他光色有利于植株光合色素的积累并促进光合,同时可提高植株光化学效率.     

龙须菜对海水氮磷富营养化的响应

龙须菜(Gracilaria lemaneiformis)是红藻门江蓠属大型海藻,已从山东青岛引种到广东省南澳岛等地栽培多年。深入了解其光合作用与环境条件的关系,对龙须菜的合理栽培及其在环境生态中的生物学作用和扩大其开发利用价值,具有重要的理论和现实意义。该文利用人为配置的不同程度N、P污染海水处理龙须菜,研究其生理生态特性对海水氮磷富营养化的响应。结果表明: 处理6 d后,龙须菜叶绿素a及3种藻胆蛋白含量和总抗氧化能力在轻度P(P 0.2 mg·L^-1)及重度N、P复合污染(P 10 mg·L^-1,N 55 mg·L^-1)情况下降低。叶绿素荧光参数的变化也表明上述处理对叶绿体PSⅡ造成不利影响,而在轻度N(N 0.9 mg·L^-1)和轻度N、P复合污染(P 0.2 mg·L^-1,N 0.9 mg·L^-1)海水中上述参数则变化不大,表现出龙须菜对轻度N及轻度N、P复合污染的耐受性。该实验条件下,轻度污染处理后,藻体中不因环境N、P浓度升高而富集N、P。表明龙须菜可以作为轻度富营养化海水水体的净化藻类。     

龙须菜在不同盐度胁迫下的琼胶积累及相关生理生化变化的研究

为了探究不同盐度对龙须菜生长、琼胶合成及相关基因表达的影响, 研究了15、25和35三种盐度条件下龙须菜的生长速率、琼胶含量、琼胶合成酶α -半乳糖苷酶(GLA)、半乳糖苷转移酶(GAT)、α -1,3-糖脂磺基转移酶(GST)、半乳糖-2,6-硫酸化酶(GAS)的基因表达。结果表明, 盐度25时龙须菜生长速率最高, 为7.17%/d, 高于低盐(15)时的6.27%/d和高盐(35)时的3.57%/d, 低盐和高盐都表现出明显的暗呼吸速率上升和光合速率下降。龙须菜培养15d后, 在低盐条件下琼胶含量为9.27%, 盐度25和高盐分别为6.91%和8.09%。培养第3天时在低盐和高盐下龙须菜中gla基因表达量和酶活都显著高于盐度25的表达量; 15d后在盐度25条件下gla基因表达量仍然最低, 但GLA酶活无显著差异。gat基因在低盐条件下先降低后升高, 在高盐条件下表达量始终最高, 为盐度25的3.03倍。在低盐条件下gst和gas基因都在短期内出现显著下降, 但15d后恢复到与正常盐度无显著差异。龙须菜半乳糖含量在高盐条件下相对盐度25显著升高, 达到其3.27倍, 而在低盐条件下各种单糖含量相对较低, 半乳糖含量极低。研究结果说明过高和过低盐度都会对龙须菜造成一定程度的胁迫, 并促进琼胶的合成, 但其促进琼胶积累的机制存在差异, α -半乳糖苷酶和半乳糖苷转移酶在其中扮演着非常重要的角色。     

库布齐沙漠中甘草对不同水分和养分供应的光合生理响应

为了解全球变化背景下在沙漠分布的豆科优势物种甘草(Glycyrrhiza uralensis)对多因素环境变化的适应性, 该研究以第2年生长的甘草植株为对象, 盆栽试验为手段, 采用完全随机区组实验设计, 人工模拟分别相当于库布齐沙漠当地自然年降雨量的3/8、1/2、1和2倍(W1~W4)的4个水分供应处理, 以及4个养分添加处理(对照CK; N, 83 mg N·kg^-1土; P, 92 mg P·kg^-1土; NP, 83 mg N·kg^-1土+92 mg P·kg^-1土), 研究了库布齐沙漠中甘草的光合生理特性对于水分和养分供应变化的响应。结果表明: 气体交换特征随测量时间表现出规律性变化。在实验处理条件下, 每个植物功能性状参数随时间的变化趋势基本一致。当光合有效辐射(Photosynthetically available radiation, PAR)在11:00~13:00时段达到最高值时, 大气温度也接近测量当天的最高值, 净光合速率(Net photosynthetic rate, P_n)出现了明显的“午休”特征。第2年生长的甘草对于干旱胁迫表现出快速生理响应与气孔调节, 尤其在极度干旱(W1)条件下, 光合作用过程的控制在气孔限制与非气孔限制之间进行了多次转换。水分胁迫使P_n、气孔导度(Stomatal conductance, G_s)和蒸腾速率(Transpiration rate, T_r)等气体交换特征值下调, 同时降低了最大净光合速率(Maximum net photosynthetic rate, P_max)和表观量子效率(Apparent quantum yield, AQE)等光响应曲线特征参数。光合水分利用效率(Photosynthetic water use efficiency, PWUE)随着水分供应量减少而降低, 并且养分添加也使其在水分供应良好(W4)的条件下降低, 对于外界环境中水分利用的改变具有适应策略。另外, 养分添加对于光合作用过程具有促进作用, 尤其在水分供应良好的条件下, N素添加使P_n增加明显。在W1条件下, P素供应增加了P_max、光饱和点(Light saturation point, LSP)并减小了光补偿点(Light compensation point, LCP), 表明甘草物种对于P素的敏感性。研究结果表明, 虽然养分添加能够调节水分胁迫条件下甘草对于光辐射的利用效率与适应性, 但水分仍然是限制甘草光合生理的首要因素。     

NUTRITIONAL STUDIES OF TWO RED ALGAE. I. GROWT RATE AS A FUNCTION OF NITROGEN SOURCE AND CONCENTRATION1

Gracilaria foliifera (Forsskal) Borgesen and Neoagardhiella bailiyi (Harvey ex Kiitzing) Wynne & Taylor were grown in continuous-flow culture under controlled environmental conditions in 15 liter experimental chambers. Growth rate was related to the source and concentration of nitrogen enrichment supplied to the plants, Growth rate appeared to follow saturation-type nutrient uptake kinetics for plants receiving ammonium, nitrate, urea of sewage effluent enrichments. Ammonium enrichment produced higher growth rates than nitrate of sewage enrichment. The lowest growth rates occurred in the chambers receiving unenriched seawater or urea. The low estimated constants (K) for growth were in the range of 0.2–0.4 (M N for all N enrichments examined. The low estimated values of K compare closely with those found for microalgae and indicate that both species possess the ability to utilize very low concentrations of N.     

Effect of inorganic carbon supply on the photosynthetic physiology of Gracilaria tenuistipitata

Gracilaria tenuistipitata Zhang et Xia was cultured for 15 d at low, normal and high inorganic carbon concentrations under constant light, temperature and nutrient conditons. Carbonic anhydrase (CA; EC 4.2.1.1.) activity, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco; EC 4.1.1.39) content, pigment content and C/N ratio were measured, and also the photosynthesis and growth rates. Both Rubisco content and CA activity increased under conditions of low inorganic carbon (C_i) but decreased at high C_i with respect to the control. The amount of pigments declined considerably at high C_i and was slightly higher at low C_i. The maximum rate of photosynthesis and the photosynthetic efficiency increased in low C_i and the opposite was found at high C_i concentration. The effects of C_i concentration on maximum rate of photosynthesis and photosynthetic efficiency are discussed in relation to the variation in pigment and Rubisco contents and CA activity. The data indicate that C_i may be an important factor controlling the photosynthetic physiology of G. tenuistipitata with regard, not only to the enzymes of C_i metabolism, but also to the pigment content.Abbreviations APS_max maximum apparent photosynthetic rate - CA carbonic anhydrase - Chl chlorophyll - C_i inorganic carbon - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase This work has been supported by grants No. PB91-0962 and No. MAR90-0365 from Spanish Direction for Science and Technology (DIGICYT). M.J. G-S holds a fellowship from the DIGICYT.     

两种抗生素对龙须菜的光合生理效应

探讨了不同浓度的两种抗生素(氯霉素和青霉素G钠)对龙须菜(Gracilaria lemaneiformis)生长、光合作用、呼吸作用、色素含量以及可溶性蛋白含量等生理特性的影响。结果表明:龙须菜的生长受到两种抗生素的影响,但是氯霉素的影响要比青霉素G钠的影响大的多。在氯霉素处理的过程中,光合作用、有效光化学效率(Yield)、藻红藻蓝蛋白以及可溶性蛋白含量都随着氯霉素浓度的升高而显著下降,但是呼吸作用速率由于氯霉素的处理而升高;此外光合色素含量不受氯霉素的影响。在青霉素G钠的处理中,光合作用、有效光化学效率随着青霉素G钠的升高而下降,龙须菜叶绿素a与类胡萝卜素含量随着青霉素G钠浓度的升高而具有升高的趋势,但藻红蛋白、藻蓝蛋白以及可溶性蛋白在各处理组之间均没有表现出一定趋势。这些结果说明,氯霉素对生长的影响主要是光合作用速率的下降,以及有关蛋白合成下降引起,而青霉素G钠对生长的影响可能原因是呼吸作用速率的增加引起。由于龙须菜对氯霉素的敏感性比对青霉素G钠的敏感性更强,氯霉素在基因工程的育种中可能更适合作为选择压力。     

Photosynthetic response of P-deficient Gracilaria tenuistipitata under two different phosphate treatments

Phosphorus-deficient Gracilaria tenuistipitata Zhang et Xia was cultured for 15 days at two different inorganic phosphate (P_i) concentrations: 3 μM (low P_i treatmenl) or 30 μM phosphate (high P_i treatment). The amount of ribulose-l,5-bisphosphate carboxy-lase/oxygenase (Rubisco), phycobiliproteins, Chl a and total soluble proteins were higher in the high P_i than in the low P_i treatment. The total N content of the low P_i plants was lower than in plants grown at high P_i concentrations whereas the amount of total C was highest in low P_i plants. The increase of Rubisco content in the high P_i treatment (3-fold) was parallel to the enhancement of the maximum photosynthetic rate which increased 5-fold. This correspondence was also found in the low P_i treatment in which Rubisco content and maximum photosynthesis did not change significantly from the initial values. The photosynthetic efficiency was also higher at high than at low P_i. The high P_i plants also showed higher dark respiration and growth rates. The data presented here suggest that marine macroalgae submitted to P_i deficiency exhibit a decrease in growth caused not only by P_i implication on energy transfer in photosynthesis and respiration, but also by the diminution of the amount of photosynthetic pigments and Rubisco.     

Development of an eco-friendly agar extraction technique from the red seaweed Gracilaria lemaneiformis

The red seaweed, Gracilaria lemaneiformis growing as an aquaculture bioremediator along the coasts of Liaodong Peninsula, China, was investigated for the agar production. An eco-friendly method called agar photobleaching extraction process was developed for the benefit of workers' health and safety of the environment. The native agar (NA), alkali-modified agar (AA), chemical-bleached agar (CA) and photobleached agar (PA), which were extracted using different processes, were evaluated for their physical and chemical properties. The PA showed most desirable performances in terms of gel strength, gelling temperature, sulfate content and 3,6-anhydro-l-galactose content. Among the different processed agars, PA gel strength was 1913 g/cm2, the highest among the different processed agars, which increased 8.6% on the basis of the AA. Further we applied this new technique to extract agars from Gracilaria asiatica, and similar results were obtained with that of G. lemaneiformis. This indicates that the agar photobleaching extraction process is a feasible method for Gracilaria species and has a potential application. During the whole agar photobleaching extraction process the pigment content of G. lemaneiformis declined gradually and the TOC concentration in photobleaching solution increased along with the increase in the irradiation time. The mechanism of agar photobleaching could be elucidated by the photolysis theory.     

SEASONAL VARIATION OF P CONTENT AND MAJOR N POOLS IN PALMARIA PALMATA (RHODOPHYTA)1

The annual variation of major nitrogen pools, phosphorus, carbon, ash, and thallus water content in relation to seasonal environmental changes was studied in two northern Spanish populations of the edible seaweed Palmaria palmata (Linnaeus) Kuntze. Observed patterns were investigated using Spearman rank order correlation coefficients. There were significant relationships between thallus nutrient content and nitrate and orthophosphate seawater concentration, irradiance, temperature, and wave force. The highest levels of total N and P and nitrogenous compounds were observed during autumn and winter because the thallus stored N‐ and P‐rich compounds in response to high nutrient seawater concentration when growth was limited by low light and temperature. Phycoerythrin and other proteins were the main N reserves. Thallus P content was higher in algae from the eutrophic site. During spring, reduced N and P thallus content and increased ash, water, and C content were observed in the growing fronds. N and P seawater concentrations were undetectable during summer when nutrient reserves were low and growth was reduced and eventually suppressed, suggesting nutrient limiting conditions. Palmaria palmata clearly could take advantage of elevated N and P concentrations to create storage reserves in winter to support early summer growth. This storage response reduced the dependence of algal nutrition on the external nutrient supply and supports the use of pulse fertilization to diminish summer nutrient limitation of cultured algae.