红松幼苗对CO2浓度升高的生理生态反应

研究了用开顶箱控制CO     

人工栽培沙葱的光合生理特征

沙葱是一种旱生鳞茎草本植物,具有很高的光合速率.研究结果表明,大田栽培沙葱5月~8月中旬的日平均净光合速率分别为19.86、15.45、11.72和10.33μm o l CO2.m-2.-s 1,呈不断降低趋势.沙葱光补偿点为58.9μm o l photons.m-2.-s 1,喜光但有一定的耐荫性.CO2补偿点为158.2μL.L-1,增加CO2能明显提高沙葱的光合速率.另外,刈割能明显提高沙葱的光合速率,但正常灌水周期外的补灌对提高沙葱光合速率无明显作用,其光合速率大小是多种因子作用的综合结果,与大气环境因子间的回归方程为Y=0.003 78QNTM 0.013 4CO2-0.663TA-0.274RH 0.466VPD 13.455(R2=0.99).     

12个不同基因型冬小麦的光合能力

 研究了12个不同基因型冬小麦(Triticum aestivum)品种(其中两个为北京本地品种)的光合能力。结果表明：小偃22、陕麦897和8907-11-5三个品种的净光合速率超过20μmolCO2·m-2·s-1,均比其它实验品种高,其PSⅡ总的光化学量子产额(Yield)、光化学荧光猝灭系数(qP)和水分利用效率(WUE)也较高;而其暗呼吸速率和非光化学荧光猝灭系数(qN)较低,表现出具有良好的光合生理功能,而且这些参数具有连锁相关的趋势。因此,北京地区要引种外地具有优良光合生理功能的冬小麦作为栽培品种或育种亲本时,在所实验的10个外地品种中,上述3个品种应为首选品种。     

常绿阔叶树种栲树幼苗对不同光环境的光合生理响应

常绿阔叶树种栲树是亚热带常绿闭叶林中的优势种之一.对比研究了林下、林窗和旷地3个光环境下栲树幼苗的光合特征参数、比叶质量、叶氮含量及叶解剖结构等,结果表明:林下栲树幼苗的光补偿点和暗呼吸速率低,比叶质量小,表观量子效率和光合氮素利用率高,利用弱光的能力强,在低光环境下保持了较高的光合能力;海绵组织发达且表皮细胞厚,是对凉爽环境的积极响应.在旷地,栲树的最大光合速率明显下降,暗呼吸速率显著升高,单位面积的叶氮含量较高但氮素利用率较低;叶厚度和栅栏组织厚度均增加,栅栏组织/海绵组织厚度比值也升高了,但栅栏组织不如海绵组织发达,不能适应高光环境.栲树幼苗在林窗有较高的光合能力,在林窗中能正常生长和更新.     

红松幼苗对CO_2浓度升高的生理生态反应

研究了用开顶箱控制CO2 浓度在 5 0 0和 70 0 μmol·mol-1左右时红松幼苗的生理生态反应 .结果表明 ,高浓度CO2 (5 0 0、70 0 μmol·mol-1CO2 )和对照 (对照开顶箱、裸地 )条件下 ,红松幼苗的净光合速率与气孔导度之间的变化不同 .红松幼苗在 5 0 0 μmol·mol-1CO2 条件下 ,RuBPcase活性最高 ,呈现光合上调反应 ,日平均净光合速率最大 ,叶绿素及可溶性糖含量最高 ;而生长在 70 0 μmol·mol-1CO2 的红松幼苗呈现光合下调反应 ,光合作用明显低于对照植株 ,其酶活性及物质含量均最低     

边缘效应带促进红松生长的光合生理生态学研究

以一个经过12a边缘效应带处理的14年生红松幼林生态系统为研究对象,通过对3种宽度(4m,6m,8m)边缘效应带及保留带内红松幼树的光合日进程、碳素日积累量及相关生理生态学因子(光照、气孔导度、小枝木质部水势、叶片温度、叶面饱和蒸气压亏缺)的研究,探讨了造成不同效应带和保留带内红松生长差异的光合生理生态学原因。结果：4m效应带光照不足引起的碳素日积累量过低导致红松生长较差,8m效应带气孔导度过低引起的光合午休现象导致了碳素日积累量低、红松生长较差。8m效应带引起气孔导度下降的因素主要是过强光照引起叶片温度较高、叶面饱和蒸气压亏缺较大以及小枝木质部水势过低。研究认为,太宽的8m带和太窄的4m带都在一定程度上引起了光合生理生态学的不适应,导致生长水平下降,6m宽度的边缘效应带是人工促进红松生长的最佳边缘效应带。     

遮光处理对山杏幼苗光合特性的影响

以3年生山杏苗木为材料,用CIRAS-2型光合仪测定70%和40%遮光处理下其叶片光合生理参数的光响应和日变化特征,以探讨山杏光合特性对光照条件的适应机制.结果表明:(1) 随着遮光处理的加重,山杏叶片净光合速率(Pn)、光补偿点、光饱和点、暗呼吸速率及生物量等均呈下降趋势,70%和40%遮光处理下山杏叶片最大Pn分别比全光照显著下降58%和38%,而其表观量子效率分别显著提高31%和22%.(2)遮光处理下,山杏叶片Pn日变化呈"单峰"曲线,70%和40%遮光处理山杏叶片Pn日均值分别比全光照显著下降68%和49%;随着环境光照的增强,山杏叶片Pn下降的原因逐渐由气孔限制转变为非气孔限制为主.(3) 随光照强度的增加,山杏叶片蒸腾速率表现为增大趋势,70%和40%遮光处理的均值分别比全光照下降55%和16%;弱光环境下山杏具有降低蒸腾作用来提高水分利用效率的生理特性,水分利用效率均值和最大值均表现为70%遮光>全光照>40%遮光.研究发现,山杏较喜光,但对弱光也有一定适应能力,光照生态幅较宽,在干旱缺水的黄土丘陵区适当遮荫可提高其对有限水分的利用效率.     

水淹对水竹光合生理特征的影响

为探究耐淹速生竹种水竹对不同程度水淹胁迫的光合生理响应,以一年生水竹(Phyllostachys heteroclada)为试验材料,以正常浇水为对照组,测定根部全淹及根部半淹处理下水竹光合气体交换参数、光合色素及叶片资源利用效率随水淹时长产生的差异。结果表明：水淹胁迫第3天,半淹处理的水竹叶片净光合速率、光饱和点和蒸腾速率较对照均出现显著上升,而全淹胁迫下则无显著差异,其后均随胁迫时间的延长而下降,下降幅度与胁迫程度呈正相关;水淹胁迫处理第6天,水竹叶片气孔导度均显著高于对照组,后呈下降趋势;水淹胁迫导致水竹胞间CO₂浓度呈现先下降后上升的趋势,至第9天与对照组的数据差异不显著,其恢复时长与胁迫程度呈正相关;暗呼吸速率及光补偿点则随胁迫时长的增加而上升;总光合色素呈现先下降后上升趋势,叶绿素与类胡萝卜素的比例仍保持在3∶1,而叶绿素a与叶绿素b的比例从3∶1下降至2∶1;叶片水分利用率呈现先下降后上升的趋势,而表观光能利用率与表观CO₂利用率均呈现下降趋势,其下降幅度随水淹时长的延长而逐渐减小。研究表明,半淹胁迫短期内对水竹的光合作用表现出...     

田间增加UV-B辐射对玉米光合生理的影响

自然条件下,分别增加0(CK组)、0.01(R1组)和0.015 J.m-2.s-1(R2组)3种强度的UV-B辐射处理玉米(Zea maysL.),对重庆地区C4植物玉米整个生长期内光合作用的影响进行研究。结果表明,增强UV-B辐射导致玉米幼苗叶片光合色素含量(包括叶绿素a、叶绿素b、总叶绿素和类胡萝卜素)、Hill反应活力、气孔导度、光合速率下降,且随UV-B辐射强度的增加,玉米幼苗光合作用所受抑制增强,而玉米成株所受影响不大。     

红松幼苗对CO2浓度升高的生理生态反应

研究了用开顶箱控制CO₂浓度在500和700μmol·mol^-1左右时红松幼苗的生理生态反应.结果表明,高浓度CO₂(500、700μmol·mol^-1CO₂)和对照(对照开顶箱、裸地)条件下,红松幼苗的净光合速率与气孔导度之间的变化不同.红松幼苗在500μmol·mol^-1CO₂条件下,RuBPcase活性最高,呈现光合上调反应,日平均净光合速率最大,叶绿素及可溶性糖含量最高;而生长在700μmol·mol^-1CO₂的红松幼苗呈现光合下调反应,光合作用明显低于对照植株,其酶活性及物质含量均最低.     

Photosynthetic performance and light response of two olive cultivars under different water and light regimes

The olive tree (Olea europaea L.) is commonly grown in the Mediterranean area, where it is adapted to resist periods characterized by severe drought and high irradiance levels. Photosynthetic efficiency (in terms of F_v/F_m and Φ_PSII), photochemical (q_P) and nonphotochemical quenching (NPQ) were determined in two-year-old olive plants (cultivars Coratina and Biancolilla) grown under two different light levels (exposed plants, EP, and shaded plants, SP) during a 21-day controlled water deficit. After reaching the maximum level of drought stress, plants were rewatered for 23 days. During the experimental period, measurements of gas exchange and chlorophyll (Chl) fluorescence were carried out to study the photosynthetic performance of olive plants. The synergical effect of drought stress and high irradiance levels caused a reduction of gas exchange and photosynthetic efficiency and these decreases were more marked in EP. EP showed a higher degree of photoinhibition, a higher NPQ and a lower q_P if compared to SP. Coratina was more sensitive to high light and drought stress but also showed a slower recovery during rewatering, whereas Biancolilla showed a less marked photosynthesis depression during drought and a considerable resilience during rewatering. The results confirm that photoinhibition due to high light intensity and water deficit can be an important factor that affects photosynthetic productivity in this species.     

Photosynthetic characteristics of ornamental passion flowers grown under different light intensities

Responses of leaf gas exchange, fluorescence emission, chlorophyll concentration, and morpho-anatomical features to changes in photosynthetic photon flux density (PPFD) were studied in three wild ornamental species of Passiflora L. to select sun and shade species for landscaping projects. Artificial shade was obtained with different shading nylon nets, under field conditions, which allowed the reduction of 25, 50, and 75% of global radiation, along with a control treatment under full sunlight. For Passiflora morifolia the highest mean values of light-saturated net photosynthetic rate (P _Nmax) and light compensation point (LCP) were observed at 50 and 25% shade, respectively, while the highest values of dark respiration rate (R _D) and apparent quantum yield (α) were observed at 75% shade. For Passiflora suberosa litoralis the highest value of P _max was observed at full sunlight. The highest mean values for P _max, R _D, and LCP for Passiflora palmeri var. sublanceolata were obtained at 25% shade. The highest values of net photosynthetic rate (P _N) for P. morifolia, P. palmeri var. sublanceolata, and P. suberosa litoralis were 21.09, 16.15, and 12.36 μmol(CO₂) m⁻² s⁻¹, observed at 50 and 75% shade and full sunlight, respectively. The values of the minimal chlorophyll fluorescence (F₀) were significantly different in P. suberosa litoralis and P. palmeri var. sublanceolata, increasing with the increase of the irradiance. In contrast, the values of maximum photochemical efficiency of PSII (F_v/F_m) were significantly different only in P. suberosa litoralis, being higher at 75%, progressively reducing with the increase of PPFD levels. The total concentration of chlorophyll (Chl) was higher in shaded plants than in the ones cultivated in full sunlight. On the other hand, the values of Chl a/b ratio were reduced in shaded plants. A significant effect of shade levels on leaf area (LA) and specific leaf area (SLA) was found for the three species, whose highest mean values were observed at 75% shade. The thickness of foliar tissues was significantly higher for the three species at full sunlight and 25% shade. These results suggested that P. morifolia and P. palmeri var. sublanceolata appeared to be adapted to moderate shade conditions. P. suberosa litoralis presented higher plasticity to greater variation of the irradiance levels, while the photoinhibition was one of the limiting factors for this species at full sunlight.     

不同基因型辣椒光合及生长特性对弱光的响应

通过遮光使光照强度降低65%～70%,以研究弱光条件对不同基因型辣椒光合特性、同化物分配、产量形成和幼苗生长的影响.结果表明：弱光下辣椒净光合速率（P_n）、暗呼吸速率（R_d）、夜间呼吸速率（R_n）、蒸腾速率（T_r）、水分利用效率（WUE）、光补偿点（LCP）、CO₂补偿点（CCP）和羧化效率（CE）下降,表观量子效率（AQY）上升.弱光下辣椒成株期光合作用的限制因素是非气孔因素.弱光处理使辣椒幼苗高/粗比和比叶面积增加,根/冠比、全株干样质量及壮苗指数显著下降.弱光显著抑制了辣椒生物产量与经济产量的形成,使植株同化物向茎叶的分配比例增加,向果实的分配比例减少.辣椒（果实味辣）在弱光下具有较低的光补偿点,以及较高的相对壮苗指数、相对单株产量和相对坐果率,耐弱光性普遍强于甜椒（果实味甜）.     

不同透光环境下红松光合色素含量的季节变动及应对策略

研究了辽东山区天然次生林内3种不同透光环境(强度透光、中度透光和弱度透光)下红松针叶光合色素(叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)和叶绿素总量(Chl T))应对光环境季节变动做出的适应性调整。结果表明,随季节的变动(从春季至秋季),林分透光孔隙度逐渐减小。春季,透光度越大,红松叶绿素含量越高,Chl a/b值升高,Car/Chl T值降低;夏季,不同透光条件对红松光合色素含量无影响;秋季,各类透光条件下红松光合色素含量总体表现为升高的趋势,强度透光与中度透光条件红松针叶Chl a/b显著大于弱度透光,3种透光条件下红松Car/Chl T均降低。在春季红松开始生长前进行适当抚育,能提高光合色素含量,增强光合作用能力,促进生长。     

Growth characteristics of root-shoot relations of three birch seedlings raised under different water regimes

Three birch species (Betula ermanii, B. maximowicziana, B. platyphylla var. japonica) widespread in northern Japan were raised under different water regimes (ca. 23, 35, and 60%) to study root-shoot increment and gas exchange traits in relation to their habitat preferences in natural conditions. Total biomass of all birches was larger for medium, wet and dry treatment. Maximum root length of B. platyphylla raised at dry or wet condition was higher than other species. Root growth rate of three birches peaked around mid July to early September while shoot growth rate was found maximum between late June and mid August. Root growth of three birches was suppressed under dry and wet treatment, especially for B. ermanii. Allocation percentage of biomass to roots of three birches ranged from 30 to 40% but it mainly allocated to elongate the root length under dry and wet condition. Fine roots of B. ermanii and B. maximowicziana under wet condition were distributed mainly on soil surface. In the dry treatment, B. platyphylla allocated photosynthates to elongate the root length and fine root production (<2 mm) and had highest plasticity of roots to different water conditions among the three birches. Specific leaf area (SLA) of three birches decreased with decreasing soil moisture content. Plasticity in SLA of B. platyphylla was found largest. Net photosynthetic rate (Pn) and water use efficiency (WUE) of B. platyphyllashowed highest among all the treatments. Leaf nitrogen content of B. platyphyllawas also relatively higher under different water conditions as compared to the other two birch species, suggesting B. platyphylla may enable to invade to various growing conditions with different water regimes.     

不同二氧化碳浓度条件下红松和长白赤松幼苗根际土壤微生物数量研究

以连续5年不同CO₂浓度(开顶箱700μmol·mol^-1、500μmol·mol^-1、对照箱和裸地)处理的长白赤松和红松幼苗为研究对象,在2003年7～9月分别对幼苗根际土壤细菌、真菌、放线菌数量进行比较研究.结果表明,高浓度CO₂处理对长白赤松幼苗根际土壤细菌数量起显著的(P≤0.001)促进作用,对根际真菌和放线菌数量的促进作用却不明显;对红松来说,除8月份700μmol·mol^-1CO₂处理和7月份500μmol·mol^-1CO₂处理之外,在各月份中受高浓度CO₂处理的根际土壤细菌数量均较对照箱和裸地显著增多(P≤0.001),而根际土壤真菌数量变化除9月份(P≤0.001)外均不明显,放线菌数量受高浓度CO₂的影响亦不明显.     

Differences in morphology, gas exchange and root hydraulic conductance before planting in Pinus canariensis seedlings growing under different fertilization and light regimes

As the main forestry species in the Canary Islands (Spain), Pinus canariensis is frequently used in afforestation programs. Several nursery techniques are commonly employed to modify its morphology and physiology with the aim of improving post-planting survival and growth. In this work, we studied how fertilization and light regime treatments applied during the nursery period modify biomass allocation patterns and produce effects in gas exchange and root hydraulic conductance. Seedlings were grown for a 6-month period in the nursery under two light regimes (full sunlight and 40% PAR reduction), and three fertilization levels were applied in each light regime. Morphology, biomass allocation patterns, leaf gas exchange and hydraulic conductance of the whole root system were evaluated. Fertilization treatments produced significant changes in biomass allocation, gas exchange and root hydraulic conductance under both light regimes. In contrast, no differences were found between full sunlight and shade, except for a slight variation in the root:shoot ratio. Photosynthesis rate and WUE increased with fertilization in both light regimes, while E and gs maintained the same values. An opposite trend was observed for root hydraulic conductance, which showed lower values with high fertilization regimes. The results obtained indicate that fertilization is more important, determining high photosynthetic capacity than high hydraulic conductance rates before planting in Pinus canariensis containerized seedlings.     

不同光环境下亚热带常绿阔叶树种和落叶阔叶树种幼苗的叶形态和光合生理特征

由于地球环境的演变,亚热带常绿阔叶林中常有落叶阔叶成分的存在,但从生态角度,其存在的机理尚不清楚.通过比较研究常绿阔叶优势树种大头茶与落叶阔叶树种枫香幼苗的叶形态和光合生理特征对不同光环境(旷地、林窗、林下)的响应,尝试解释落叶成分遗留的基础.结果表明:①枫香具有较小的比叶重(LMA)和较高的光合氮利用效率(PNUE),在高光环境中,并未受到光抑制,具有较高的光合可塑性,尤其在林窗,表现出较大头茶高3倍的光合能力(Pnmax),保证了其在较短的生长季节积累更多的光合产物,增强与常绿树种的竞争力;②常绿阔叶树种大头茶具有较大的LMA,在旷地受到严重的光抑制,将更多的氮用于化学防御中.在林窗和林下具有相对高的Pnmax,生长幅度较广,但在林下将更多的氮投入到比生长更为重要的生存消耗中.而枫香在林下响应表现为Rubisco活性降低,光合受阻;③两树种在林窗均表现出较高的光合适应性,具有最大的光合能力(Pnmax)及合理的氮在光合机构中的分配系数,说明林窗是它们更新的最佳环境.但枫香的光合作用更依赖于光照,而大头茶则更依赖于CO2浓度;④总之,落叶阔叶树种以其较高的形态可塑性和对高光的光合生理可塑性能够在常绿阔叶林种生存、生长,并成为常绿阔叶林中固有成分的主要原因之一.     

不同光强下生长的亚热带树苗的光合-光响应特性的比较

鼎湖山亚热带森林中的优势树种马尾松、荷木、黧蒴和黄果厚壳桂的幼苗,盆栽于100%、40%和16%的自然光下生长1年.利用氧电极离体测定叶片的光合-光响应曲线,结果表明不同树种及同一树种不同生长光强处理之间差异明显.比较最大净光合速率(Amax)、光补偿点、光饱和点、光抑制点及光能利用效率(QUE)等的变化可见,黄果厚壳桂为耐阴植物,对高光强的光合适应潜力为有限,100%的自然光明显抑制其最大同化力;其余3种植物均为喜光植物,其中马尾松的光合作用对遮阴的适应能力较差,而荷木和黧蒴则相对较强.本文还对植物的光合生理特性与其演替状态的联系作了初步探讨.