外源钾水平对长春花生长和生物碱积累的影响

钾营养对于植物的生长发育具有重要作用,通过对长春花施以不同水平的外源钾,以探讨在不同浓度的钾素营养条件下,长春花生物量和生物碱的积累特点。结果表明,外源钾素营养水平的增加显著促进长春花的株高、根长、生物量积累,其中以10和15 mmol·L^-1浓度下的作用效果最显著。同时,外源的钾素营养水平提高还显著增加长春花的吲哚类生物碱含量,其中长春质碱的含量随着钾素营养浓度增大而增加;文多灵和长春碱随着钾素营养浓度增大都是先增加后减小,在15 mmol·L^-1浓度下达到最大值,过高的钾素营养不利于两者的合成。     

Variations of vinblastine accumulation and redox state affected by exogenous H<Subscript>2</Subscript>O<Subscript>2</Subscript> in <Emphasis Type="Italic">Catharanthus roseus</Emphasis> (L.) G. Don

Effects of exogenous H₂O₂ application on vinblastine (VBL) and its precursors, vindoline (VIN), catharanthine (CAT) and α-3′,4′-anhydrovinblastine (AVBL), were measured in Catharanthus roseus seedlings in order to explore possible correlation of VBL formation with oxidative stress. VBL accumulation has previously been shown to be regulated by an in vitro H₂O₂-dependent peroxidase (POD)-like synthase. Experimental exposure of plants to different concentrations of H₂O₂ showed that endogenous H₂O₂ and alkaloid concentrations in leaves were positively elevated. The time-course variations of alkaloid concentrations and redox state, reflected by the concentrations of H₂O₂, ascorbic acid (AA), oxidative product of glutathione (GSSG) and POD activity, were significantly altered due to H₂O₂ application. The further correlation analysis between alkaloids and redox status indicated that VBL production was tightly correlated with redox status. These results provide a new link between VBL metabolisms and redox state in C. roseus.     

Increase in the indole alkaloid production and its excretion into the culture medium by calcium antagonists inCatharanthus roseus hairy roots

Treatment of Catharanthus roseus hairy roots with antagonists, like verapamil and CdCl₂, that block the Ca²⁺ flux across the plasma membrane enhanced the total alkaloid content by 25% and their secretion 10 times. The specific Ca²⁺ chelator, EGTA, stimulated 90% of the total alkaloid secretion. Treatment with inhibitors of intracellular Ca²⁺ movement, like TMB-8 and trapsigargin, enhanced the total alkaloid content by 74% and their secretion into the culture media by 4- to 6-fold. The results suggest that an inhibition of external and internal Ca²⁺ fluxes induces an increase in the indole alkaloid accumulation and secretion in C. roseus hairy roots.     

Gibberellic acid-induced changes in glutathione metabolism and anthocyanin content in plant tissue

Literature data point to a possible link between gibberellic acid (GA₃) and glutathione metabolism in plant tissue, as both are connected to dormancy breakage. In order to study the influence of GA₃ on glutathione metabolism, we treated an anthocyanin accumulating cell culture of periwinkle (Catharanthus roseus) and a shoot differentiated culture of pea (Pisum sativum) with GA₃. Glutathione reductase (GR; E.C. 1.6.4.2) activity increased to 135% and 190% of the control in C. roseus and P. sativum, respectively. The level of oxidized glutathione (GSSG) decreased to 60% of the control in the C. roseus culture while no change in GSSG was observed in the P. sativum culture. No changes in the tissue concentration of total glutathione was observed in the cultures after GA₃ treatment. Concomitant to the changes in GSSG and GR, an increase in anthocyanin accumulation was observed in the C. roseus culture in association with a strong increase in phenylalanine ammonia-lyase (PAL; E.C. 4.3.1.5) activity in response to GA₃. These data strongly suggest a link between GA₃ and glutathione metabolism.     

The impacts of increased nitrate supply on Catharanthus roseus growth and alkaloid accumulations under ultraviolet-B stress

It has been reported that nitrate availability was able to modify the detrimental effects induced by excess ultraviolet-B (UV-B) radiation on plants. In this study, the medical plant Catharanthus roseus was subjected to UV-B stress and altered levels of nitrate nutrition to investigate their influence in a sole or combined way on growth and alkaloid productions. Our results showed that the UV-B stress obviously inhibited growth and led to damages of oxidative stress and lipid peroxidation. The simultaneous supply of higher nitrate nutrition could largely alleviate the inhibitory effects and damage symptom under the UV-B stress in C. roseus. Meanwhile, the UV-B-absorbing compounds as well as three alkaloids, vinblastine, vindoline, and catharanthine, were observed to have a remarkable elevation. These compounds were considered to serve as protectants of UV-B radiation. It was concluded that an increased nitrogen (N) supply could not only alleviate the inhibitory effect of UV-B stress on plant growth, but also enhance the accumulation of pharmaceutically used alkaloid in these plants. We proposed that the enrichment of N nutrition might provide more N source for alkaloid synthesis induced by UV-B radiation, eventually resulting in an increase of alkaloids accumulation.     

Effect of terpenoid precursor feeding and elicitation on formation of indole alkaloids in cell suspension cultures of Catharanthus roseus

The effects of terpenoid precursor feeding and elicitation by a biotic elicitor on alkaloid production of Catharanthus roseus suspension cultures were studied. After addition of secologanin, loganin or loganic acid an increase in the accumulation of ajmalicine and strictosidine and a decrease of tryptamine level was observed in non-elicited cells. Elicitation increased tryptamine accumulation in non-fed cells but it did not further increase alkaloid accumulation in precursor-fed cells. A decrease of tryptamine level was also observed, despite the induction of the tryptamine pathway after elicitation. Feeding mevalonic acid did not increase alkaloid accumulation in any studied case.     

Influence of mitochondrial genome rearrangement on cucumber leaf carbon and nitrogen metabolism

The MSC16 cucumber (Cucumis sativus L.) mitochondrial mutant was used to study the effect of mitochondrial dysfunction and disturbed subcellular redox state on leaf day/night carbon and nitrogen metabolism. We have shown that the mitochondrial dysfunction in MSC16 plants had no effect on photosynthetic CO₂ assimilation, but the concentration of soluble carbohydrates and starch was higher in leaves of MSC16 plants. Impaired mitochondrial respiratory chain activity was associated with the perturbation of mitochondrial TCA cycle manifested, e.g., by lowered decarboxylation rate. Mitochondrial dysfunction in MSC16 plants had different influence on leaf cell metabolism under dark or light conditions. In the dark, when the main mitochondrial function is the energy production, the altered activity of TCA cycle in mutated plants was connected with the accumulation of pyruvate and TCA cycle intermediates (citrate and 2-OG). In the light, when TCA activity is needed for synthesis of carbon skeletons required as the acceptors for NH₄ ⁺ assimilation, the concentration of pyruvate and TCA intermediates was tightly coupled with nitrate metabolism. Enhanced incorporation of ammonium group into amino acids structures in mutated plants has resulted in decreased concentration of organic acids and accumulation of Glu.     

钾肥类型对菜心(菜薹)生长、细胞保护酶和内源激素的影响

为探讨钾肥类型对菜心(Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee)的作用效应,研究了不同钾肥类型和水平对菜心生长、细胞保护酶和内源激素的影响。结果表明,氯化钾或硫酸钾处理可提高菜心叶片的POD 和CAT 活性、IAA 和GA₃ 含量,降低MDA 含量,提高菜薹产量。随着钾水平的提高,叶片IAA 和GA₃ 含量、POD 和CAT 活性以及菜薹质量明显提高,MDA 含量降低。当施钾90 kg hm^-2 时,叶片的GA₃ 和IAA 含量显著下降,而POD 活性和菜薹产量没有显著变化。在相同水平下,氯化钾与硫酸钾对植株生长、菜薹产量、叶片GA₃ 含量的影响不显著。当施钾0~90 kg hm^-2 时,氯化钾处理的叶片POD 活性显著高于硫酸钾处理;而施钾135~180 kg hm^-2 时,氯化钾处理的叶片POD 活性则显著低于硫酸钾处理。除了90 kg hm^-2 氯化钾处理的CAT 活性和45 kg hm^-2 氯化钾处理的MDA 含量低于硫酸钾处理以及90 kg hm^-2 和180 kg hm^-2 氯化钾处理的IAA 含量高于硫酸钾处理的外,相同水平氯化钾和硫酸钾处理的CAT 活性、MDA 含量和IAA 含量没有显著差异。可见,钾肥类型对菜心的活性氧代谢系统及内源激素含量有一定的影响,但氯化钾与硫酸钾对菜心的施用效果相当,生产上可采用氯化钾代替硫酸钾以节约肥料成本,K₂O 施用量以90 kg hm^-2 为宜。     

Catharanthine and ajmalicine synthesis in Catharanthus roseus hairy root cultures

Two year old, transformed root cultures of Catharanthus roseus accumulate ajmalicine and catharanthine (0.57 and 0.36 mg g^-1 DW, or 7.0 and 3.0 mg l^-1, respectively). Changes in the concentration of the medium components, as well as the addition of hydrolytic enzymes and biotic elicitors, were used as strategies to increase these alkaloid yields. Regarding the components of the medium, the results obtained, when sucrose was raised from 3 to 4.5%, are noteworthy. The nitrogen source induced differential responses in the individual alkaloid yields. No net change in the alkaloid content was observed either with changes in the concentration of vitamins or macro-and micronutrients. Though the root culture only shows a limited response to elicitors, Aspergillus treatment and the use of macerozyme increased the accumulation of ajmalicine selectively, while the addition of methyl jasmonate increased the yield of both alkaloids.Abbreviations MeJa methyl jasmonate - mU milliunits     

The role of the octadecanoid pathway in the production of terpenoid indole alkaloids in Catharanthus roseus hairy roots under normal and UV‐B stress conditions

The octadecanoid pathway is responsible for producing jasmonic acid an important signaling molecule in plants, which controls the production of a variety of secondary metabolites. Previously the exogenous addition of jasmonic acid to Catharanthus roseus hairy roots caused an increase in terpenoid indole alkaloid (TIA) accumulation. The role of the endogenous production of jasmonic acid by the octadecanoid pathway in the production of TIAs in C. roseus hairy roots is examined. Feeding of octadecanoid pathway inhibitors suggests that the octadecanoid pathway does not actively control TIA production under normal growth conditions or during the UV‐B stress response in C. roseus hairy roots. Biotechnol. Bioeng. 2009;103: 1248–1254. © 2009 Wiley Periodicals, Inc.     

Drought and warming induced changes in P and K concentration and accumulation in plant biomass and soil in a Mediterranean shrubland

A field experiment involving drought and warming manipulation was conducted over a 6-year period in a Mediterranean shrubland to simulate the climate conditions projected by IPCC models for the coming decades (20% decreased soil moisture and 1°C warming). We investigated P and K concentration and accumulation in the leaves and stems of the dominant species, and in soil. Drought decreased P concentration in Globularia alypum leaves (21%) and in Erica multiflora stems (30%) and decreased K concentration in the leaves of both species (20% and 29%, respectively). The general decrease of P and K concentration in drought plots was due to the reduction of soil water content, soil and root phosphatase activity and photosynthetic capacity that decreased plant uptake capacity. Warming increased P concentration in Erica multiflora leaves (42%), but decreased it in the stems and leaf litter of Erica multiflora and the leaf litter (33%) of Globularia alypum, thereby demonstrating that warming improved the P retranslocation and allocation from stem to leaves. These results correlate with the increase in photosynthetic capacity and growth of these two dominant shrub species in warming plots. Drought and warming had no significant effects on biomass P accumulation in the period 1999–2005, but drought increased K accumulation in aboveground biomass (10 kg ha⁻¹) in Globularia alypum due to the increase in K concentration in stems. The stoichiometric changes produced by the different responses of the nutrients led to changes in the P/K concentration ratio in Erica multiflora leaves, stems and litter, and in Globularia alypum stems and litter. This may have implications for the nutritional value of these plant species and plant–herbivore relationships. The effects of climate change on P and K concentrations and contents in Mediterranean ecosystems will differ depending on whether the main component of change is drought or warming.     

Potassium enhances the sugar assimilation in leaves and fruit by regulating the expression of key genes involved in sugar metabolism of Asian pears

Potassium (K) plays an important role in fruit quality, and is well known as the most important quality element. A field experiment was conducted with four K levels of 0 (control), 150 (K150), 300 (K300), 450 (K450) kg K₂O ha^?1 in 2014–2015. The aim was to elucidate the roles of K in fruit growth, and the mechanism of K in regulating sugar metabolism between the leaves and fruit of Asian pear (Pyrus L.). The results showed that the K concentration and accumulation in leaves and fruit with the net photosynthetic rate and SPAD value of leaves were found to increase with the increase of K application rates. Increasing K application rates also led to promote the effectiveness of accumulation of glucose, fructose, sorbitol, and sucrose in fruit. During the early fruit development stage, the increase of all soluble sugars in leaves was correlated with the up-regulation expression of gene AIV and S6PDH. Furthermore, with fruit development, the expression of AIV1, SPS1 and SUS, S6PDH and SDH3 involved in sugar metabolism in leaves were up-regulated by increasing the K application rates, resulting in higher accumulation of soluble sugars in leaves. Interestingly, at the fruit maturity stage the expression of SUT in leaves, and SPS1, SUS and SUT in fruit was significantly up-regulated, leading to higher sucrose accumulation in fruit. Thus, K-promoted sugar accumulation of the leaves and fruit might result from up-regulated expression levels of key genes involved in sugar metabolism by K in leaves and fruit.     

A virus-induced gene silencing approach to understanding alkaloid metabolism in Catharanthus roseus

The anticancer agents vinblastine and vincristine are bisindole alkaloids derived from coupling vindoline and catharanthine, monoterpenoid indole alkaloids produced exclusively by the Madagascar periwinkle (Catharanthus roseus). Industrial production of vinblastine and vincristine currently relies on isolation from C. roseus leaves, a process that affords these compounds in 0.0003–0.01% yields. Metabolic engineering efforts to either improve alkaloid content or provide alternative sources of the bisindole alkaloids ultimately rely on the isolation and characterization of the genes involved. Several vindoline biosynthetic genes have been isolated, and the cellular and subcellular organization of the corresponding enzymes has been well studied. However, due to the leaf-specific localization of vindoline biosynthesis, and the lack of production of this precursor in cell suspension and hairy root cultures of C. roseus, further elucidation of this pathway demands the development of reverse genetics approaches to assay gene function in planta. The bipartite pTRV vector system is a Tobacco Rattle Virus-based virus-induced gene silencing (VIGS) platform that has provided efficient and effective means to assay gene function in diverse plant systems. A VIGS method was developed herein to investigate gene function in C. roseus plants using the pTRV vector system. The utility of this approach in understanding gene function in C. roseus leaves is demonstrated by silencing known vindoline biosynthetic genes previously characterized in vitro.     

Cultivation, mineral nutrition and seed production of Catharanthus roseus (L.) G. Don in the temperate climate zone

The following aspects of Catharanthus roseus (L.) G. Don cultivation are covered in this chapter: climatic and soil requirements, agricultural measures, including propagation, sowing, planting, fertilization, irrigation and harvest date. The influence of these parameters on quality of herb material and alkaloid concentration is also discussed. Although tropical and subtropical zone have been reported as the most suitable for the cultivation of Catharanthus roseus, it seems to be possible to grow it also under other climatic conditions. However then, adequate conditions should be provided, according to the specific requirements of this species. Proper air temperature and humidity as well as sufficient soil moisture during growth, development and seed set are important factors for growing of Catharanthus roseus in the temperate zone. Albeit it may tolerate unfavourable environment conditions such as drought or salinity, its yield may be reduced considerably. Special attention has been paid in this paper to the effect of different ways of fertilization on alkaloid yield.     

Arbuscular mycorrhizal fungi and potassium bicarbonate enhance the foliar content of the vinblastine alkaloid in Catharanthus roseus

Vinca (Catharanthus roseus (L.) G. Don.) is an important medicinal plant species from which antineoplastic alkaloids such as vinblastine are extracted. However, neither abiotic stress nor inoculation of arbuscular mycorrhizal fungi (AMF) has been evaluated on the accumulation of vinca alkaloids under controlled conditions. This study evaluated the effects of AMF and/or abiotic stress induced by the application of potassium bicarbonate (KHCO₃) and/or sodium chloride (NaCl) on plant growth, and on total content of phenolic compounds (TCPC), total antioxidant activity (TAOX), and total content of vinblastine alkaloid in leaves of vinca. TCPC, TAOX, and vinblastine were measured via spectrophotometric methods. After 75 days under greenhouse conditions, either the AMF inoculation without abiotic stress or the application of KHCO₃ (2.5 and 7.5 mM) resulted in significantly (P?≤?0.001) enhanced plant growth, TCPC, TAOX, and total content of vinblastine. The application of NaCl significantly diminished plant growth, but did not stimulate the content of vinblastine. The combined application of NaCl and KHCO₃ significantly decreased AMF-colonization in roots. The sole inoculation of AMF or the single application of 7.5 mM KHCO₃ induced the accumulation of vinblastine in leaves of vinca.     

Growth responses of <Emphasis Type="Italic">Sagittaria sagittifolia</Emphasis> L. plants to water contamination with cadmium

Cadmium accumulation, the relative content of different chemical forms of Cd, as well as the toxic effect of Cd on nutrient element uptake, physiological parameters, and ultrastructure of Sagittaria sagittifolia L. seedlings were determined after the seedlings were exposed to different Cd concentrations for 4 days. The results showed that S. sagittifolia had the ability to accumulate large amounts of Cd. In the root, stem, and bulb, the predominant chemical Cd forms were NaCl extractable. With an increase in the Cd²⁺ concentration, the chlorophyll content, the relative membrane penetrability (RMP) of root cells, peroxidase (POD) activity, superoxide dismutase (SOD) activity in leaves, malondiadehyde (MDA) content and the superoxide anion (O₂⁻) generation rate in roots all decreased following an initial increase. On the other hand, catalase (CAT) activity, SOD activity in roots, MDA content, and the generation rate of O₂⁻ in leaves all increased gradually. The toxic effect of Cd²⁺ was more severe on roots than on leaves at the same concentration. Cadmium affected the mineral nutrition balance; mainly, it promoted the uptake of Ca, Cu, Mn, and Fe, while inhibited Mg, Na, and K uptake. The physiological toxic effect of Cd²⁺ was close to the ultrastructural damage induced by Cd contamination. A significant correspondence was observed between the Cd dose and its toxic effect. Cadmium could destroy the normal ultrastructure, disturb the ion balance, and interfere with cell metabolism.     

Annuario della Società Botanica Italiana 1932

A sandy culture experiment was conducted to investigate the effects of exogenous CaCl₂ on the indole alkaloid accumulation in Catharanthus roseus under salt stress. One-month seedlings of C. roseus were treated with the different concentrations of NaCl (0, 50, and 100 mmol l^? 1) and 7.5 mmol l^? 1 CaCl₂. The plant samples were analyzed after 7 days of the treatments. The NaCl-stressed plants showed decrease of fresh and dry weight and increase of malondialdehyde (MDA) content compared to control. Tryptophan decarboxylase (TDC) activity increased significantly under 50 mmol l^? 1 NaCl without CaCl₂ addition, 50 mmol l^? 1 NaCl with 7.5 mmol l^? 1 CaCl₂, and CaCl₂ treatment without NaCl addition. There was a significant increase in peroxidase activity under NaCl stress compared to control. The vindoline, catharanthine, vincristine, and vinblastine contents increased under salt stress (especially with 50 mmol l^? 1 NaCl treatment with or without CaCl₂). Addition of CaCl₂ to NaCl-stressed plants increased biomass, TDC activity, vindoline, and catharanthine contents and lowered MDA and vincirstine contents compared to the plants without CaCl₂. The plants treated with CaCl₂ alone showed higher TDC activity, vindoline, catharanthine, and vinblastine content when compared to control. The results showed that exogenous CaCl₂ could promote the indole alkaloid metabolism under salt stress.