谷胱甘肽提高月季切花失水胁迫耐性与GR活性的关系

 本研究确定了切花月季‘Samantha’预处理采用的谷胱甘肽(GSH) 及其生物合成抑制剂丁胱亚磺酰胺〔L-buthione (S, R) sulfoximine, BSO〕适宜浓度, 探讨了GSH和BSO预处理对花朵水势、花瓣中MDA含量、GSH含量以及GR活性等的影响。结果表明: 与失水胁迫对照处理相比较, 2 mmol/L GSH预处理明显提高了月季切花瓶插期间花朵水势, 显著降低了花瓣中MDA含量, 有效提高了花瓣中GSH含量和GR活性。2 mmol/L BSO预处理获得了理想的反证结果。结果说明, GSH对切花月季‘Samantha’失水胁迫耐性的改善与花瓣中GR活性的提高相联系。     

Changes in parameters of cell senescence in carnation flowers after cold storage

The effects of cold storage on vase life, ethylene (C₂H₄) production, and parameters of cell senescence, were measured in flowers of spray carnation (Dianthus caryophyllus L.), cultivar ‘Pink Royalette’. Storage for 6 or 12 days at 2°C led to a reduction in the subsequent vase life at 20°C. In addition, storage caused a reduction in the time between the rise in ethylene production and the end of vase life. That is, cold storage increased the sensitivity of the petal cells to endogenous C₂H₄.Normal aging of flowers for 6 days at 20°C led to decreased capacity of petals to take up [¹⁴C] sucrose, decreased activity of membrane ATPase, increased membrane microviscosity and decreased membrane phospholipid content, relative to the levels in fresh flowers. However, cold storage of flowers for 6 days at 2°C caused opposite changes in the levels of these senescence parameters (measured at constant temperature). It was concluded that cold storage does not simply lead to a slow rate of senescence, but has other effects on cell properties.     

Water relations and keeping-quality of cut Gerbera flowers. II. Water balance of ageing flowers

Time course of fresh weight (F.W.), water content as percentage of dry weight of petals (W.C.), maximal water content after saturation of petals (W.C._max), relative water content of petals (R.W.C.), absorption rate (abs.), transpiration rate, water potential of petals (ψ), stem flow resistance (R_stem) and flower developmental stage of cut Gerbera flowers in solutions with chemicals were determined. In a solution with silver nitrate, an increase of R_stem was evident after 4 days, resulting in a decrease of abs., F.W., W.C., R.W.C. and ψ. A constant pH of the vase water of 3.5 could prevent this increase in R_stem. The pH of the vase water was influenced by the flower itself.When the increase of R_stem was prevented, the absorption rate was higher than the transpiration rate during the first 5 days after cutting, which resulted in an increase of F.W., W.C. and R.W.C. After day 5, absorption was lower than transpiration, the F.W., W.C., W.C._max and R.W.C. decreased, while ψ remained steady. It is suggested that the water deficit-water potential relationships of the petals change with age, resulting in a lower water-holding capacity of the petals.     

稀土元素铈对‘红地球’葡萄组培苗生长的影响

 以‘红地球’葡萄组培苗茎段为外植体，在培养基中添加1～100 mg·L^-1 Ce(NO₃)₃，，研究 不同浓度Ce(NO₃)₃对其生长的影响。结果表明适宜浓度的Ce(NO，)，(1～10 mg·L^-1 )对‘红地球’葡萄组培苗的生长具有促进作用，加快外植体生根，侧根数及侧根总长显著增加,根、茎、叶鲜样质量和干样质量也增加，根系活力提高而增加移栽成活率，增加叶绿素含量，有利于植株对矿质营养的吸收。而100 mg·L^-1。Ce(NO₃)₃对葡萄组培苗生长起明显抑制作用。     

Changes in oxidative damage, antioxidant enzyme activities and polyamine contents in leaves of grafted and non-grafted eggplant seedlings under stress by excess of calcium nitrate

The effect of 80 mmol L⁻¹ stress by excess of calcium nitrate [Ca(NO₃)₂] on biomass production, oxidative damage, antioxidant enzymes activities and polyamine contents in leaves of grafted and non-grafted eggplant (Solanum melongena L.) seedlings were studied, in which grafted plants were grafted on a salinity tolerant rootstock (Solanum torvum Swartz). The results showed that on the 15th day of treatment, the biomass production reduction of non-grafted seedlings was significantly higher than that of grafted seedlings. Under stress by excess of Ca(NO₃)₂, superoxide anion radical (O₂⁻) producing rate, electrolyte leakage percentage, contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) of non-grafted seedlings were significantly higher than those of grafted seedlings, but activities of superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) of grafted seedlings were significantly higher than those of non-grafted seedlings, moreover, contents of free, soluble conjugated and insoluble bound polyamines of grafted seedlings were significantly higher than those of non-grafted seedlings, and activities of diamine oxidase (DAO, EC 1.4.3.6) and polyamine oxidase (PAO, EC 1.5.3.3) of grafted seedlings were significantly lower than those of non-grafted seedlings. The possible roles of antioxidant enzymes and polyamines in protective mechanism of grafted eggplant seedlings to stress by excess of Ca(NO₃)₂ were discussed.     

小苍兰切花瓶插生理研究

 以小苍兰品种‘上农金皇后’为材料,观察其鲜切花瓶插过程中花的发育变化及生理特性。结果表明,小苍兰切花单花的瓶插寿命不足一周,整个花序可达10 d。花瓣中的含水量和可溶性蛋白含量在瓶插前期升高,后期则加速下降。超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性呈现相似的变化趋势,在瓶插前期均呈上升趋势,4 d达到峰值后稳步下降;过氧化物酶（POD）活性则在整个瓶插期间持续上升。超氧阴离子自由基（）随瓶插时间增加而不断积累。丙二醛（MDA）含量和相对电导率（EL）也随瓶插时间增加而上升。失水、抗氧化酶活性下降、自由基的累积以及膜脂过氧化水平的增加是小苍兰切花衰老的主要原因。     

Improving the postharvest performance of cut spray ‘Prince’ carnations by vase treatments with nano-silver and sucrose

The postharvest performance of cut spray-type carnations (Dianthus caryophyllus L.) is often limited by the opening, longevity, and coloration of individual florets, and is apparently related to water stress and sugar deficiency. In this study, we found that, compared with deionised water-treated controls, the vase life of cut spray ‘Prince’ carnations was extended by 2.1–4.6 days when held in vase solutions containing1–5 mg L^–1 nano-silver (NS). Moreover, combination treatments with 5 mg L^–1 NS and 2%, 3%, or 4% sucrose consistently further prolonged the vase life, prominently promoted floret opening, and increased the bright pink coloration of petals, thereby markedly enhancing quality performance. Overall, the 5 mg L^–1 NS plus 3% sucrose treatment provided the longest vase life extension (6.6 days) compared with the control, and significantly increased the anthocyanin content in floret petals. Besides, we also showed that the treatment with 5 mg L^–1 NS alone or 5 mg L^–1 NS plus 3% sucrose significantly enhanced their vase solution uptake and relative fresh weight. Further, scanning electron microscopy observations revealed that the NS vase treatments evidently alleviated vascular occlusion by inhibiting bacterial colonisation and biofilm formation on their stem-end cut surfaces and in the xylem vessels.     

抗坏血酸提高月季切花失水胁迫耐性与增加APX活性的关系

 以‘Samantha’品种为试材, 确定了适宜的抗坏血酸(AsA) 预处理浓度, 探讨了AsA和抗坏血酸过氧化物酶(APX) 抑制剂(对氨基酚, β-aminophenol) 预处理对花瓣中相对电导率、AsA含量以及APX活性的影响。与未经失水胁迫的切花月季相比较, 失水胁迫处理抑制切花的开放进程, 缩短了瓶插寿命。AsA 1 000 mg·L ^{- 1}预处理可有效地改善花朵的开放状况, 显著降低花瓣中相对电导率的增加, 明显提高花瓣中AsA的含量和APX活性。500 mg·L ^{- 1} β-aminophenol预处理则起到相反的效应。结果说明,AsA对‘Samantha’月季切花失水胁迫耐性的改善与花瓣中APX活性的提高相联系。     

Water relations and keeping-quality of cut gerbera flowers. IV. Internal water relations of ageing petal-tissue

The relationship between relative water content (R.W.C.) and water potential (ψ_total) of Gerbera petals was studied when cut inflorescences aged in a vase. The regression of sap osmotic potential (ψ_osm), matric potential (ψ_m) and pressure potential (ψ_press) on R.W.C. appeared to be the same for young and old inflorescences.Computing ψ_press as the difference between ψ_total measured with a pressure chamber and ψ_osm + ψ_m gave erroneous results for old cut inflorescences because of the increasing leakage of ions from petal cells. As there existed a correlation between ψ_press and the bending of petals (B) caused by a small weight, it was possible to obtain time courses of ψ_press by measuring B.Time courses of ψ_osm and ψ_press of petals were completely different when inflorescences aged on the plant as compared to ageing in a vase. For inflorescences ageing in a vase without stem plugging, ψ_osm increased during the first 6 days, followed by a decrease, and ψ_press decreased during the entire vase period. When inflorescences were left on the plant, ψ_osm was steady during the first 6 days and increased thereafter, whereas ψ_press was steady until day 6 and then decreased. A hypothesis to explain the difference between inflorescences in the vase and on the plant is given.     

金桂及其芽变花色表型及色素成分分析

以金桂及其芽变花为试验材料,利用英国皇家园艺学会比色卡(Royal Horticultural Society Color Chart,R.H.S.C.C.)和色差仪测量两种花的颜色表型,通过显色法和紫外—分光光度计初步确定了两种花的主要色素类型,并且利用高效液相色谱—光电二极管阵列(HPLC–DAD)测定花瓣中类胡萝卜素和总黄酮含量,利用高效液相色谱—大气压化学电离源—质谱联用技术(HPLC–APCI–MS)和标准品鉴定主要类胡萝卜素成分。结果发现,芽变枝条上的花色由母本的黄色(R.H.S.C.C.12B~13A)变为橙红色,且花瓣边缘和内部颜色不同(内侧R.H.S.C.C.23B,花瓣外缘R.H.S.C.C.N25A);两种花瓣中均含黄酮类化合物,不含花青素苷,且两者的类胡萝卜素含量存在一定差异;从两种花瓣中分离鉴定出主要的类胡萝卜素成分为α–胡萝卜素和β–胡萝卜素,这两种组分和类胡萝卜素总量在芽变花瓣中极显著高于母本,而两种花瓣的总黄酮含量无显著性差异。因此,最终可以确定引起芽变花色变化的主要色素成分为类胡萝卜素。     

Flower colours and pigments in hybrid tuberose (Polianthes)

The flower pigment constitutions of nine hybrids with pink, reddish purple, purple, orange and yellow flowers obtained from the crossings and back-crossings using Polianthes tuberosa ‘Single’ and ‘Double’ and Polianthes howardii were analysed. Among the parents and hybrids, two white flowered cultivars of P. tuberosa had neither carotenoids nor anthocyanins, one hybrid had only carotenoids, four hybrids had only anthocyanins and an additional other four hybrids along with P. howardii had both carotenoids and anthocyanins in their petals. The main anthocyanidin in the petals of anthocyanin containing flowers is cyanidin with which some hybrids also contained delphinidin. Inducing of the anthocyanins and carotenoids from P. howardii into P. tuberosa can contribute to the extension of the diversity of flower colours in further tuberose breeding.     

Experiments on the Storage of Pears in Artificial Atmospheres.

Summary

Cut scapes of the four gerbera cvs Campitano, Dino, Sangria and Testarossa were preharvest sprayed and postharvest dipped or injected with 0 (control), 0.5, 1.0, and 1.5% CaCl₂. Vase life and bending incidence were determined during storage at 258C. Scape calcium content was determined at the end of vase life. Significant extension of vase life and decrease in bending incidence was observed in blooms of `Campitano', `Dino' and `Testarossa' gerberas injected with 1.0% CaCl<sub>2</sub>, followed by dipping in 1.0% CaCl<sub>2</sub> postharvest compared with the control. `Sangria' gerbera scapes preharvest sprayed with 1.0–1.5% CaCl₂ had the longest flower longevity and the lowest bending incidence. Scape calcium concentration of `Campitano', `Sangria' and `Testarossa' increased by 250, 130 and 370%, respectively, compared with the control; calcium treatments resulted in a 3–4 d increase in vase life and a 3-5 d delay in bending incidence relative to the control; treatments with 1.5% CaCl₂ considerably increased scape calcium content but did not contribute any additional increase in the vase life of the flowers. Although postharvest dipping with 1.0% CaCl₂ had moderate results compared with the other treatments it can be considered as a promising postharvest treatment to extend vase life of cut gerberas due to the ease of application.     

Exogenous paraquat changes antioxidant enzyme activities and lipid peroxidation in drought-stressed cucumber leaves

In order to examine whether paraquat modifies the functioning of antioxidants and oxidative stress levels in drought-stressed plants, a cucumber cultivar (Cucumis sativus cv. Yuexiu no. 3) was grown hydroponically for 2 days. Drought stress, which was induced by polyethylene glycol (PEG), increased the contents of malonaldehyde (MDA), superoxide radical (O₂⁻) and hydrogen peroxide (H₂O₂) in cucumber leaves, while pretreatment of paraquat decreased them. Under drought stress induced by PEG, we observed the decreased contents of MDA, H₂O₂ and O₂⁻ in paraquat-pretreated plants in comparison to unpretreated stressed plants. Drought stress and paraquat both increased the activities of antioxidants such as superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), guaiacol peroxidase (GPX, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reducatase (MDHAR, EC 1.6.5.4), glutathione reductase (GR, EC 1.6.4.2), reduced glutathione (GSH) and reduced ascorbate (AsA). But the combined effect of paraquat application and drought stress resulted in the highest activities of antioxidants. So paraquat is able to moderate the activities of scavenging system enzymes and to influence oxidative stress intensity under drought stress induced by PEG.     

Copper distribution and ionic form effects for postharvest treatments of cut Acacia holosericea stems

A short postharvest life is the major constraint associated with cut Acacia flowers and foliage. Treatment with CuSO₄ (Cu²⁺) has previously been shown to improve the longevity of cut Acacia holosericea stems. Towards refining the treatments, a range of Cu²⁺ and Cu⁺ salts were assessed for relative efficacy in improving vase life and water relations of A. holosericea. Five hour pulses with the Cu²⁺ salts CuSO₄, CuCl₂, (CH₃COO)₂Cu and Cu(NO₃)₂ at 2.2 mM gave equally longer vase lives by ∼2.5-fold over deionised water (DIW) and standard tap water (STW) controls. The same Cu²⁺ salts at 0.5 mM in the vase solution also gave significantly (P < 0.05) improved vase life, relative fresh weight and water uptake compared to the DIW control. For Cu²⁺ versus Cu⁺, optimum concentrations with Cu²⁺ could not be directly compared due to the low solubility of the Cu⁺ salt CuCl. However, Cu⁺ from CuCl at 0.415 mM also had positive effects on vase life compared to the DIW control. Thus, both Cu²⁺ and Cu⁺ treatments can enhance vase life parameters for cut A. holosericea foliage. The benefits were irrespective of the counter ion and, thus, Cu²⁺ and Cu⁺per se were responsible. The most effective Cu²⁺ pulse treatment decreased stomatal conductance of phyllodes initially, but did not cause sustained stomatal closure. Cu accumulated to greater levels in basal stem and phyllode tissues than in upper stem and phyllode tissues of cut A. holosericea stems. Possible mechanisms of Cu²⁺/Cu⁺ action are discussed.     

Longevity of Epidendrum ibaguense flowers as affected by pre-loading treatments and vase solution

Summary

Post-harvest longevity of Epidendrum ibaguense cut flowers was maximum when treated for 6 h with 1 g m^–3 Ethylbloc^® [0.14% 1-methylcyclopropene; 1-MCP] followed, or not, by pulsing with 200 g l^–1 sucrose for 12 h. This extended the vase-life from 5.5 d to at least 11 d. Cut inflorescences pulsed with 2.0 mM silver thiosulphate (STS) had reduced abscission of flowers, similar to the effect of 1-MCP. When inflorescences were pulsed with 200 g l^–1 sucrose alone for 12 h, no effect was observed on the vase-life of the flowers. Flowers kept in a vase solution containing 20 g l^–1 sucrose, 150 mg l^–1 citric acid, and 200 mg l^–1 8-hydroxyquinoline citrate did not influence the longevity of 1-MCP or STS pre-treated flowers, but the vase solution had a small influence on retarding abscission compared with flowers kept in distilled water. Adding 0.2 mM STS to the vase solution improved vase-life 1.74- and 1.45-fold compared with the longevity of flowers kept in distilled water or in vase solution alone, respectively. The presence of 0.3 mM AgNO₃ alone, or mixed into the vase solution, had no affect on the vase-life of the flowers.     

Changes in pigments and plastid ultrastructure during ripening of green-fleshed and yellow-fleshed kiwifruit

Fruit of Actinidia deliciosa have green flesh when ripe, whereas fruit of Actinidia chinensis often have yellow flesh when ripe. The outer and inner pericarps of A. deliciosa fruit retain their chlorophyll during ripening. In those fruit of A. chinensis that become yellow on ripening, the colour change is caused by the disappearance of chlorophylls unmasking the yellow carotenoids already present, rather than by increased synthesis of carotenoids. In fruit of A. deliciosa and those fruit of A. chinensis that remain green, the chloroplasts retain their typical morphology during ripening, whereas in fruit of A. chinensis that become yellow during ripening the chloroplasts of the immature green fruit are transformed into fully developed chromoplasts.     

First defense mechanisms of ornamental species suitable for urban green spaces in China exposed to ozone

High concentrations of tropospheric ozone (O₃) represent a serious problem in the Northern Hemisphere, especially in hot spots as urban areas of China. In this study, the first defense mechanisms (i.e., stomatal behavior and morphology, ascorbate regulations) of three widely-used ornamental plant species (Cotinus coggygria Scop., Rosa chinensis Jacq., Tagetes erecta L.) to O₃ were evaluated to test the suitability of these species for utilization in urban green spaces (UGS). Seedlings were exposed to (i) ambient air (AA), (ii) AA + 60 ppb O₃ (AA + 60), and (iii) AA + 120 ppb O₃ (AA + 120) for 60 (C. coggygria and R. chinensis) or 32 days (T. erecta), 9 h d⁻¹. Considering the different physiological responses and O₃ sensitivity among the species, data of the present study reveal that: (i) O₃-induced stomatal closure observed in the three species was not an avoidance-strategy given the lack of a significant relation between g_s and O₃ fluxes into the leaves, a feature that confirm the strong negative effects of O₃ on the photosynthetic metabolism previously reported; and (ii) stomatal morphology, as well as ascorbate regulations, seem to play a pivotal role in the responses of the investigated species to O₃”. Overall, our study highlights the importance of investigating the first defense mechanisms adopted by plants to cope with urban environmental stresses, in order to direct a correct management of UGS.     

红掌切花瓶插期衰老生理的初步研究

对红掌切花在瓶插衰老过程中的水分平衡值、鲜重、可溶性蛋白含量以及过氧化物酶(POD)活性、丙二醛(MDA)含量的变化进行了研究。结果表明:红掌切花在瓶插过程中,水分平衡值由正值变为负值;鲜重和可溶性蛋白含量、过氧化物酶(POD)活性的变化呈先上升后下降的趋势;丙二醛(MDA)含量在瓶插过程中一直呈上升趋势。     

Water relations and keeping-quality of cut Gerbera flowers. V. Role of endogenous cytokinins

The objective of the present work was to investigate if differences in internal water relations, due to differences in membrane permeability, between Gerbera petals of inflorescences ageing in a vase and on the plant could be ascribed to differences in cytokinin activities. Moreover, cytokinin activities in petal-extracts of 3 cultivars, differing in their keeping-quality, were compared.Cytokinin activities (“free” and “bound”) in petals decreased during the first 6 days of the experiment (both in the vase and on the plant). On Day 8, a very high activity was found in almost all the R_f-fractions of the chromatogram. After Day 8, the activity decreased again. For young inflorescences, developing on the plant, a peak level was reached for “free” cytokinins at a very early bud stage and for “bound” cytokinins when the petals were just fully expanded. There were no correlations between petal-cytokinin activities at day of harvest of 3 Gerbera cultivars and their keeping-quality.It is concluded that changes in membrane permeability, which occur during ageing of petals of cut Gerbera inflorescences, are not triggered by changes in cytokinin activities.