施氮对半湿润农田冬小麦冠层叶片氮素含量和叶绿素相对值垂直分布的影响

选用半湿润地区土垫旱耕人为土和冬小麦品种‘小偃22’,通过田间试验研究了在不同施氮水平下冬小麦不同生育期冠层叶片含氮量、叶绿素相对值的垂直分布规律,并分析了它们与小麦穗粒重的相关性。结果表明,小麦各生育期冠层叶片含氮量从上至下呈明显递减规律,并且均随施氮量增加含氮量逐渐提高,倒一叶平均比倒二叶高15.83%,倒二叶平均比倒三叶高25.79%;随着施氮量增加,各叶位间叶片含氮量梯度差在拔节期和孕穗期相对稳定,而倒二叶与倒三叶含氮量梯度在成熟期逐渐加大。冠层叶片叶绿素相对值的垂直分布规律与含氮量相似,倒一叶平均比倒二叶高6.5%,倒二叶平均比倒三叶高27.43%。叶片叶绿素相对值与其含氮量呈极显著正相关(r=0.744**,n=234),其间的一元饱和回归方程为ySPAD=87.90xN/(2.29 xN)(R2=0.710);各叶位叶绿素相对值、叶片含氮量均与其穗粒重大多呈显著正相关,并以倒一叶的相关性最密切。研究发现,施氮能提高小麦冠层叶片的含氮量和叶绿素相对值以及它们在叶片间的梯度差,但不能改变它们自上而下逐渐递减的垂直分布规律。     

三种栽培模式下不同基因型冬小麦旗叶衰老代谢比较

为了探索冬小麦在不同栽培模式下功能叶片衰老代谢的生理机制,以cp02(213)、cp99(1)和陕农512为材料,比较研究了常规栽培、覆草栽培、地膜覆盖3种栽培模式下小麦旗叶衰老代谢特性.结果表明,覆草栽培叶面积、旗叶功能期、叶绿素含量、叶片保护酶活性(SOD、POD、CAT)显著高于常规栽培,膜脂过氧化程度较低,叶片衰老速度缓慢,代谢强度旺盛,有利于籽粒灌浆和光合产物的积累.灌浆前期,地膜覆盖叶面积、旗叶功能期、叶绿素含量、叶片保护性酶活性(SOD、POD、CAT)显著高于常规栽培,膜脂过氧化程度低于常规栽培;灌浆后期,叶绿素含量急剧下降,叶片衰老速度加快,膜脂过氧化程度加剧.参试品种(系)中陕农512叶片衰老速度缓慢,保绿性好.     

玉米不同叶位叶片叶绿体超微结构与光合性能的研究

对玉米植株基部（第3叶）,中部（果穗叶）和上部（倒2叶）叶位叶片,进行叶绿体超微结构的观察,并测定了叶绿素含量和光合强度,结果表明,不同叶位叶片叶肉细胞中叶绿体的超微结构,随叶位上升而渐趋复杂化,果穗叶最为显著,向上又趋简单,具体表现为基粒片层的数目随叶位上升而增多基质片层和基质也随之增加,果穗叶最多,向上又趋减少,不同叶位叶片叶绿素含量和光合强度,果穗叶高于其它叶位。     

玉米不同叶位叶片叶绿体超微结构与光合性能的研究

对玉米植株基部（第3叶）,中部（果穗叶）和上部（倒2叶）叶位叶片,进行叶绿体超微结构的观察,并测定了叶绿素含量和光合强度,结果表明,不同叶位叶片叶肉细胞中叶绿体的超微结构,随叶位上升而渐趋复杂化,果穗叶最为显著,向上又趋简单,具体表现为基粒片层的数目随叶位上升而增多基质片层和基质也随之增加,果穗叶最多,向上又趋减少,不同叶位叶片叶绿素含量和光合强度,果穗叶高于其它叶位。     

小麦鞘、叶在籽粒形成与成熟过程中的作用

1.小麦叶片、叶鞘的干重消长呈单峰曲綫变化;同一叶位的叶鞘,干重高峰出現較叶片迟,下降持续时間也較叶片长,“和尚麦”最后二叶鞘能延至籽粒成熟期。 2.剪除鞘叶的試驗証明,剪除的时期愈早,减低粒数、粒重愈多,叶片和叶鞘的叶位愈高,影响也愈大。 3.从叶片、叶鞘衰老时期的早晚、干重的消长变化,以及不同时期进行剪叶剪鞘所引起的籽粒生长变化都証明,同一叶位的叶片与叶鞘对籽粒形成的影响,先是叶片的作用較大,然后才是叶鞘的影响。     

低温诱导春性小麦获增产

中国科学院植物研究所光合室已经研究发现小麦叶片中的叶肉细胞、胞内的叶绿体类囊体膜、膜内各冰冻撕裂面上的功能蛋白颗粒。颗粒上所结合的捕获太阳光能的叶绿素 a/b 色素蛋白复合物的含量,及其相应的光合功能,均随叶位的逐渐上升而愈趋复杂和增高,至旗叶达到顶峰的规律之后,我们进一步采用不同时间40—65天的0—4℃低温诱导各性和春性小麦品种,进行秋播和春播的室内外试验中,发现     

杂交水稻开花结实期间叶片衰老

在杂交水秀开花期间,通过剪却穗部部分枝梗和叶片等处理,形成不同的库源比,叶片衰老的生理生化指标变化和结实率的测定表明,杂交水稻组合的库源矛盾大,叶片衰老快;但谷粒数与旗叶面积比不一定高,降低库源比,能明显减缓杂交水稻叶片中蛋白质,叶绿素含量及倒３,４,５片叶叶绿素含量的平均值和旗叶叶绿素含量的比率的下降和丙二醛含量的升高。     

灌水时期和灌水量对小麦氮代谢相关酶活性和籽粒蛋白质品质的影响

以高产强筋小麦品种'济麦20'为试验材料,在防雨池栽条件下研究了灌水时期和灌水量对小麦氮代谢相关酶活性和籽粒蛋白质品质的影响.结果表明,随灌水时期增多和总灌水量增加,小麦开花后旗叶硝酸还原酶活性和谷氨酰胺合成酶活性显著增高,旗叶蛋白质水解酶内肽酶(EP)、氨肽酶(AP)、羧肽酶(CP)活性降低;小麦籽粒清蛋白和球蛋白含量增加,而籽粒谷蛋白和醇溶蛋白含量、成熟期籽粒谷醇/清球比值(谷蛋白+醇溶蛋白含量/清蛋白+球蛋白含量)降低;面粉沉降值和面团稳定时间显著降低,籽粒产量显著增加.研究发现,在本试验条件下,小麦全生育期灌水3次处理(底墒水+拔节水+开花水)在灌浆前中期旗叶NR和GS活性、灌浆中后期旗叶EP、CP、AP 活性均较高,且成熟期籽粒蛋白质含量、谷醇/清球比值、面团稳定时间、籽粒产量亦较高,是获得小麦高产优质的最佳灌水处理.     

施氮量和栽培模式对旱地冬小麦旗叶衰老及其活性氧代谢的影响

以冬小麦小偃22为试验材料,研究3种栽培模式(常规栽培、覆草栽培、地膜覆盖)和3种施氮水平(施纯氮0、120和240 kg/hm2)下旗叶衰老与活性氧代谢特性.结果表明,与常规栽培(CK)相比较,覆草栽培条件下叶绿素含量始终较高(P<0.05),叶片衰老速度缓慢,代谢强度旺盛,有利于籽粒灌浆和光合产物的积累,产量显著增加(P<0.05).在灌浆前期,地膜覆盖条件下叶片叶绿素含量增加(P<0.05),叶片保护性酶活性(POD、CAT)提高,膜脂过氧化程度低;但在灌浆后期,叶绿素含量急剧下降,叶片衰老速度加快,膜脂过氧化程度加剧,产量仍显著增加(P<0.05).施用氮肥在一定范围内可提高旗叶叶绿素含量和保护性酶活性(POD、CAT),降低膜脂过氧化程度;施氮量为120 kg/hm2时,冬小麦旗叶叶绿素含量最高,叶片衰老迟缓,代谢强度降低缓慢,膜脂过氧化程度低,有利于小麦后期生长和籽粒灌浆,在3种栽培模式下产量均最高.     

糜子不同生育时期不同叶位叶片超微结构研究

对糜子不同生育时期、不同叶位叶片进行电镜观察.结果显示:(1)在籽粒灌浆中期以前,叶肉细胞排列整齐,细胞间隙小,细胞中叶绿体、线粒体等细胞器含量多.叶绿体、线粒体基质含量浓厚,高基粒片层数增加,胞问连丝畅通;(2)在籽粒灌浆中期以后,叶片迅速衰老,细胞解体,细胞间出现间隙,叶绿体减少,叶绿体基粒片层、基质片层解体.嗜锇颗粒变大增多.胞间连丝受到阻碍.(3)不同生育时期不同叶位叶绿体的高基粒片层数差异较大,其中在灌浆中期各叶位叶绿体高基粒片层数最高,在各生育时期旗叶的为最大.     

杂交春性小麦开花结实期间叶片的衰老

用杂交春性小麦901和常规小麦品种陕229为材料,研究了杂交春性小麦901叶片衰老的进程及叶片衰老延迟的原因。研究表明,杂交春性小麦901冠层3叶片叶绿素含量,光合速率,可溶性蛋白质含量在小麦灌浆后期均高于对照常规小麦品种陕229。保护酶SOD活性高且稳定,使活性氧,自由基对细胞膜的伤害减轻,膜结构能较长时间保持健康完整,维持细胞的正常供谢,叶片的功能期延长,同化能力增强。叶片向籽粒和其它器官提供充盈的同化产物,使作物的产量和抗逆性提高。     

K型杂交小麦901及亲本花后茎叶组织结构特征研究

采用大田栽培的杂交小麦901及其父本恢复系R205,母本不育系K3314A和常规小麦陕229(对照)为试材,在花后15～20d内采样,用常规石蜡切片法和显微测量的方法,对旗叶、叶鞘、穗下第一节间及穗轴的维管束结构等进行了系统测定。结果表明,杂交小麦901及其亲本恢复系花后旗叶、鞘、茎节间、穗轴的维管束数目、横截面积均比对照陕229高,输导组织发达,物质运输能力强。这些特征可能是其穗大、小穗数多、颖花较多的结构基础。其同化产物滞留源端可能是其它原因所导致。而不育系的维管束数目少,横截面积小,可能与其不育特性有关。     

Effects of Light intensity on Photosynthetic Characteristics of Wheat Seedling

The contents of pigments and chlorophyll-protein complexes, fluorescence characteristics and electron transport rate were compared for wheat seedlings grown under different light intensities. Leaves of wheat seedlings grown under low-light intensity (2 klx) had lower chlorophyll and carotenoid contents on leaf area or fresh weight basis, a lower ratio of chlorophyll a/b, lower CPIa and CPI contents in photosynthetic membranes than those of wheat seedlings grown under high-light intensity (20 klx). However, the LHCP content in photosynthetic membranes was higher in the former. The kinetic studies of fluorescence induction showed that wheat seedlings grown under low-light intensity possessed a bigger photosynthetic unit, lower PSⅡ activity and lower efficiency of primary energy conversion than those grown under high-light intensity. Moreover. lower electron transport rate was found in the chloroplasts of the former.     

Differential changes in degradation of chlorophyll-protein complexes of photosystem I and photosystem II during flag leaf senescence of rice.

The stability of chlorophyll-protein complexes of photosystem I (PSI) and photosystem II (PSII) was investigated by chlorophyll (Chl) fluorescence spectroscopy, absorption spectra and native green gel separation system during flag leaf senescence of two rice varieties (IIyou 129 and Shanyou 63) grown under outdoor conditions. During leaf senescence, photosynthetic CO(2) assimilation rate, carboxylase activity of Rubisco, chlorophyll and carotenoids contents, and the chlorophyll a/b ratio decreased significantly. The 77 K Chl fluorescence emission spectra of thylakoid membranes from mature leaves had two peaks at around 685 and 735 nm emitting mainly from PSII and PSI, respectively. The total Chl fluorescence yields of PSI and PSII decreased significantly with senescence progressing. However, the decrease in the Chl fluorescence yield of PSI was greater than in the yield of PSII, suggesting that the rate of degradation in chlorophyll-protein complexes of PSI was greater than in chlorophyll-protein complexes of PSII. The fluorescence yields for all chlorophyll-protein complexes decreased significantly with leaf senescence in two rice varieties but the extents of their decrease were significantly different. The greatest decrease in the Chl fluorescence yield was in PSI core, followed by LHCI, CP47, CP43, and LHCII. These results indicate that the rate of degradation for each chlorophyll-protein complex was different and the order for the stability of chlorophyll-protein complexes during leaf senescence was: LHCII>CP43>CP47>LHCI>PSI core, which was partly supported by the green gel electrophoresis of the chlorophyll-protein complexes.     

Functional and structural organization of chlorophyll in the developing photosynthetic membranes of Euglena gracilis Z. V-separation and characterization of pigment-protein complexes of the differentiated thylakoids

Low temperature sodium dodecyl sulfate polyacrylamide gel electrophoresis following mild solubilization of Euglena thylakoid components allowed to resolve, in addition to the main CP1, CPa and LHCP chlorophyll-protein complexes, the additional CP1a and LHCP green bands. A carotenoid enriched band CPc can be separated from CPa using high acrylamide concentration. Pigment and polypeptide composition of these complexes were analyzed by absorption and fluorescence measurements and two dimensional gel electrophoresis. Spectral properties of CP1 and CP1a indicate an heterogenous organization of chlorophyll and the presence of significant amount of chlorophyll b in these complexes. They both contain a major 68 kilodalton polypeptide associated with three minor low molecular weight polypeptides in CP1a. CPa and CPc exhibit a characteristic fluorescence emission at 687 nm and they each contain one polypeptide of 54 and 41 Kda respectively. LHCP and LHCP are less abundant than in higher plant thylakoids and they contain a lower proportion of chl b (chl a: chl b=3). They include two polypeptides of 26 and 29 Kda.Abbreviations chl chlorophyll - SDS Sodium Dodecyl Sulfate - EDTA Ethylene Diamine Tetraacetic Acid - DTT Dithiothreitol     

Characterization of a New Chlorophyll-Protein Complex and Studies on Some Properties of Other Chlorophyll-Containing Bands

1. The chlorophyll-protein complexes of sun plant spinach and shade plants Malaxis monophyllos (L.) Sw. and Chlorophytum comosum (Thunb.) Jacques were resolved by SDS-PAGE at lower temperature (2—4 ℃). Besides 8 chlorophyll-containing bands Ⅰa, Ⅰb, Ⅰc, Ⅱa, Ⅱb, Ⅱc, Ⅲ and Ⅳ mentioned in our previous paper (Chu et al., 1980), three more small chlorophyll-containing bands were also observed. Among these small bands Ⅱa which often appeared between Ⅰc and Ⅱa looked like a oligomer of LHCP complex according to its properties in colour, absorption spectrum and fluorescence emission etc. 2. When electrophoresis was carried out at lower temperature (2—4 ℃), the quantity of free pigments (Ⅲ) was obviously lower, while the relative quantities of LHCP Ⅱa, Ⅱb and PS Ⅱ’s band (Ⅳ) were apparently higher than those carried out at higher temperature (12—15 ℃). At lower temperature three bands of Ⅰ could be resolved in shade plants M. monophyllos and C. comosum, and at higher temperature there was only one band of Ⅰ (Ⅰc). But at higher temperature three bands of Ⅰ could be resolved in sunflower. 3. The percentage of LHCP complexes of shade plant M. monophyllos in total amount of chlorophyll (57%) was obviously higher than that of sun plant spinach (43%). The percentage of complexes Ⅰ of sun plant spinach in amount of total chlorophyll (27%) was obviously higher than that of shade plant M. monophyllos (14%). The relative quantity among three bands of Ⅰ in different Plants is different. 4. The chl a/b ratio of LHCP bands of shade plants were lower than that of corresponding bands of sun plants. The chl a/b ratio of Ⅱa of M. monophyllos was 1.1, Ⅱc, 1.2; but that of Ⅱa of spinach was 1.4, Ⅱc, 1.66.     

The light-harvesting system of Euglena gracilis during the cell cycle

The apoproteins of the light-harvesting chlorophyll-protein complexes LHCI and CP29 (apparent molecular weights of 27 kDa and 29 kDa, respectively) of Euglena gracilis were identified immunologically. Both complexes are present in the thylakoids of autotrophically cultured Euglena cells during the whole cell cycle. The relative amount of each apoprotein tends to increase towards the end of the cell cycle. The light-harvesting chlorophyll-protein complex of photosystem II, LHCII, of E. gracilis contains chlorophyll a, chlorophyll b, neoxanthin, diadinoxanthin and beta-carotene. Its chlorophyll a/b ratio is about 1.7 during the whole cell cycle. About 9 h after cell division the ratio of diadinoxanthin to chlorophyll a is doubled for a time of 3–4 h. The relevance of this increase during one developmental stage is discussed in relation to the insertion and-or assembly of newly synthesized LHCII.Abbreviations LHCP light-harvesting chlorophyll-protein complex - PS photosystem This research was partly supported by the Deutsche Forschungsge meinschaft.     

Contribution of the wheat (Triticum aestivum L.) flag leaf to grain yield in response to plant growth regulators

In West-Europe, intensive cereal management uses plant growth regulators (PGRs) especially for wheat. A green-house experiment compared the effects of two PGRs on flag leaf characteristics and yield of winter wheat. Chlormequat chloride + choline chloride (CCC) and chlormequat chloride + choline chloride + imazaquin (CCC+I) were applied to winter wheat at growth stage 5 (Feekes Large scale). CCC and CCC+I significantly increased flag leaf surface area at anthesis. Both treatments also enhanced chlorophyll content of the main stem flag leaf. The grain filling period was extended with PGR application by 2 days. CCC and CCC+I significantly increased net CO₂ assimilation rates during the flag leaf life. No effects of PGR spraying were observed on the pattern of ¹⁴C labelled assimilate distribution. Increased grain yield was due to the increase in average grain weight. The results indicate that PGR treatments increased flag leaf contribution to grain filling. The addition of imazaquin (I) to chlormequat (CCC) improved the effects of CCC.     

RuBP carboxylase activity in wheat following ear emergence and evaluation of the role of ear

Ribulose bisphosphate carboxylase activity and chlorophyll content were measured in the leaves and reproductive parts of two wheat cultivars after ear emergence. The chlorophyll content of the flag leaf was mostly higher than that of the awns and glumes. Awns had the highest chlorophyll content among reproductive parts. Light transmission to the lower leaves was higher in the dwarf cultivar Moti than in the medium tall cultivar Kalyansona. RuBP carboxylase activity in Kalyansona leaves was higher than in Moti leaves. In postanthesis stages there was no difference in RuBP carboxylase activity in the flag leaf and lower leaves between cultivars. Awns had the maximum activity of RuBP carboxylase followed by glumes and grains among ear parts. The relative capacity for photosynthesis in the ear parts was several times higher than in the flag leaf on a unit chlorophyll basis. It is suggested that in a crop canopy in the field, the spike(ear) may have a greater importance in grain development than has been previously estimated.