水分和CO2浓度对冬小麦气孔特征、气体交换参数和生物量的影响

利用可精准控制CO₂浓度([CO₂])的大型人工气候室, 研究了水分亏缺和[CO₂]升高对冬小麦气孔特征、气体交换参数及生物量的影响。结果表明, 水分亏缺导致冬小麦气孔开度减小和气孔空间分布的规则程度降低, 提高[CO₂]能够减缓水分亏缺时气孔开度和气孔分布规则程度的下降幅度。与充分灌溉相比, 不同水分亏缺条件下冬小麦的净光合速率、气孔导度和蒸腾速率均显著降低(P<0.05), [CO₂]仅可缓解轻度亏水对气体交换过程的影响, 该缓解能力随水分亏缺程度的加剧而降低。水分亏缺降低冬小麦生物量, 但[CO₂]升高对水分亏缺时生物量产生的影响不显著(P>0.05)。水分亏缺条件下, 冬小麦通过调整气孔开度和气孔空间分布格局改变叶片的气体交换效率, [CO₂]升高对冬小麦产生的“施肥效应”受土壤水分条件的限制。     

增施CO2对马铃薯植株光合特性及产量的影响

为检验增施CO₂对马铃薯组培苗植株光合特性及微型薯产量的影响,选用马铃薯品种夏坡蒂组培苗为试验材料,于2015年在温室条件下进行了两批次试验。结果表明,增加CO₂浓度可显著增加植株的叶面积、叶片净光合速率和胞间CO₂浓度,且CO₂ 750μmol/mol处理>550μmol/mol处理>CK（空气）,但增加CO₂浓度降低了马铃薯植株叶片气孔导度和蒸腾速率。结果还表明,增施CO₂增加了马铃薯单株结薯数、单个薯重和单株产量,其增幅随CO₂量的增加而增加。上述结果充分证明在温室条件下增施CO₂对加速马铃薯微型薯的繁育有积极作用。     

6个猕猴桃品种的光合特性分析

为筛选优良猕猴桃品种,以2个泰安市本地主栽品种和4个引进品种为试验材料,测定叶片相关生理指标,使用便携式光合作用测定系统测定6个猕猴桃品种的光合日变化、光合作用光响应(PnPAR),分析净光合速率(Pn)、气孔导度(Gs)、胞间CO₂浓度(Ci)、蒸腾速率(Tr)之间的相关性。结果表明,‘徐香’光适应范围为最高,其表观量子效率为0.067,光饱和点为1632μmol/(m²·s),光饱和点与光补偿点差值为1600μmol/(m²·s)。‘泰山1号’净光合速率最大为18.45μmol/(m²·s),光能利用效率最高达到1.26%,均是6个猕猴桃品种中的最高值。综合分析,‘徐香’和‘泰山1号’光合特性最好。以净光合速率、蒸腾速率、气孔导度、胞间CO₂浓度作为变量进行相关性分析,发现气孔导度和蒸腾速率对猕猴桃净光合速率的影响呈极显著正相关,胞间CO₂浓度和净光合速率呈现显著负相关。     

氮素对高大气CO2浓度下小麦叶片光合功能的影响

为探讨高大气CO₂浓度下植物光合作用适应现象的光合能量转化和分配的氮素响应及其对C₃植物光合功能的影响,本试验对盆栽小麦进行2个大气CO₂浓度和2个氮水平的组合处理,通过测定小麦光合气体交换参数、叶绿素荧光参数和叶绿素含量等指标,研究施氮对高大气CO₂浓度下小麦叶片光合功能的影响。结果表明,大气CO₂浓度升高后,低氮处理小麦叶片光合速率发生明显的适应性下调,光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)下降;但高氮叶片则无明显的光合作用适应现象发生。高大气CO₂浓度下低氮叶片光化学速率、PSII线性电子传递速率(J_F)、光合电子流的光化学传递速率(J_C)、Rubisco羧化速率(V_C)和TPU下降,并随生育时期推进其下降趋势更为明显,但高氮叶片的上述参数无显著变化;小麦叶片J_C/J_F、V_C/J_C和V₀ /V_C随氮素水平和大气CO₂浓度的变化无显著变化,表明施氮能提高光合机构对光合能量的传递速率,但对光合能量的分配方向无明显影响。施氮提高小麦叶片氮素和叶绿素含量,并且使高大气CO₂浓度下光合氮素利用效率(NUE)明显增加。大气CO₂浓度升高后,施氮增强光合机构的光合能量运转速率,同化力提高,无明显的光合作用适应现象;由于氮素水平与大气CO₂浓度对小麦叶片的光合能量利用存在明显的交互作用,而且高大气CO₂浓度下施氮使得小麦叶片NUE增加、正常大气CO₂浓度下降低,证明高大气CO₂浓度下施氮对光合作用具有直接的影响。     

高大气CO2浓度下氮素对小麦叶片光合能量分配的调节

探讨了施氮量对高大气CO₂浓度下小麦功能叶光合能量传递与分配的影响,进而明确氮素对小麦叶片光合作用适应性下调的能量分配调节作用。采用开顶式气室盆栽法,通过测定小麦拔节期和抽穗期不同大气CO₂浓度和施氮水平下的叶氮浓度、光合速率–胞间CO₂浓度(P_n–C_i)响应曲线和荧光动力学参数,测算光合电子传递速率和分配去向。与在正常CO₂浓度(400 μmol mol^-1)条件下相比,在高大气CO₂浓度(760 μmol mol^-1)下,小麦叶氮浓度显著下降,N200处理(200 mg kg^-1)叶片抽穗期叶氮浓度的下降幅度较拔节期高335.7%。N200处理较N0处理(0 mg kg^-1)提高小麦叶片光适应下PSII反应中心最大量子产额(F_v′/F_m′)、光化学效率(Φ_PSII)和开放比例(q_P),降低非光化学猝灭系数(NPQ)。高大气CO₂浓度下,小麦叶片光化学反应的非环式光合电子传递速率(J_c)和Rubisco羧化速率(V_c)显著升高,而光呼吸的非环式光合电子传递速率(J_o)和Rubisco氧化速率(V_o)明显降低;施氮使J_c、J_o、V_c和V_o值均呈上升趋势,而且J_c和V_c达到显著差异。高大气CO₂浓度下J_o/J_c和V_o/V_c显著降低,施氮后小麦拔节期叶片J_o/J_c和V_o/V_c降低,但抽穗期J_o/J_c升高而V_o/V_c无明显变化。叶氮浓度与小麦叶片J_c、J_o和V_o均呈显著线性正相关,而且高大气CO₂浓度下小麦叶片J_c、J_o和V_o对氮浓度的敏感性降低。高大气CO₂浓度下,小麦叶片PSII反应中心开放比例增加,非光化学耗能降低,更多的光合电子进入光化学过程;施氮后使小麦叶氮浓度增加,提高光合能力,改变了能量分配,这是高氮条件下光合作用适应性下调被缓解的一个关键因素。     

大气CO_2倍增条件下冬小麦气体交换对高温干旱及复水过程的响应

探究大气CO_2浓度倍增条件下冬小麦气体交换参数对高温干旱及复水过程的生理响应机制,有助于提高生态过程模型的模拟精度,更加准确地预测全球气候变化对农田生态系统初级生产力及其生态服务功能的影响。利用4个可精准控制CO_2浓度和温度的大型人工气候室,研究了CO_2浓度倍增条件下高温干旱及复水过程对冬小麦气孔特征和气体交换参数的影响。结果表明, CO_2浓度倍增(E)导致冬小麦远轴面气孔密度增加、气孔宽度减小、气孔空间分布规则程度降低,但提高叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)。高温干旱(HD)使叶片气孔长度、密度、周长和面积减小,导致叶片气体交换参数均显著下降。然而,高CO_2浓度及高温干旱(EHD)导致气体交换参数下降幅度相对较小,表明高CO_2浓度对高温干旱具有一定的缓解作用。此外,干旱复水后,不同处理条件下冬小麦叶片气体交换参数均有所升高,但高温干旱下叶片的气体交换参数仍未能恢复到对照水平,暗示光合器官可能在高温干旱时遭到损伤和破坏。     

高粱光合特性、水分利用效率鉴定及产量综合性分析

为筛选出光合能力强、水分利用效率高,植株形态好,产量高的品种。以16份高粱材料为基础,在自然条件下利用LI-6400光合仪测定其叶片的光合参数,测量株高、茎粗、产量并进行综合评价分析。结果表明：‘吉杂210’的光合特性和水分利用效率综合性状表现较好,‘吉杂210’的净光合速率(Pn)、气孔导度(G_s)、胞间CO₂浓度(C_i)均高于其他高粱品种,其中净光合速率和胞间CO₂浓度的变幅为22.50～36.48μmo CO₂·m^-2·s^-1和51.11～122.52μmol CO₂·m^-2·s^-1。‘吉杂210’的千粒重和产量最高,分别为37.60 g和11916.67 kg/hm²,明显高于其他高粱品种;‘吉杂247’最高,‘吉杂243’最矮,‘吉杂236’的茎秆最粗,且显著高于其他材料。相关分析表明,净光合速率、气孔导度(G_s)、...     

CO2浓度升高条件下不同氮素水平对小叶章光合特性和生长的影响

为阐明大气CO₂浓度升高和不同氮素水平对湿地植物光合生理特性和生长的影响,本研究以三江平原湿地优势植物小叶章(Calamagrostis angustifolia)为研究对象,通过野外原位控制试验,利用开顶式气室(OTC)模拟环境大气CO₂浓度变化,设置E₀(380 ±20 µmol/mol)、E₁(550 ±20 μmol/mol)和E₂(700 ± 20 μmol/mol)3个CO₂浓度;在每个OTC内设置 N₀(0 g N/m²)、N₁(4 g N/m²)和N₂(8 g N/m²)3个氮素水平。结果表明,N₀条件下,与E₀处理相比,E₁和E₂处理（72 天）后小叶章叶片净光合速率分别降低11%和12%(P<0.05),其叶片可溶性蛋白含量、氮素含量（CO₂熏蒸72 天）、小叶章株高（CO₂熏蒸86 天）均显著低于E₀处理(P<0.05);N₁条件下,与E₀处理相比,E₁和E₂处理（72 天）后小叶章叶片净光合速率降低5%(P>0.05)和10%(P<0.05),其叶片氮素含量(P<0.05)、小叶章株高均低于E₀处理;N₂条件下,E₁和E₂处理（72 天）小叶章净光合速率均呈稍增加的趋势(P>0.05),其叶片可溶性蛋白含量显著增加(P<0.05),氮素含量和小叶章株高无显著变化(P>0.05)。N₀、N₁和N₂条件下,CO₂浓度升高均显著增加了小叶章叶片可溶性糖含量。本研究表明长期CO₂浓度升高可能通过降低小叶章叶片光合酶活性,进而降低了其净光合速率,而施加高浓度的氮肥可以缓解长期高CO₂浓度对湿地植物光合及生长的负面影响。     

气孔在葱莲不同器官分布的初步研究

以新鲜葱莲植株为材料,用光学显微镜对其花、花茎、鳞茎、叶、果实、种子和根等部位的表皮进行研究,对花瓣上表皮、花瓣下表皮、花茎的表皮、外果皮、叶近轴面和叶远轴面气孔指数、气孔密度和保卫细胞面积分别进行比较,并分别对花瓣和叶的气孔密度与保卫细胞面积进行相关性分析。结果表明,只有根上未见到有气孔分布。除了在葱莲的叶和花茎等常规部位发现有气孔分布外,花瓣、雄蕊、雌蕊、子房、花梗、花茎、鳞片、果实和种子上均有气孔分布。气孔呈半月形,无副卫细胞。葱莲叶片近轴面的气孔指数和气孔密度显著大于远轴面(P0.05)。花茎和叶上的气孔指数和气孔密度显著大于花瓣和果实(P0.05)。外果皮的气孔指数和气孔密度最小。叶远轴面的保卫细胞面积最大(P0.01),花瓣下表皮的保卫细胞面积最小(P0.01)。花瓣的气孔密度和保卫细胞面积之间的相关性不显著(r=0.089,P0.05),而叶片的气孔密度和保卫细胞面积呈极显著负相关(r=-0.535,P0.01)。     

干旱胁迫对吊兰生理特性及光合作用的影响

以盆栽吊兰(Chlorophytum comosum)为材料,研究了自然干旱胁迫对吊兰生理特性及光合作用的影响。结果表明,(1)自然干旱胁迫下,随着土壤相对含水量的降低,吊兰叶片失水发生内卷或折叠至枯萎,叶片相对含水量降低,叶片中过氧化氢(H₂O₂)和超氧阴离子(O₂^-·)积累、叶片相对电导率(REC)升高,质膜遭到系统破坏,质膜过氧化。(2)吊兰的净光合速率(P_n)、气孔导度(G_s)和胞间CO₂浓度(C_i)均随着干旱胁迫程度的增加而不断降低,表明吊兰在干旱胁迫下P_n下降的主要是由气孔限制造成。(3)干旱胁迫下,吊兰的PSⅡ的最大光化学效率(F_v/F_m)和实际光化学效率(Φ_PSⅡ)呈下降趋势,初始荧光(F_o)和非光化学猝灭系数(qN)在第0～24天呈上升趋势,能以热耗散的形式来避免或减轻光能过剩对其系统的...     

散射光和直射光对高粱叶片光合功能的影响

C₄等面叶作物背腹侧结构相似并分别暴露在散射光和直射光下。为阐述散射光和直射光对其光合功能的驱动作用,以高粱为材料,研究了散射光和直射光对叶片背腹侧光合功能的影响。结果表明,高粱叶片背腹侧解剖结构相似,其光谱学特性差异很小, 与近轴侧相比,远轴侧的气孔密度、气孔下腔面积、维管束鞘细胞与叶肉细胞接触面积较大; 在相同直射光下近、远轴侧均具有较高的光合速率, 在近轴侧照光同时用PE膜封闭叶片受光侧气孔,观察到远轴侧在叶片自身透射光下能够维持较高的净光合速率;相反,近轴侧在自身透射光下光合速率很低; 自然光照条件下一天内直射光和散射光强度差异很大,大部分时间的散射光强度明显低于远轴侧光补偿点。由此认为,高粱远轴侧光合作用主要由自身透射光驱动,散射光作用很小,该特性是对光环境的适应。这对田间等面叶作物生产管理、生态系统生产力的研究和高光效育种有重要意义。     

Genetic variation in stomatal characteristics and behaviour,water use and growth of five Vicia faba L. genotypes under contrasting soil moisture regimes

Summary Five genotypes of Vicia faba L. with contrasting frequencies were grown in a controlled environment in soil moisture regimes of 100%, 78% and 61% of field capacity. Growth, water use and leaf conductance characteristics were measured. Stomata were more frequent on abaxial than adaxial surfaces, the abaxial/adaxial ratio ranging from 1.12 to 1.34. There were significant (P<0.001) correlations between calculated stomatal conductance, based on measurements of stomatal frequency and length, and leaf conductance measured with a diffusion porometer, in the two higher soil moisture treatments. In the 100% regime only, abaxial stomata opened wider than adaxial. Ranking of the genotypes for leaf conductance and plant transpiration was similar in all three regimes with large leaved types having the lowest conductance and greatest water use efficiency. Growing plants with reduced soil moisture availability improved water use efficiency, the ranking for which was also similar in all treatments. Relative growth rate and net assimilation rate were greatest with full watering, less in the 78% and least in the 61% regime. Leaf area ratio was less affected by available soil moisture and only in some genotypes.     

Photosynthetic responses in spring wheat grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment ‘ESPACE-wheat’

Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO₂ concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO₂ for a range of N application regimes, O₃ concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 μmol mol⁻¹ CO₂ at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO₂ before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO₂ after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO₂ therefore appears to occur only slowly, consistent with a response to changes in sink–source relationships, rather than a direct response. Effect of elevated CO₂ on stomatal conductance was much more variable between sites and treatments, but on average was decreased by ˜10% at 650 compared with 350 μmol mol⁻¹ CO₂. Carboxylation capacity of flag leaves was decreased by growth at elevated O₃ both before and after anthesis, regardless of CO₂ concentration.     

Transpiration Dynamics in Cadmium-Treated Soybean (Glycine max L.) Plants

Soybean ( Glycine max L.) plants, cv Richland, were grown during 30 days in a nutrient solution. After this period the plants were treated with a 50 μM Cd(NO₃)₂ solution. Sap flow rate and stomatal conductance were monitored during 4 consecutive days; at the end of this period relative water content and stomatal width and length were determined on fully expanded leaves. On the second day from the Cd treatment sap, flow rate and stomatal conductance in the treated plants were reduced to 60% of the control plants. Stomatal conductance kept on decreasing up to the fourth day. Cadmium decreased the leaf relative water content and the reduction in the stomatal closure was supported by an increase in the L/W ratio of the stomata. Root water uptake should be the primary mechanism reduced by Cd stress in soybean, and this reduction is consistent with the decrease in transpiration rate and with the stomatal closure.     

气孔在辣椒(Capsicum annuum L.)子叶和下胚轴上的动态变化

以辣椒幼苗(Capsicum annuum L.)为材料,研究了辣椒生长发育过程中子叶的上、下表皮和下胚轴上、下端1 cm处的气孔密度及表皮细胞密度的动态变化。结果表明:(1)辣椒的气孔由肾形保卫细胞组成,无副卫细胞;子叶的表皮细胞呈无规则形,下胚轴的表皮细胞呈长方形或椭圆形;(2)辣椒子叶上、下表皮的气孔密度和表皮细胞密度分别在辣椒种子出芽后第6天和第3天达到最大,之后随子叶的生长逐渐减小,下表皮的气孔密度和表皮细胞密度明显大于上表皮的;(3)辣椒下胚轴上、下端1 cm处的气孔密度随下胚轴的生长变化不明显,但是表皮细胞密度随下胚轴的生长逐渐减小,下胚轴上端的气孔密度和表皮细胞密度明显的大于下胚轴下端的。     

通过外源MeJA抑制H_2O_2积累提高烟草的耐冷性

茉莉酸甲酯(MeJA)是可参与多种生理生化过程的激发子,为探究外源MeJA对低温环境下烟草幼苗的影响,以烟草品种"豫烟10号"为材料,在其六叶一心时用4个不同浓度(1、10、100和1000μmol L~(–1) MeJA)进行喷施处理3d后,再进行低温处理,同时以正常温度和低温处理作为阳性和阴性对照。分析各处理的长势指标、相对电解质渗透率、光合色素含量、抗氧化酶活性以及激素含量。结果表明:在10μmol L~(–1)茉莉酸甲酯处理下能降低低温对烟草幼苗的损伤。然后在材料和时期不变的情况下,进行DPI、10μmol L~(–1) MeJA以及DPI+MeJA处理以低温处理为对照,测定了H_2O_2、O~(2–)、CAT、MDA以及ASA-GSH循环的含量。证明在外源茉莉酸甲酯协同低温的处理下,烟草植株中的H_2O_2主要作为毒害分子而非第二信使存在。     

Growth and marketable-yield responses of potato to increased CO2 and ozone

Central to the CHanging climate and potential Impacts on Potato yield and quality project (CHIP) was the consideration of the potential impacts of ozone and CO₂ on growth and yield of future European Potato crops. Potato crops, cv. Bintje, were exposed to ambient or elevated ozone; targeted daily average, 60 nl l⁻¹ for 8 h, and ambient or elevated CO_2; targeted 680 μl l⁻¹ averaged over the full growing season, in open top chambers (OTCs) at six European sites in 1998 and 1999, or to elevated CO₂ (550 μl l⁻¹) in Free Air Carbon dioxide Enrichment facilities (FACE) at two sites in both years. Some OTC experiments included 550 μl l⁻¹. Above and below ground biomass were measured at two destructive harvests; at maximum leaf area (MLA) and at final-harvest. Final-harvest fresh weight yields of marketable-size tubers, >35 mm diameter, from ambient conditions ranged from 1 to 12 kg m⁻². There was no consistent (P>0.1) CO₂×O₃ interaction for growth or yield variables at either harvest. No consistent effects of ozone were detected at the maximum-leaf-area harvest. However, at final harvest, ozone had reduced both above-ground biomass and tuber dry weight (P<0.05), particularly of the largest (>50 mm) size class. These yield losses showed linear relationships both with accumulated ozone exposure; AOT40 expressed as nl l⁻¹ h over 40 nl l⁻¹, and with yields from chambered ambient-ozone treatments (P<0.05) but, because of partial confounding between the treatment AOT40s and the ambient-ozone yields in the data, the two relationships were not completely independent. Yields from ambient-ozone treatments, however, explained a significant (P<0.01) amount of the residual variation in ozone effects unexplained by AOT40. When averaged over all experiments, mean dry weights and tuber numbers from both harvests were increased by elevated CO₂. Only green leaf number at the MLA harvest was reduced. The CO₂ responses varied between sites and years. For marketable-size tubers, this variation was unrelated to variation in ambient-CO₂ treatment yields. Yield increases resulting from the 680 μl l⁻¹ and 550 μl l⁻¹ treatments were similar. Thus elevating [CO₂] from 550 to 680 μl l⁻¹ was less effective than elevating [CO₂] from ambient to 550 μl l⁻¹. On average, CO₂ elevation to 680 μl l⁻¹ increased the dry weight of marketable-size tubers by about 17%, which far exceeded the average ozone-induced yield loss of about 5%. The net effect of raising CO₂ and O₃ concentrations on the European potato crop would be an increase marketable yield.