水分和光照对厚皮甜瓜苗期植株生理生态特性的影响

以厚皮甜瓜‘西博洛托’为试材,研究了温室内育苗基质含水量和光照强度对厚皮甜瓜苗期植株生长发育和生理生态特性的影响.结果表明:不同基质含水量和光照强度对厚皮甜瓜苗期植株生长发育影响显著,随基质含水量的降低,苗期植株叶绿素a、叶绿素b和总叶绿素含量升高,叶片相对含水量和比叶面积下降,基质含水量为60%～80%时,幼苗净光合速率最高;随着光照强度的减弱,幼苗的叶绿素a、叶绿素b、总叶绿素含量以及叶片相对含水量、比叶面积和胞间CO2浓度升高,叶绿素a/b和净光合速率下降.在不同处理中,以80%基质含水量 100%温室光照处理的幼苗生长最健壮,壮苗指数、净光合速率等指标最高.     

氮沉降对乌药幼苗生理生态特性的影响

2010年6月-2011年7月,采用盆栽模拟氮沉降试验,比较了不同氮浓度处理(CK0g·m-2·a-1、低氮2 g·m-2·a-1、中氮8 g·m-2·a-1、高氮32 g·m-2·a-1)下乌药幼苗光合作用、相对叶绿素含量、叶绿素荧光参数、抗氧化酶活性及膜脂过氧化的差异,探讨氮沉降对乌药幼苗生理生态特性的影响.结果表明:经过1年的低氮、中氮和高氮处理,乌药幼苗叶片的日均净光合速率(Pn)和最大净光合速率(Pnmax)分别比对照增加了47.0％、117.8％、41.2％和82.6％、191.3％、152.2％;3种氮处理的乌药幼苗叶片日均Pn、Pnmax均以中氮处理最高.不同氮浓度处理后乌药幼苗叶片的日均胞间CO2浓度、日均气孔导度、光饱和点和表观量子效率均高于对照,暗呼吸速率以高氮处理最高.乌药幼苗叶片的相对叶绿素含量以中氮处理最高,其次是高氮处理,低氮处理与对照无显著差异.不同氮处理使乌药幼苗叶片的叶绿素荧光参数发生改变,PSⅡ原初光能转化效率、PSⅡ潜在活性均以高氮处理最低.3种氮处理的乌药幼苗叶片超氧化物歧化酶活性均高于对照,而过氧化物酶活性、丙二醛含量、膜透性均以高氮处理最高.氮沉降提高了乌药幼苗的光合能力,以中氮处理的效果最为明显,对其他生理指标也产生了不同程度的影响.     

翦股颖和高羊茅对铜、铅吸收及耐受性

测定了高羊茅和翦股颖两种草坪植物在Cu、Pb污染下发芽率、叶绿素、净光合速率和SOD的变化,以及两种草对Cu、Pb的吸收.结果表明, 重金属污染对高羊茅种子的萌发产生显著影响.高浓度Pb污染以及Pb、Cu复合污染对高羊茅的叶绿素影响很大,Cu单独污染对高羊茅叶绿素的抑制作用较小.翦股颖的叶绿素变化不显著.在3个Pb处理及350 mg·kg^-1 Cu处理下,翦股颖的SOD活性均高于对照,而只有在700 mg·kg^-1Pb 和350 mg·kg^-1 Cu+1 100 mg·kg^-1 Pb处理下高羊茅的SOD活性才升高.高羊茅的净光合速率受Cu污染影响较小,而受Pb污染影响较大.在Cu、Pb单独污染条件下,翦股颖净光合速率均呈下降趋势.从生理角度来看,翦股颖对Cu、Pb污染的耐受性强于高羊茅,而高羊茅对Cu污染的耐受性强于Pb.高羊茅Cu吸收量大,但Cu吸收量不随污染浓度升高而升高.翦股颖对土壤Pb的吸收能力较强, 且Pb吸收量随污染浓度的增加而增加.翦股颖和高羊茅可分别用于Pb和Cu污染土壤的治理.     

不同水分条件对人参榕生长和生理的影响

以3年生人参榕(Ficus microcarpa)为试材,采用盆栽调控水分的方法,研究5种不同的水分处理(基质最大含水量的90%～100%,70%～80%,50%～60%,30% ～ 40%和10%～20%)对人参榕生长和生理的影响,为栽培生产提供理论依据.结果表明:随着浇水量的减少,人参榕的株高、冠幅、块根增量均显著下降(P＜0.05);人参榕叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)活性显著增高(P＜0.05),细胞膜相对透性显著增强,脯氨酸和丙二醛(MDA)含量也显著增加;叶片净光合速率(Pn)和蒸腾速率(Tr)呈随浇水量的减少而显著降低;但叶片水分利用效率(WUE)呈显著增加趋势;各处理的叶片初始荧光(F0)和最大光量子效率(Fv/Fm)差异不显著.在各处理中,70%～80%的最大基质含水量的处理,其人参榕叶片的细胞膜相对透性最低,保护酶活性最弱,脯氨酸和丙二醛含量最低,净光合速率高,从而导致了人参榕具有生长最快、株高、冠幅和最大块根直径增量最大的特点.可见,70%～80%的最大基质含水量为是人参榕种植效果最好的水分管理模式.     

不同供水吸力对温室黄瓜光合特性及根系活力的影响

采用一种负水头供水控水盆栽装置,通过设定不同供水吸力（1、3、5、7、9、11、1 3 kPa）来控制不同土壤含水量,研究土壤水分对黄瓜光合、荧光参数的变化及根系生长的 影响.结果表明：供水吸力与土壤含水量呈反比对应关系,各处理控制的土壤含水量范围为 14.3%～42.2%;随供水吸力的增强,不同生育时期黄瓜叶片净光合速率都呈抛物线变化 趋势,初花期7～11 kPa处理和采收期3～5 kPa处理叶片的净光合速率较强,采收期9～13 k Pa的高供水吸力处理叶片净光合速率较低是由气孔限制因素导致的,而1～5 kPa低供水处理 下叶片PSⅡ光量子转化成化学能的效率较高,实际光化学效率较高,光抑制发生的可能性较 低;不同生育时期叶片叶绿素含量和蒸腾速率与净光合速率呈明显的正相关关系;随供水吸 力的增强,黄瓜根系生长及活力呈抛物线变化趋势,5 kPa处理的根系活力最高,7 kPa处理 的根系干物质量最大.说明3～7 kPa的供水吸力处理更有利于温室黄瓜根系生长与叶片净 光合速率的提高.     

高羊茅叶片表皮蜡质含量与其抗旱性的关系

以14个高羊茅品种为试验材料,在田间试验中对干旱高温胁迫下的叶片表皮蜡质含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度等生理指标测定分析。结果表明,干热胁迫下高羊茅品种间的叶片表皮蜡质含量和水分利用效率均存在极显著差异(P<0.01);叶片蜡质含量与综合抗旱性和水分利用效率的等级相关系数分别为0.78(P<0.01)和0.68(P<0.01);蜡质含量越高的品种,其叶片气孔导度和胞间CO2浓度越低,水分利用效率越高,但所有品种的水分利用效率绝对值都较低。研究发现,在干热胁迫时,高羊茅叶片表皮蜡质可通过对气孔导度的调节来减少气孔蒸腾,提高水分利用效率,最终提高其抗旱性;表皮蜡质含量可以作为高羊茅品种抗旱性鉴定的一个新指标。     

干旱和复水对大豆(Glycine max)叶片光合及叶绿素荧光的影响

选用河南省大面积种植的大豆品种豫豆29作为实验材料,通过研究逐步干旱和旱后复水条件下大豆叶片光合、叶绿素荧光等指标随土壤水分的动态变化规律,以期为大豆的水分高效利用提供理论依据。研究发现,在土壤相对含水量高于46.5%时,虽然随着土壤相对含水量的下降,豫豆29仍可以保持它的叶片水分状态;豫豆29的叶片净光合速率在土壤水分中等条件下最大,在土壤相对含水量为64.3%时,它比对照组高出11.2%(P<0.01);在实验的第3d,处理组的土壤相对含水量降为46.5%,叶片水势与对照组相比降低了7.2%(P>0.05),净光合速率为对照组的89.6%(P<0.05),但气孔导度却迅速下降为对照组的44.7%(P<0.01),这说明与叶片的光合和水分状况相比,豫豆29的气孔对土壤水分的匮缺更加敏感。复水后,豫豆29叶片的水势、净光合速率、气孔导度和叶绿素荧光等值都可以得到迅速的恢复,并在实验的最后接近对照组的水平,这表明豫豆29的叶片光合在水分胁迫解除后有迅速恢复的能力。     

不同灌水量下限对高羊茅绿期及抗寒性生理指标的影响

采用盆栽试验的方法,研究了秋末冬初不同灌水量下限\[分别占田间持水量(FC)的80%、70%、60%、50%\]对高羊茅绿期及抗寒性生理指标的影响.结果表明：在冬季低温条件下,80%和70%FC灌水处理使高羊茅叶片相对含水量、保护酶(SOD、POD和CAT)活性、叶绿素、可溶性糖和游离脯氨酸含量维持在较高水平,丙二醛含量和电解质外渗率降低,高羊茅的抗寒性增强.80%FC灌水处理分别较70%、60%和50%FC处理的草坪草绿期延长4、22和28 d,到达枯黄休眠的时间最晚,完成返青的时间最早.综合考虑节水和提高水分利用效率等多种因素,70%FC灌水处理为高羊茅秋末冬初季节最佳的灌水下限.     

不同灌水量下限对高羊茅绿期及抗寒性生理指标的影响

采用盆栽试验的方法,研究了秋末冬初不同灌水量下限\[分别占田间持水量(FC)的80%、70%、60%、50%\]对高羊茅绿期及抗寒性生理指标的影响.结果表明：在冬季低温条件下,80%和70%FC灌水处理使高羊茅叶片相对含水量、保护酶(SOD、POD和CAT)活性、叶绿素、可溶性糖和游离脯氨酸含量维持在较高水平,丙二醛含量和电解质外渗率降低,高羊茅的抗寒性增强.80%FC灌水处理分别较70%、60%和50%FC处理的草坪草绿期延长4、22和28 d,到达枯黄休眠的时间最晚,完成返青的时间最早.综合考虑节水和提高水分利用效率等多种因素,70%FC灌水处理为高羊茅秋末冬初季节最佳的灌水下限.     

黄连木对干旱胁迫的生理响应

研究了自然干旱条件下黄连木（Pistacia chinensis Bunge）的生理变化。结果表明,随土壤含水量的减少,叶绿素b含量、光合速率、叶片相对含水量与叶水势均下降;叶绿素a和可溶性糖含量、叶绿素a和b的比值及总叶绿素含量呈现上升的趋势;超氧化物歧化酶活性先升后降;丙二醛含量干旱胁迫前期升高,后期变化不明显;净光合速率、气孔导度和蒸腾速率随土壤含水量的减少逐步降低。气孔和可溶性糖含量都是影响黄连木光合速率的关键因子,干旱胁迫前12d光合速率主要受气孔限制,之后为非气孔限制。干旱胁迫前期渗透调节物质以可溶性糖为主,干旱胁迫较重时脯氨酸含量急剧升高,与可溶性糖同时起渗透调节作用。     

Effects of foliar application of nitrogen on the photosynthetic performance and growth of two fescue cultivars under heat stress

The effects of nitrogen fertilization on the growth, photosynthetic pigment contents, gas exchange, and chlorophyll (Chl) fluorescence parameters in two tall fescue cultivars (Festuca arundinacea cv. Barlexas and Crossfire II) were investigated under heat stress at 38/30 °C (day/night) for two weeks. Shoot growth rate of two tall fescue cultivars declined significantly under heat stress, and N supply can improved the growth rates, especially for the Barlexas. Chl content, leaf net photosynthetic rate, stomatal conductance, water use efficiency, and the maximal efficiency of photosystem 2 photochemistry (F_v/F_m) also decreased less under heat stress by N supply, especially in Crossfire II. Moreover, cultivar variations in photosynthetic performance were associated with their different response to heat stress and nitrogen fertilization, which were evidenced by shoot growth rate and photosynthetic pigment contents.     

高温对仁用杏光合特性及PSⅡ光化学活性的影响

为探讨高温胁迫下仁用杏叶片的光合适应机制,以科尔沁沙地生长的4年生'超仁'仁用杏为试材,设置环境温度为25℃、30℃、40℃和50℃处理,利用气体交换技术和快速叶绿素荧光诱导动力学曲线分析技术(JIP-test),研究了仁用杏叶片光合特性和PSⅡ光化学活性.结果表明:在一定温度范围内,随着温度升高,仁用杏通过提高光合色素含量和比例来维持光能的吸收、传递和转换能力,从而保证光合机构正常运转;当高温超过叶片自身生理调节限度后,叶绿素发生分解、净光合速率(Pn)明显下降、胞间CO2浓度(Ci)上升,说明光合作用的下降是由叶肉因素造成的.温度40℃导致单位面积有活性反应中心数量(RC/CSo)显著下降;而50℃高温下荧光诱导曲线中K点(Wk)和J点(Vj)明显增加,高温对仁用杏叶片放氧复合体(OEC)、受体侧和PsⅡ反应中心造成了伤害.此外,50℃高温还导致初始荧光(Fo)显著升高,为对照的2.26倍,PSⅡ最大光化学效率(Fv/Fm)和光化学性能指数(PI/ABS)分别下降为对照的37.9%和10.3%.高温损害了PSⅡ供体侧和受体侧的功能,造成光合效率下降,这是高温胁迫对仁用杏叶片光合机构伤害的主要机制之一.     

Grasses of different C4 subtypes reveal leaf traits related to drought tolerance in their natural habitats: Changes in structure, water potential, and amino acid content

Three grasses (Poaceae) of different C(4) subtypes, Paspalum dilatatum (NADP-malic enzyme [ME]), Cynodon dactylon (NAD-ME) and Zoysia japonica (phosphoenolpyruvate carboxykinase), occur in natural habitats that differ in annual rainfall. Their leaf characteristics were studied to identify traits related to drought tolerance. Plants were grown in pots, and water deficit was gradually induced by withholding water. Leaves of Z. japonica had the greatest and P. dilatatum the lowest relative dry matter content. Transverse sections of leaves that developed during the water deficit showed little change compared to control leaves, consistent with low phenotypic plasticity. Anatomical features distinguished the three species, with xeromorphic characteristics most strongly represented in Z. japonica. The leaf relative water content (RWC) decreased with the soil water content similarly for the three grasses. However, at 80% RWC, the leaf water potential was -3.1 MPa for Z. japonica and only -1.3 MPa for P. dilatatum and C. dactylon. Soluble amino acids, especially proline, increased as RWC decreased in leaves of C. dactylon and Z. japonica. Phenylalanine, valine, leucine, and isoleucine increased more in Z. japonica than in the other two species. The results provide evidence that C. dactylon and, especially, Z. japonica have evolved leaf traits better suited to arid habitats.     

甘蔗抗旱性生理生化鉴定指标

利用因子分析和灰色关联度分析方法研究了甘蔗叶片相对含水量、膜脂过氧化代谢、活性氧代谢、光合参数及蔗茎产量性状等指标与抗旱性的关系.结果表明,干旱胁迫下甘蔗叶片的MDA含量和PMP明显提高,而RWC、SOD活性、Chl含量、F_v/F_m、F_v/F_o、△F_v/F_t、△F_v/F_o和蔗茎单茎重(SSW)8个抗旱性指标均显著降低.SSW与其它9个生理生化指标的相关性大小依次为PMP＞SOD活性＞MDA含量＞RWC＞F_v/F_o＞F_v/F_m＞Chl含量＞F_v/F_o＞F_v/F_t,其中,SSW与F_v/F_o和ΔF_v/F_t相关性不显著.通过因子分析将10个甘蔗抗旱性指标用4个公共因子表示,累加方差贡献率达到92.08%.因子l主要是反映光合作用特性指标对甘蔗品种抗旱性起支配作用,因子2主要是反映叶片相对含水量及活性氧代谢指标对甘蔗品种抗旱性起支配作用,因子3和因子4分别只有SSW和Chl含量有较大载荷.灰色关联度分析表明,各抗旱性生理生化指标与SSW关联密切程度依次为F_v/F_m＞PMP＞F_v/F_o＞RWC＞MDA含量＞SOD活性＞ΔF_v/F_t＞Chl含量＞F_v/F_o.     

绿斑病藻寄生对夏橙叶片光合作用特性的影响

以盆栽的2年生奥灵达夏橙为试材,研究了绿斑病藻寄生对夏橙叶片光合作用特性的影响.结果表明,轻度病叶对叶绿素总量（Chl a+b）、类胡萝卜素含量（Car）、净光合速率（P_n）、胞间CO₂浓度（C_i）、原初光能转换效率（F_v/F_m）、光合电子传递量子效率（ΦPS Ⅱ）和光化学猝灭系数（qP）无显著影响;中度病叶和重度病叶的Chla+b、Car、P_n、F_v/F_m、ΦPS Ⅱ和qP较对照分别下降了23.85%、26.49%、43.3%、4.5%、35.1%、22.5%和37.61%、44.04%、64.5%、8.6%、63.6%、40.1%,与对照差异显著,而C_i较对照显著上升.绿斑病藻的大量寄生减弱了夏橙叶片的光合作用,而净光合速率的下降主要是由非气孔因素限制引起.     

Photosynthetic pigments,morphology and leaf gas exchange during ex vitro acclimatization of micropropagated CAM Doritaenopsis plantlets under relative humidity and air temperature

The effect of relative humidity (RH) and temperature on CO₂ assimilation (An), stomatal conductance (Sc), transpiration rate (Tr), chlorophyll content, fresh and dry weight, leaf length, leaf area, leaf width, formation of new root and survival rate have been assayed in Doritaenopsis in growth chamber after 1 month of acclimatization. Reduced growth was observed at below and above 25 °C whereas it was increased with increasing humidity. Relative water content (RWC) was decreased at 50% and 70% humidity after second day of transfer and recovered completely with the progression of acclimatization. RWC also reduced at high temperature but recovered slowly and a gradual decrease of RWC was observed at 15 °C. A visual symptom of severe leaf tip burn was observed at 50–70% humidity and at 35 °C during acclimatization. At 15 °C and 50% humidity sudden decrease of photosynthetic efficiency (F_v/F_m) was observed, which could not recover in temperature treated plantlets during acclimatization period. Chlorophyll content increased with increasing humidity and at 15 and 35 °C chlorophyll content was decreased compared to 25 °C. Chlorophyll a/b ratio was unchanged while total chlorophyll/carotenoids ratio was increased from low to high temperature. Exposure of plantlets to high temperature led to a noticeable decrease in An, Sc and Tr, and at 15 °C they were more decreased whereas significant differences were not observed in the parameters tested under humidity after 25 days of acclimatization. During daytime at 15 °C, increase in An, Sc and Tr indicates the plantlets adaptability in the new environment. The peroxidase activity remained unaffected in all humidity stress whereas low temperature increased the peroxidase activity compared to high temperature. These finding suggests that photosynthetic properties was greatly affected by air temperature conditions with a reduction of An, Sc and Tr at 15 and 35 °C compared to humidity stress that played a greater role in limiting photosynthesis.     

Paraheliotropism in Robinia pseudoacacia L.: an efficient strategy to optimise photosynthetic performance under natural environmental conditions

We assessed the contribution of leaf movements to PSII photoprotection against high light and temperature in Robinia pseudoacacia. Gas exchange and chlorophyll a fluorescence measurements were performed during the day at 10:00, 12:00, 15:00 and 18:00 hours on leaves where paraheliotropic movements were restrained (restrained leaves, RL) and on control unrestrained leaves (UL). RL showed a strong decrease of net photosynthesis (A(n)), stomatal conductance (g(sH2O)), quantum yield of electron transport (PhiPSII), percentage of photosynthesis inhibited by O2 (IPO) and photochemical quenching (q(P)) in the course of the day, whereas, a significant increase in C(i)/C(a) and NPQ was observed. Contrary to RL, UL had higher photosynthetic performance that was maintained at elevated levels throughout the day. In the late afternoon, A(n), g(sH2O), PhiPSII and q(P) of RL showed a tendency to recovery, as compared to 15:00 hours, even if the values remained lower than those measured at 10:00 hours and in UL. In addition, contrary to UL, no recovery was found in F(v)/F(m) at the end of the study period in RL. Data presented suggest that in R. pseudoacacia, leaf movements, by reducing light interception, represent an efficient, fast and reversible strategy to overcome environmental stresses such as high light and temperature. Moreover, paraheliotropism was able to protect photosystems, avoiding photoinhibitory damage, leading to a carbon gain for the plant.     

珊瑚树阳生和阴生叶片光合特性和状态转换的比较

珊瑚树阳生和阴生叶片是在不同光照环境中长期生长的,它们的光合特性有一些明显的差异.与阳生叶片相比,阴生叶片单位干重的叶绿素含量较多,类囊体膜垛叠程度较高(即每个基粒的类囊体膜垛叠层数较多,基粒类囊体的直径较大),而叶绿素a/b比值、光合作用的饱和光强和最大净光合速率等较低.用弱红光诱导阳生和阴生叶片向状态2转换时,叶绿素荧光Fm/Fo和F685/F735先迅速下降再逐渐回升,这表明两种叶片都先后通过满溢和LHCⅡ转移调节激发能在PSⅡ和PSⅠ之间的分配,改善光能利用,但阳生叶片Fm/Fo和F685/F735下降的幅度较大.     

大田增温对夏玉米光合特性的影响

在大田条件下研究了增温对两个夏玉米品种农大108(ND108)和掖单13号(YD13)光合特性及产量的影响.结果表明:大喇叭口期到成熟期增温显著降低了夏玉米籽粒产量,ND108和YD13的籽粒产量分别较对照降低了46.6%和45.1%;叶面积指数平均值分别降低了15.4%和11.5%;穗位叶叶片光合速率平均值分别降低了22.85%和18.14%;两个玉米品种叶片的叶绿素a和叶绿素b含量显著降低,但对叶绿素a的影响更显著.增温后玉米叶片的磷酸烯醇式丙酮酸羧化酶(PEPCase)和核酮糖二磷酸羧化酶(RuBPCase)活性都显著降低,ND108、YD13叶片的PEPCase和RuBPCase活性分别较对照降低了51.1%、32.4%和29.5%、7.7%.