Effect of the phenylurea cytokinin 4-PU-30 on the growth and protein composition of maize seedlings

The action of the phenylurea cytokinin 4-PU-30 on maize seedling growth, photosynthetic parameters, and leaf protein composition was investigated. The applied phenylurea cytokinin increased leaf growth and photosynthetic activity of the seedlings. It also elevated chlorophyll and total nitrogen content in leaves, as well as the quantity of individual protein fractions. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) of soluble proteins (albumins plus globulins) revealed four protein polypeptides with molecular masses of 27,000, 24,000, 17,000, and 15,000. Comparison of the polypeptides from treated plants with relevant polypeptides from control plants showed some significant, quantitative differences. New proteins, of similar molecular mass, may be produced in treated plants.     

Effect of Cytokinins on Photosynthetic Pigments and Chlorophyllase Activity in in Vitro Cultures of Axillary Buds of Dianthus caryophyllus L.

The effect of benzyladenine (BA) and two phenylurea cytokinins, N-phenyl-N′-(2-chloro-4-pyridyl)urea (4-PU-30) and thidiazuron (TDZ), on the growth, photosynthetic pigment content, and activity of chlorophyllase (chlorophyll-chlorophylliodhydrolase, EC 3.1.1.14) of in vitro cultures of carnations was studied. All cytokinins caused a rise in the fresh weigth and a drop in the dry weight of leaf mass produced by the explanted buds. Both 4-PU-30 and TDZ increased the chlorophyll content and this correlated with changes in chlorophyllase activity. The effect of 4-PU-30 and TDZ was similar to that caused by BA but at 10-fold or 100-fold lower concentrations. The application of higher concentrations of the phenylurea cytokinins caused an increase in the chlorophyll a/chlorophyll b ratio. However, at equimolar concentrations, the purine and both phenylurea cytokinins had opposite effects, probably indirect and related to some malformations caused by phenylureas. 4-PU-30 increased, but TDZ decreased, photosynthetic membrane stability, which argues for a different molecular organization of the chloroplast membranes. Received February 26, 1996; accepted May 30, 1997     

Structural and functional alterations in radish plants induced by the phenylurea cytokinin 4-PU-30

Single treatment of expanding radish leaves with N₁-(2-chloro-4-pyridyl)-N₂-phenylurea (4-PU-30) lead to the stimulation of root cambial tissue activity and root growth. Leaf thickness, the volume of chlorophyll (Chl) containing cells per unit leaf area, starch content in the chloroplasts, and the Chl content increased simultaneously. These alterations were associated with increased leaf net photosynthetic rate and stomatal conductance in treated plants. This study was supported by the Bulgarian National Foundation for Scientific Researches (Contract B-413). 4-PU-30 was kindily provided by Prof. K. Shudo, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan. We wish also to thank Dr. T. Tsonev for valuable advises.     

降水和温度变化对长白山地区水曲柳幼苗生长和光合参数的影响

以我国温带主要阔叶树种水曲柳幼苗为对象,在长白山自然保护区海拔740 m和1200 m布设两处试验地,分别进行增水30％(+W)、减水30％(-W)和自然降水(CK)处理试验,分析植株生长和叶片光合作用参数、可溶性蛋白和光合色素含量,以及降水和温度变化对水曲柳光合作用的影响.结果表明:温度变化对水曲柳幼苗生长和光合生理指标的影响显著,与海拔1200 m样地相比,海拔740 m样地3个处理水曲柳幼苗的基径、株高、叶片叶绿素含量和可溶性蛋白含量显著增加,胡萝卜素含量降低;叶片净光合速率、气孔导度、蒸腾速率和气孔限制值均显著升高,而胞间CO2浓度和叶片水分利用效率显著降低.水曲柳幼苗光合能力的下降归因于非气孔因素限制.降水变化对水曲柳幼苗生长及光合作用的影响均不显著.     

LED光质对番茄幼苗生长及内源性GA和IAA含量的影响

采用发光二极管调制光谱能量分布,以荧光灯为对照,研究不同光质(红光、蓝光、黄光、绿光)下番茄幼苗生理特性及内源性GA和IAA水平与其生长的关系。结果表明:(1)红光和蓝光有利于番茄幼苗茎的伸长和叶面积的增加。(2)除蓝光处理下可溶性糖含量和SOD活性与对照无显著性差异外,各单色光质处理下番茄幼苗根系活力、色素含量、可溶性蛋白和可溶性糖含量、SOD活性较对照均显著降低。(3)与对照相比,各单色光质处理下番茄幼苗叶片中GA含量显著降低,IAA含量在红光下显著升高,在黄光和绿光下显著降低,且叶面积与IAA含量呈显著正相关关系。(4)番茄幼苗茎中GA和IAA含量在红光和蓝光处理下显著高于对照和黄、绿光处理,且株高与茎中GA和IAA含量呈正相关关系。     

叶面配施镁锌钼对银杏苗叶生长和药用品质的影响

以两年生银杏苗为研究对象,采用室内模拟与盆栽试验相结合的方法,研究了叶面配施低、中、高浓度的镁、锌、钼对银杏叶产量和药用成分含量及其产量的影响,以明确叶用银杏叶面微肥中镁锌钼的适宜浓度。结果显示:(1)镁锌钼配施能提高单叶面积、叶片厚度、单株叶面积和叶生物量,并以配施组合Mo3(2%Mg+0.3%Zn+0.1%Mo)对叶生物量的提高幅度较大(64.9%)。(2)中锌中钼配施镁肥对银杏叶绿素、可溶性糖和可溶性蛋白质含量的正效应随着镁肥喷施浓度的增加而降低,中镁中钼配施锌肥、中镁中锌配施中钼对叶片叶绿素、可溶性糖含量的正效应随着配施肥料浓度的升高而降低,而可溶性蛋白含量与配施肥料浓度呈正相关。(3)镁锌钼配施能提高叶片总黄酮、萜内酯含量,以及单株总黄酮和萜内酯产量,以配施组合Mo3对单株总黄酮、萜内酯产量的提高幅度最大,分别为2.96倍和1.70倍。(4)配施高浓度的肥料(Mg4、Zn4和Mo4)不同程度地降低了镁锌钼配施对部分指标的正效应。研究表明,配施适当浓度的镁锌钼叶面肥可在一定程度促进银杏苗叶绿素合成,上调可溶性糖和可溶性蛋白质等初生代谢物质积累,改善其叶片生长和药用品质,提高叶产量及药用品质构成要素;微肥2%Mg+0.3%Zn+0.1%Mo是本试验条件下提高银杏叶产量、药用成分含量和产量较为理想的叶肥组合。     

增铵营养对小麦光合作用及硝酸还原酶和谷氨酰胺合成酶的影响

采用水培试验研究不同形态氮营养(NH4^+／NO3^-分别为0／100、50／50和100／0)对小麦光合作用及氮代谢关键酶活性的影响．结果表明,增铵营养较单—NO₃^-营养显著提高叶片叶绿素含量、净光合速率及可溶性糖含量,叶、根中可溶性蛋白质含量和叶片硝酸还原酶活性。而对谷铵酰胺合成酶活性影响较小．与单—NO₃^-营养相比。增氨营养下叶片较高的可溶性糖含量与净光合速率的提高相关。而维持较高的叶片和根系可溶性糖／可溶性蛋白质比例有利于氮同化和生长．因此,增铵营养下提高了叶片净光合速率、可溶性糖含量和硝酸还原酶活性。维持较高叶片和根系可溶性糖／蛋白质比例。从而促进小麦生长．     

Influence of Auxin and Gibberellin on in Vivo Protein Synthesis during Early Pea Fruit Growth

Developing pea fruits (Pisum sativum L.) offer a unique opportunity to study growth and development in a tissue that is responsive to both gibberellins (GAs) and auxin (4-chloroindole-3-acetic acid[4-CI-IAA]). To begin a molecular analysis of the interaction of GAs and auxins in pea fruit development, in vivo labeling with [35S]methionine coupled with two-dimensional gel electrophoresis were used to characterize de novo synthesis of proteins during gibberellic acid (GA3)-, 4-CI-indoleacetic acid-, and seed-induced pea pericarp growth. The most significant and reproducible polypeptide changes were observed between molecular weights of 20 and 60. Comparing about 250 de novo synthesized proteins revealed that seed removal changed the pattern substantially. We identified one class of polypeptides that was uniquely seed induced and five classes that were affected by hormone treatment. The latter included 4-CI-IAA-induced, GA3-induced, GA3- and 4-CI-IAA-induced, 4-CI-IAA-repressed, and GA3- and 4-CI-IAA-repressed polypeptides. Similar patterns of protein expression were associated with both hormone treatments; however, changes unique to GA3 or 4-CI-IAA treatment also indicate that the effects of GA3 and 4-CI-IAA on this process are not equivalent. In general, application of 4-CI-IAA plus GA3 replaced the seed effects on pericarp protein synthesis, supporting our hypothesis that both hormones are involved in pea pericarp development.     

Relation between relative growth rate, endogenous gibberellins, and the response to applied gibberellic acid for Plantago major

Relationships between relative growth rate (RGR), endogenous gibberellin (GA) concentration and the response to application of gibberellic acid (GA₃) were studied for two inbred lines of Plantago major L., which differed in RGR. A4, the fast-growing inbred line, had a higher free GA concentration than the slow-growing W9, as analyzed by enzyme immunoassay. GA₃ application increased total plant weight and RGR₃ particularly for the slow-growing line. Chlorophyll a content and photosynthetic activity per unit leaf area were decreased, while transpiration rate was unaffected by GA₃ application. The increase in RGR by GA₃ application was associated with an increased leaf weight ratio; specific leaf area and percentage of dry matter in the leaves were only temporarily affected. Root respiration rate per unit dry weight was unaffected.
The correlation between low RGR, low GA concentration and high responsiveness to applied GA₃ supports the contention that gibberellins are involved in the regulation of RGR. However, the transient influence of GA₃ application on some growth components suggests the involvement of other regulatory factors in addition to GA.     

Light-dependent regulation of the synthesis of soluble and intracytoplasmic membrane proteins of Rhodopseudomonas sphaeroides.

Cells of Rhodopseudomonas sphaeroides grown under saturating light conditions (30 W/m2) and then shifted to low light intensity (3 W/m2) required 2.5 h to adapt to the new lower light conditions. After the shift, cell growth, whole cell protein accumulation, and bacteriochlorophyll accumulation ceased immediately. Approximately midway into the adaptation period, bacteriochlorophyll synthesis commenced at a new, higher rate, which continued through the beginning of the low-light growth period until new steady-state levels were reached. Immediately after the downshift, the rate of cellular protein synthesis declined to 22% of its preshift rate. Pulse-labeling of protein throughout the adaptation period and comparison with a steady-state prelabel culture revealed that synthesis of two of the three light-harvesting proteins, as well as two additional high-molecular-weight photosynthetic membrane proteins, was derepressed three- to fivefold compared with bulk cellular protein. Finally, the synthesis of at least three soluble proteins showed light-dependent regulation after the light downshift. These results are discussed in terms of the light-dependent regulation of synthesis of the photosynthetic membrane macromolecular components and the division of protein synthesis between the photosynthetic membranes and the soluble cell phase.     

Activity and quantity of ribulose bisphosphate carboxylase-and phosphoenolpyruvate carboxylase-protein in two Crassulacean acid metabolism plants in relation to leaf age,nitrogen nutrition,and point in time during a day/night cycle

Activity of ribulose 1,5-bisphosphate (RuBP) carboxylase in leaf extracts of the constitutive Crassulacean acid metabolism (CAM) plant Kalanchoe pinnata (Lam.) Pers. decreased with increasing leaf age, whereas the activity of phosphoenolpyruvate (PEP) carboxylase increased. Changes in enzyme activities were associated with changes in the amount of enzyme proteins as determined by immunochemical analysis, sucrose density gradient centrifugation, and SDS gel electrophoresis of leaf extracts. Young developing leaves of plants which received high amounts of NO ₃ ^- during growth contained about 30% of the total soluble protein in the form of RuBP carboxylase; this value declined to about 17% in mature leaves. The level of PEP carboxylase in young leaves of plants at high NO ₃ ^- was an estimated 1% of the total soluble protein and increased to approximately 10% in mature leaves, which showed maximum capacity for dark CO₂ fixation. The growth of plants at low levels of NO ₃ ^- decreased the content of soluble protein per unit leaf area as well as the extractable activity and the percentage contribution of both RUBP carboxylase and PEP carboxylase to total soluble leaf protein. There was no definite change in the ratio of RuBP carboxylase to PEP carboxylase activity with a varying supply of NO ₃ ^- during growth. It has been suggested (e.g., Planta 144, 143–151, 1978) that a rhythmic pattern of synthesis and degradation of PEP carboxylase protein is involved in the regulation of -carboxylation during a day/night cycle in CAM. No such changes in the quantity of PEP carboxylase protein were observed in the leaves of Kalanchoe pinnata (Lam.) Pers. or in the leaves of the inducible CAM plant Mesembryanthemum crystallinum L.Abbreviations CAM Crassulacean acid metabolism - RuBP ribulose 1,5-bisphosphate - PEP phosphoenolpyruvate - G-6-P glucose-6-phosphate     

Physiological Responses of Pea Plants to Salinity and Gibberellic Acid

Pea is a seed legume. It is rich in cellulose fibre and protein. It is also a significant source of minerals and vitamins. In this paper, we set out to better characterize the physiological responses of Pisum sativum L. to the combined effects of NaCl, 100 mM and gibberellins (GA3). Our analysis revealed that NaCl caused a decrease in growth resulting in a reduction in root elongation, distribution and density, leaf number and leaf area, and a decrease in dry matter of roots and shoots. However, the contribution of GA3 in the salty environment induced an increase in these different parameters suggesting an improving effect of this hormone on growth of pea in presence of salt. NaCl also led to a disturbance of the photosynthetic machinery. Indeed, level of chlorophyll pigments (a and total) and photosynthetic activity were decreased compared to the control plants. However, the exogenous supply of GA3 restored this decrease in net CO₂ assimilation, but not in chlorophyll content. Additional analyses were performed on the effect of salinity/GA3 interaction on osmolytes (soluble sugars and starch). Our results showed an increase in sugars and a decrease in starch in the presence of 100 mM NaCl. The salt-GA3 combination resulted in compensation of soluble sugar contents but not of starch contents, suggesting a beneficial effect of GA3 under saline stress conditions. Level of three main polyamines putrescine, spermidine, and spermine increased significantly in all organs of salt-treated plants.     

有色膜遮光对烤烟生长和光合特性及其初烤品质的影响

以自然光为对照,采用红色、白色、蓝色、黄色4种有色薄膜于2010~2011年从团棵期开始对大田烤烟进行遮光处理,研究不同光质对烤烟生长、光合特性及初烤品质指标的影响。结果显示:(1)红膜处理最大叶长宽比最小、叶面积最大,黄膜处理则相反。(2)红、蓝膜处理烟叶净光合速率、气孔导度、蒸腾速率明显高于自然光处理,白、黄膜处理略高于对照或与对照持平,且遮膜处理前期红膜高于蓝膜处理,后期蓝膜高于红膜处理。(3)红、蓝膜处理有利于提高倒5叶SPAD值,黄膜处理则相反。(4)红膜处理显著降低了中部叶蛋白质、总氮含量和氮碱比,提高了施木克值,并显著提高了上部叶可溶性糖含量和氮碱比,降低了施木克值;蓝膜处理显著提高了中部叶烟碱和多酚含量,降低了可溶性糖含量、施木克值及氮碱比,并显著提高了上部叶蛋白质、总氮、烟碱和多酚含量,降低了施木克值,提高了氮碱比;黄膜处理显著降低了中上部叶蛋白质、总氮、烟碱和多酚含量,提高了上部叶施木克值、降低了氮碱比。研究表明,红、蓝膜处理更利于烟叶发育和光合特性的提高,初烤烟叶化学成分更协调,利于优质烟叶的形成。     

Photosystems activities and polypeptide composition of Cyamopsis tetragonoloba and Vigna mungo thylakoids as affected by exclusion of solar UV radiation

The impacts of solar UV (280–400 nm) radiation on photosynthetic activities and polypeptide composition of thylakoids of cluster bean (Cyamopsis tetragonoloba L, UV-B sensitive) and black gram (Vigna mungo L., UV-B resistant) plants were compared. The activity of photosystem 1 and especially photosystem 2 increased in cluster bean while decreased in black gram, when either UV-B or UV-B + UV-A radiation was removed as compared to control plants. Exclusion of UV-B radiation caused changes in the protein composition of the thylakoids particularly in the 33, 23 and 17 kDa proteins of photosystem 2.     

Effects of elevated CO<Subscript>2</Subscript> and nitrogen on wheat growth and photosynthesis

The effects of nitrogen [75 and 150 kg (N) ha⁻¹] and elevated CO₂ on growth, photosynthetic rate, contents of soluble leaf proteins and activities of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and nitrate reductase (NR) were studied on wheat (Triticum aestivum L. cv. HD-2285) grown in open top chambers under either ambient (AC) or elevated (EC) CO₂ concentration (350 ± 50, 600 ± 50 μmol mol⁻¹) and analyzed at 40, 60 and 90 d after sowing. Plants grown under EC showed greater photosynthetic rate and were taller and attained greater leaf area along with higher total plant dry mass at all growth stages than those grown under AC. Total soluble and Rubisco protein contents decreased under EC but the activation of Rubisco was higher at EC with higher N supply. Nitrogen increased the NR activity whereas EC reduced it. Thus, EC causes increased growth and P_N ability per unit uptake of N in wheat plants, even if N is limiting.