小麦根系活力变化与叶片衰老的研究

对小麦根系活力、叶片叶绿素含量和光合速率变化的田问实验结果表明,根系活力的衰退早且快于叶片叶绿素含量和光合速率的衰退;根系活力和叶片光合速率呈正相关关系(r=0．8006)．拔节期追施氮肥,改善根际营养条件后,叶片的光合速率、根系活力明显提高,叶片中ABA含量降低,ZRs升高,SOD活性增加,MDA的高峰期比对照推迟8～10d,说明根系活力变化与地上部叶片的衰老密切相关,改善根际营养,提高生育前期的根系活力有助于延缓地上部分的衰老．     

银杏叶片叶绿体光能转换特性的变化

要以5年生雌、雄银杏为材料,研究了自然生长条件下银杏叶绿体光能转换特性的动态变化规律。结果表明：连体叶片的净光合速率在叶片生长40d达到最大值;随着叶片的展开,叶片叶绿素含量逐渐上升;叶绿体ATP含量伴随着光合磷酸化活力变化在叶片生长初期含量逐渐上升,叶片生长65d时最大;Mg^2＋、Ca^2＋-ATPase活力在叶片生长初期逐渐下降,生长50d后开始逐渐上升。实验结果也显示雌、雄银杏叶绿体光能转换能力比较相似,没有较大差异。     

花粒期光照对夏玉米光合特性和叶绿体超微结构的影响

在大田条件下,以夏玉米品种‘登海605’为试验材料,研究花粒期不同光照强度(正常光照、开花至收获期遮阴和开花至收获期增光)对夏玉米叶片光合、荧光性能和叶绿体超微结构的影响.结果表明:与对照相比,花粒期遮阴影响叶绿体排布及内部结构发育,基粒个数和基粒片层数均有不同程度减少,叶片的净光合速率、蒸腾速率、气孔导度、叶绿素含量下降,PSⅡ反应中心的实际光化学效率和最大光化学效率降低,非光化学淬灭系数数值增加,导致产量降低;增光后叶绿体结构良好,基粒片层排列紧致、清晰且数量增加,PSⅡ反应中心的实际光化学效率增加,净光合速率、蒸腾速率、气孔导度、叶绿素含量上升,叶片光合性能增强,产量增加.即花粒期遮阴破坏了夏玉米叶片叶绿体超微结构,降低了叶片光合能力,产量下降;花粒期增光增加了叶肉细胞中叶绿体的基粒和基粒片层,导致基粒片层排列紧密有序,有利于增加作物产量潜力.     

银杏叶片叶绿体光能转换特性的变化

以5年生雌、雄银杏为材料,研究了自然生长条件下银杏叶绿体光能转换特性的动态变化规律。结果表明：连体叶片的净光合速率在叶片生长40 d达到最大值;随着叶片的展开,叶片叶绿素含量逐渐上升;叶绿体ATP含量伴随着光合磷酸化活力变化在叶片生长初期含量逐渐上升,叶片生长65 d时最大;Mg²⁺、Ca²⁺ ATPase活力在叶片生长初期逐渐下降,生长50 d后开始逐渐上升。实验结果也显示雌、雄银杏叶绿体光能转换能力比较相似,没有较大差异。     

铁皮石斛叶色突变体的叶绿体超微结构、光合色素和叶绿素荧光特性的研究

以铁皮石斛(Dendrobium officinale Kimura et Migo)(‘TP35’)经自然突变的白绿杂色突变体(‘TP-MA’)和太空诱变的绿黄杂色突变体(‘TP-MG’)为材料,研究不同光照强度(0、50、100μmol·m^-2·s^-1)处理后,植株叶片的叶绿体超微结构、光合色素含量以及叶绿素荧光动力学参数的变化规律,并阐明叶色突变体与正常植株光合特性的差异。结果显示,‘TP-MA’和‘TP-MG’的叶绿体形态均发生了一定程度的缺失,且叶绿体分布不均匀、无规则,基粒片层结构不完整且排列疏松,基本与其表型性状相一致。‘TP-MA’光合色素的含量和叶绿素荧光参数F v/F m、ΦPSⅡ及F v′/F m′等显著低于‘TP35’,但非光化学淬灭系数(NPQ和q P)则相对较高;‘TP-MG’的光合色素含量及叶绿素荧光参数均低于‘TP35’,但差异不显著,且对较强的光照(100μmol·m^-2·s^-1)条件具有一定的适应性。研究结果表明不同光强处理后,铁皮石斛叶色突变体的叶绿体结构和光合生理指标均发生了不同程度的变化,且对植株的叶绿素含量及荧光参数产生一定影响,过低和过高的光照强度均不利于植株的正常生长。     

南城淮山脱毒苗移栽驯化期的光合生理

为了解南城淮山脱毒苗移栽驯化期的光合生理,本研究对其移栽驯化期的叶绿素含量以及其光合特性和叶绿素荧光参数进行测定和统计分析。结果表明,南城淮山脱毒苗在移栽驯化初期具有较高的叶绿素含量;随着移栽驯化时间延长,脱毒苗的叶绿素含量也显著提高;当移栽驯化时间达到10 d时,脱毒苗的叶绿素含量达到最高值;但当移栽驯化时间超过10 d时,脱毒苗的叶绿素含量则显著下降。脱毒苗在移栽驯化期间的叶绿素含量显著高于其带毒苗。脱毒苗移栽驯化期内的净光合速率(Pn)、气孔限制值(Ls)、水分利用效率(WUE)、瞬时羧化速率(CUE)、初始荧光(Fo)、暗适应下最大荧光(Fm)、暗适应下PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在光化学效率(Fv/Fo)、光适应下PSⅡ实际光化学效率(ФPSⅡ)、光适应下PSⅡ最大光化学效率(Fv'/Fm')、光化学荧光猝灭系数(q P)先增后降;蒸腾速率(Tr)和气孔导度(Gs)显著下降;胞间CO2浓度(Ci)和非光化学猝灭系数(q N)先降后升。脱毒苗的Pn、Tr、Gs、Ls、WUE、CUE、Fo、Fm、Fv/Fm、Fv/Fo、ФPSⅡ、Fv'/Fm'、q P均显著高于带毒苗,而其Ci和q N显著低于带毒苗。因此,南城淮山脱毒苗老叶在移栽驯化期第10天具有较强的光合效率,随后其光合效率随着移栽驯化时间的延长而显著下降,并逐渐由新生叶的光合作用所代替。南城淮山脱毒苗的光合效率显著高于带毒苗,有利于积累更多的光合产物,从而实现增产。本实验结果为南城淮山脱毒苗的移栽驯化及其大田种植提供了理论基础。     

不同小麦种叶片光合特性及叶绿体超微结构的比较

小麦野生一粒、粗山羊草及中国春苗期叶片全展时的光合速率以野生一粒最高,中国春最低。而维持高水平叶绿素含量及光合速率的持续时间却以中国春最长,野生一粒最短。叶片衰老过程中,3种小麦叶绿体的超微结构变化模式相似,但变化进程明显不同。六倍体的中国春小麦叶绿体衰老速度最慢,二倍体的野生一粒小麦最快。     

3种石斛光合作用和叶绿素荧光特性的比较研究

以美花石斛、春石斛和铁皮石斛为材料,对它们的叶片进行光合作用、叶绿素含量和叶绿素荧光等参数的测定.结果表明:3种石斛的光饱和点都低于300 μmol·m-2·s-1,且美花石斛具有较高的净光合速率和较低的光饱和点,容易引起光抑制;美花石斛的羧化效率高于春石斛和铁皮石斛,其净光合速率随着CO2浓度的升高而迅速升高,并在CO2浓度达到500 μmol·m-2·s-1时达到最大值;美花石斛的非循环电子传递速率(ETR)、实际光化学反应量子效率(Yield)和光化学猝灭系数(qP)都明显高于铁皮石斛和春石斛,而春石斛具有较高的非光化学猝灭系数(qN),其光合机构的自我保护能力较强;美花石斛的叶绿素a、叶绿素b以及总叶绿素含量都较低.研究发现,3种石斛的光饱和点均比较低,具有石斛喜阴的生活习性,都表现出对密林和悬崖等独特生长环境的适应,并以美花石斛的这种特性更为突出.     

UV-B辐射增强对芦苇光合生理及叶绿体超微结构的影响

在UV-B辐照增强条件下,研究不同辐照梯度对芦苇光合特性、光合色素含量及叶绿体超微结构的影响. 结果表明: 与自然光照相比,UV-B辐照增强显著降低芦苇叶片净光合速率、气孔导度、蒸腾速率,且随辐照强度增大,降低程度加剧,胞间CO₂浓度升高,光合效率显著降低;与自然光照相比,UV-B辐照增强显著降低芦苇叶片光合色素含量(包括叶绿素a、叶绿素b、总叶绿素和类胡萝卜素),且随辐照强度增大,降低程度加剧;UV-B辐射增强条件下,叶绿体超微结构遭到破坏,表现为叶绿体结构变形,类囊体片层排列稀疏紊乱、膨胀甚至模糊不清,并且UV-B辐射强度越大,损伤越大,高强度UV-B辐射对叶绿体超微结构的影响大于低强度辐射.     

兰科菌根真菌对铁皮石斛光合性能及pepc基因表达的影响

为了阐明兰科菌根真菌对铁皮石斛光合作用的影响及机制,采用盆栽方式研究了兰科菌根真菌对铁皮石斛幼苗生长的影响,并分析了叶片中叶绿素含量、光合参数、叶绿素荧光参数以及pepc基因表达的变化。结果表明：（1）兰科菌根真菌促进了铁皮石斛幼苗生长,接种兰科菌根真菌的铁皮石斛的株高、根重、茎叶重和总生物量分别是未接种对照组的1.21、1.54、1.71和1.68倍;而且可显著提高叶片中叶绿素含量、叶片净光合速率（P_n）、蒸腾速率（G_s）和气孔导度（T_r）。（2）接种兰科菌根真菌的铁皮石斛叶片潜在光化学效率（F_v/F₀）、最大光化学效率（F_v/F_m）、光化学猝灭系数（q_P）、非光化学猝灭系数（q_N）、实际光化学反应量子效率（Yield）和表观光合电子传递速率（ETR）均高于未接种对照组。（3）菌根真菌能促进pepc基因的表达,增强PEPC活性,提高铁皮石斛叶片的光合碳同化能力。研究表明,菌根的形成可以提高铁皮石斛叶片光合性能和pepc基因的表达水平,促进铁皮石斛幼苗的生长。     

Light Affects the Chloroplast Ultrastructure and Post-Storage Photosynthetic Performance of Watermelon (Citrullus lanatus) Plug Seedlings

Watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] plug seedlings were stored at 15°C in the light at a photosynthetic photon flux density of 15 µmol·m⁻²·s⁻¹ or in darkness for 6 days, to evaluate their chloroplast ultrastructure, and associated photosynthetic characteristics. Storage in the dark caused swelling, disordered granal arrangement, and starch grain disappearance in the chloroplasts. In contrast, the chloroplasts stored in the light were relatively normal. As a result, the light-stored seedlings had a significantly higher chlorophyll content, Fv/Fm, and Pn than did dark-stored seedlings. Regardless of whether the seedlings were stored in light or darkness, the Gs and Ls of the seedlings significantly decreased, while the Ci obviously increased when the Pn decreased after 6 days of storage. This result suggests that the decreased Pn is not solely a stomatal effect, as the effects on the chloroplasts contributed to this photosynthetic inhibition. Six days after transplanting, seedlings that were stored in the light or darkness for 2 or 4 days showed complete recovery of chloroplast ultrastructure, chlorophyll content, Fv/Fm, Gs and Pn. When the storage period increased to 6 days, the dark-stored seedlings had a significantly lower Fv/Fm and Pn than the light-stored and control seedlings 6 days after transplanting, which was mainly ascribed to incomplete recovery of chloroplast ultrastructure. Furthermore, the light-stored seedlings exhibited a significantly higher shoot dry weight during storage and a higher percentage dry weight increase after transplanting than the dark-stored seedlings. These effects were enhanced by prolonged storage (4 to 6 days). This study demonstrated that dim light during storage is beneficial for maintaining chloroplast ultrastructure as well as photosynthetic efficiency in watermelon seedlings, thus contributing to the rapid recovery of post-storage photosynthetic performance, which ensures the transplant quality of the seedlings after removal from storage.     

Effect of Anatase Nanoparticles (TiO2) on Parsley Seed Germination (Petroselinum crispum) In Vitro

Nano priming is a new method for the increase of seedling vigor and improvement of germination percentage and seedling growth. The experiments to evaluate the effect of different concentrations of nano-anatase on germination parameters of parsley as a completely randomized design with five replications were performed in a tissue culture laboratory of the Department of Horticulture, Shahid Chamran University of Ahvaz. In addition, nano-anatase at four concentrations (10, 20, 30, and 40 mg/ml) was added to the Murashige and Skoog medium. At the end of the experiment, the percentage of germination, germination rate index, root and shoot length, fresh weight of seedlings, vigor index, and chlorophyll content were evaluated. The results showed that an increase in the concentration of nano-anatase caused a significant increase in the percentage of germination, germination rate index, root and shoot length, fresh weight, vigor index, and chlorophyll content of seedlings. The best concentration of nano-anatase was 30 mg/ml.     

水杨酸和茉莉酸甲酯对丹参幼苗叶片显微结构、光合及非结构糖积累的影响

研究了水杨酸(SA)和茉莉酸甲酯(MeJA)处理对丹参(Salvia miltiorrhiza Bunge)幼苗叶片显微结构、叶片光合能力及幼苗中非结构糖积累的影响.结果显示:SA处理增加了丹参幼苗叶片气孔密度;叶肉细胞排列紧密、体积减小,叶肉细胞内叶绿体数目减少,但叶绿体体积增大,叶绿体基粒片层结构的数目增加;叶片中叶绿素a、b含量、叶气孔导度、蒸腾速率以及净光合速率均增加;同时,幼苗根中和叶片中酸性转化酶活性降低,幼苗地上部分蔗糖含量及可溶性糖总量显著高于对照.MeJA处理减少了叶片气孔密度,气孔发育畸形;叶肉细胞间隙增大,栅栏细胞层数减少,叶肉细胞内叶绿体数目减少,叶绿体体积减小,叶绿体基粒片层结构被破坏;叶片中叶绿素a及类胡萝卜素含量、叶片的净光合速率低于对照,叶气孔导度、蒸腾速率增强;同时,幼苗根中及叶中酸性转化酶活性增加,幼苗根中蔗糖含量及可溶性糖总量显著低于对照.可见,SA处理能促进植物叶片显微结构发育,增强叶片光合能力,抑制蔗糖降解并促进蔗糖积累;而MeJA处理则破坏了植物叶片显微结构,降低了叶片光合能力,促进了蔗糖降解并减少蔗糖积累.     

干旱胁迫下亚精胺对玉米幼苗抗旱性影响的生理生化机制

为探究外源亚精胺(Spd)在增强玉米干旱胁迫耐受性中的作用,以‘先玉335’(干旱不敏感型)和‘丰禾1’(干旱敏感型)为试验材料,采用营养液水培法,研究了15%聚乙二醇(PEG-6000)模拟干旱胁迫下,外源Spd (0.1 mmol·L^-1)对玉米幼苗生长、光合特性、叶绿素含量、渗透调节物质、活性氧生成、膜质过氧化及根系活力的影响.结果表明:干旱胁迫下,外源Spd处理可显著促进干旱胁迫下玉米幼苗的生长;提高叶绿素含量、净光合速率(P_n)、气孔导度(g_s)、蒸腾速率(T_r)和水分利用效率(WUE),减缓‘丰禾1’叶片中胞间CO₂浓度(C_i)的升高,有效减轻干旱胁迫对玉米幼苗叶片光合作用的气孔限制和非气孔限制;增加脯氨酸和可溶性糖的含量;降低O₂^-·生成速率、H₂O₂和丙二醛(MDA)含量、细胞膜透性,有效缓解了胁迫对膜的伤害;增强幼苗根系活力;其中干旱敏感品种‘丰禾1’变化幅度大于耐旱品种‘先玉335’.表明在干旱胁迫下,外源Spd能促进玉米幼苗对光能的捕获与转换,增强光合作用,促进幼苗的生长,并能够通过减少玉米幼苗体内活性氧的产生,增加渗透调节物质的积累以稳定细胞膜系统,提高根系活力,从而增强幼苗对干旱逆境的适应性,且对干旱敏感品种‘丰禾1’的效果更显著.     

干旱胁迫下尖果沙枣幼苗的根系活力和光合特性

以尖果沙枣1年生实生苗为材料,研究了自然干旱时不同土壤相对含水量对幼苗叶片细胞质膜相对透性、叶片相对含水量、根系活力、光合色素含量和光合参数等指标的影响.结果表明:土壤相对含水量从70%(CK)降到40%时,幼苗根系活力和净光合速率均逐渐上升并达到最大值,分别为1178μg.g-1.h-1和21.9μmol.m-2.s-1;光合色素含量稳步上升;蒸腾速率和水分利用效率均保持稳定;叶片细胞质膜相对透性保持较低水平.土壤相对含水量从40%降到20%时,幼苗叶片相对含水量仍在50%以上,叶片细胞质膜相对透性仍保持较低水平;根系活力和光合色素含量仍较高;但其他光合参数开始缓慢下降.土壤相对含水量从10%降到5%时,幼苗叶片细胞质膜相对透性急剧上升;叶片相对含水量、根系活力、总叶绿素含量、光合参数均极显著下降;而土壤相对含水量为10%时幼苗表现出最高的水分利用效率.尖果沙枣土壤相对含水量最好控制在40%~50%,其1年生实生苗的永久萎蔫系数为4.3%(土壤相对含水量).     

Effect of Heat Stress on Photosynthetic Activity and Chloroplast Ultrastructure in Correlation with Endogenous Cytokinin Concentration in Maize Seedlings

The effect of heat stress (47.5?C for 2 min given to the roots)on photosynthetic activity and chloroplast ultrastructure wasstudied in correlation with the endogenous cytokinin concentrationin maize (Zea mays L. "Fronica") seedlings. Shoot and root growth were visibly inhibited by the heat treatment.In etiolated leaf segments there was a clear-cut inhibitionof photosynthetic activity, chlorophyll accumulation and chloroplastdevelopment. This inhibition was reversible by benzyladenine.In green tissue heat stress only affected photosynthetic activityand chlorophyll accumulation. Again this inhibition could bereversed by benzyladenine. In the primary leaves of green seedlings heat stress loweredcytokinin concentration severely; in etiolated leaves no effectof heat stress could be observed, since the cytokinin concentrationwas below the detectable level. Our results provide an indication for a correlation betweenhormonal control and chloroplast biogenesis. (Received July 5, 1984; Accepted October 12, 1984)     

Changes in photosynthetic apparatus of mustard (<Emphasis Type="Italic">Sinapis alba</Emphasis>) cotyledons following cycloheximide and kinetin treatments

Biochemical and accompanying structural characteristics of the photosynthetic process were studied in mustard seedlings cultivated on medium with increasing concentrations of cycloheximide alone as well as in combination with various kinetin concentrations. After 7 days of cultivation the contents of total chlorophyll, carotenoids and content of Rubisco in mustard cotyledons were determined. The content of chlorophyll pigments and carotenoids decreased in dependence of cycloheximide concentration. Following antibiotic treatment the content of both Rubisco subunits markedly decreased. In addition cycloheximide caused disturbance in mesophyll organization and chloroplast ultrastructure. Kinetin applied with cycloheximide increased the amount of photosynthetic pigments as well as of Rubisco, compared to the cycloheximide alone. In the seedlings treated with cycloheximide+kinetin the structure of leaf mesophyll and chloroplast membrane system was similar to control. Our results indicate that kinetin diminished the negative effects of cycloheximide on photosynthetic pigments and Rubisco as well as on the structural traits of the cotyledons.     

外源激素对脱毒马铃薯扦插苗生长及生理效应研究

以‘早大白’马铃薯脱毒苗为试验材料,通过人工温室苗床栽培探讨外源激素萘乙酸(NAA)、吲哚丁酸(IBA)和硼酸生根处理对扦插脱毒苗生长和生理特征的影响,为马铃薯微型薯的实际生产提供理论依据。结果显示:(1)外源激素生根处理较对照扦插苗根系长势好,根活力、根系可溶性蛋白含量增加。(2)外源激素生根处理较对照脱毒扦插苗光合速率提高、叶绿素含量增加,光合物质的形成与积累增多。(3)外源激素生根处理较对照叶片SOD、POD、CAT活性和游离氨基酸含量均表现出不同程度的上升,MDA含量下降,衰老减缓。(4)外源激素生根处理有利于小区产量和单株结薯数的增加。研究表明,不同外源激素生根处理可改善脱毒马铃薯扦插苗农艺性状和生理指标,并以NAA 100mg/L+IBA 50mg/L+硼酸17.5mg/L配方处理植株的长势最好,叶绿素含量、保护酶活性及游离氨基酸含量最高,净光合速率大、小薯膨大速度快且单株结薯数量及产量增加显著,更利于发挥脱毒薯的增产优势。     

连作土壤中施加球毛壳ND35菌肥对杨树生理特性的影响

在山东农业大学林学实验站杨树连作土壤中施加不同剂量(0.17、0.33、0.67、1.00、1.33和1.67 g·kg^-1)的球毛壳ND35菌肥,测定不同处理下一年生杨树叶片的光响应过程、叶绿素荧光以及叶黄素循环等光合生理生化指标,研究球毛壳ND35菌肥对杨树根系和光合生理性能的影响.结果表明: 随连作土壤中菌肥含量的增加,杨树叶片的叶绿素含量(Chl)呈增加趋势,电子传递速率(ETR)、净光合速率(P_n)、量子效率(Φ)、硝酸还原酶(NR)活性以及根系活力等生理指标均呈先增加后降低的趋势,依赖于叶黄素循环的光合热耗散呈降低趋势,而非光化学淬灭(NPQ)呈先降低后增加的趋势.在土壤施加菌肥剂量0.67和1.00 g·kg^-1处理时,光合机构的过剩光能减少,向光化学反应方向分配的光能增多,光能利用效率提高.在连作土壤中施加适量(0.67～1.00 g·kg^-1)的球毛壳ND35菌肥,能在一定程度上提高杨树的根系生理活性,提高杨树叶片对光能的利用效率,有利于改善杨树叶片的光合机构运转状态,提高叶片的光合作用效率.     

土壤水分对温室春黄瓜苗期生长与生理特性的影响

以津优1号黄瓜为试验材料．研究了土壤不同水分含量对温室春黄瓜苗期生长与生理特性的影响。结果表明,在土壤水分为田间持水量90％时．黄瓜幼苗长势健壮,茎粗大,根系活力强,叶绿素含量和光合速率高．与其它处理差异显著,说明土壤含水量过高或过低均不利于培育黄瓜壮苗。株高和叶面积随土壤含水量的升高而增加;细胞汁液浓度随土壤含水量的升高而降低．且对植株水分状况反应十分敏感,可以用来作为判断植株水分盈亏状况的生理指标。