香石竹保鲜技术研究进展

从水分代谢、呼吸代谢、植物生长调节剂等几个方面分析香石竹采后衰老的原因,总结出目前香石竹采后保鲜所采用的方法,并提出香石竹保鲜技术的未来发展方向,以期为香石竹的切花保鲜研究提供参考.     

香石竹试管苗移栽基质的筛选

试管苗的移栽驯化是快繁过程中的关键一步,其中移栽基质是影响试管苗驯化成活的重要因素之一,只有选取适宜的移栽基质,创造良好的环境条件,才能培育出优质苗[1].目前,我国已对许多植物试管苗的移栽进行了研究,并以蛭石、珍珠岩等作为较理想的育苗基质[2～5].     

Effect of benzyladenine, 4-PU-30 and thidiazuron on millisecond delayed and prompt chlorophyll fluorescence of Dianthus caryophyllus L. axillary buds cultured in vitro

The effects of benzyladenine (BA) and two phenylurea cytokinins (N-phenyl-N′-(2-chloro-4-pyridyl)urea (4-PU-30) and thidiazuron (TDZ)) on in vitro cultures of carnation were studied using induction kinetics and thermograms of prompt and delayed chlorophyll fluorescence. In plantlets obtained from explants cultivated on a medium with 0.4 μM BA or 0.04–0.004 μM phenylurea cytokinins, the photosynthetic apparatus showed high PS II photochemical activity comparable to control without cytokinins and 5.8–97.5% higher estimated photoinduced transmembrane proton gradient (low concentrations of 4-PU-30 are especially effective). At a concentration of 0.4 μM, when compared to BA treatment, phenylurea cytokinins induced 24–35% suppression of photochemical activity, 44–46% suppression of estimated transmembrane proton gradient and 12–17% suppression of estimated electron transport rate. It is likely that this concentration of phenylurea cytokinins exceeded the optimal dose. The analysis of the same luminescent characteristics in the presence of different 4-PU-30 and TDZ concentrations showed that these compounds induced dose-dependent changes in the functional activity as well as alteration in the level of energization of the thylakoid membrane. When fluorescence thermograms were evaluated, phenylureas appeared to change the high-temperature stability of the photosynthetic apparatus.     

外源硫化氢对康乃馨切花叶绿素荧光参数和抗氧化酶活性的影响

以康乃馨(Dianthus caryophyllus L.)切花为试材,瓶插液中加入不同浓度的硫化氢(H_2S)供体硫氢化钠(NaHS),以蒸馏水处理为对照,研究H2S对康乃馨叶片叶绿素荧光参数和抗氧化酶活性的影响,以期探讨外源硫化氢(H_2S)对康乃馨切花保鲜的调控机理。结果表明:在康乃馨切花衰老过程中,叶片叶绿素含量、可溶性糖含量降低,暗下光系统Ⅱ最大光化学效率(Fv/Fm)、潜在活性(Fv/Fo)、光下实际光化学效率ΦPSⅡ降低。与对照相比,适宜浓度的NaHS溶液能延长切花寿命,增大花径,增加叶片可溶性糖、叶绿素含量,Fv/Fm、Fv/Fo、ΦPSⅡ明显升高。其中,以600μmol·L~(-1) NaHS溶液处理的效果最好。瓶插第4天600μmol·L~(-1) NaHS溶液处理的丙二醛(MDA)含量显著低于对照,而超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著高于对照。可见,外源H2S可增强康乃馨切花衰老时活性氧清除能力,减轻叶片光合结构的伤害,延长花期,提升观赏价值。     

Video evaluation of ethylene sensitivity after anthesis in carnation (Dianthus caryophyllus L.) flowers

Differences in ethylene sensitivity among carnation (Dianthus caryophyllus L.) cultivars were evaluated using a time-lapse video recording system. Measurement of time to petal inrolling of ‘White Sim’, ‘Nora’, ‘Chinera’, and line 64-54 flowers subjected to a range of 1–20 μl l⁻¹ ethylene showed that 10 μl l⁻¹ was the optimum concentration for sensitivity evaluation with our video system. With this system we found clear differences in ethylene sensitivity among 10 cultivars and one line. ‘Candy’, ‘Pallas’, ‘Chinera’, and line 64-54 had lower ethylene sensitivities than the other seven cultivars. Line 64-54 had the longest ethylene response time (20.6 h to start of petal inrolling). Video monitoring is a simple and accurate way of evaluating ethylene sensitivity. We have also used the system to study changes in the ethylene sensitivity of carnation flowers after anthesis. We were able to detect a shift in responsiveness to ethylene that was impossible to detect by previous methods. In the Sim-type carnation cultivars tested (‘White Sim’, ‘Scania’, ‘U Conn Sim’, and ‘Nora’), ethylene sensitivity after anthesis decreased significantly with age in both early-cut and late-cut flowers. These results clearly showed that decline of ethylene sensitivity is caused by the increasing physiological age of flowers. Ethylene sensitivity after anthesis decreased with age in normal Sim-type carnations in the same way as in long-vase-life variants such as ‘Sandrosa’.     

Direct shoot organogenesis on shoot apex from seedling explants of Capsicum annuum L.

In vitro direct multiple shoot formation from seedling explants of Indian high pungent varieties of Capsicum annuum cv. Arka Abhir (AA) and Arka Lohit (AL) was successfully obtained. We were able to induce regeneration potency in these varieties by inverting the explant. Aseptically grown seedling explants with decapitated roots, apical meristem and cotyledonary leaves were inoculated in an inverted position in bud induction medium comprising of Murashige and Skoog's basal medium supplemented with 2-(N-morpholine) ethanesulphonic acid (MES) buffer along with 26.63 μM benzyl adenine (BA), 2.28 μM indole-3-acetic acid (IAA) and 10 μM silver nitrate. Profuse shoot bud induction with 20–25 shoot buds per explant was obtained. Supplementation of phloroglucinol in the bud induction medium resulted in 17 and 18% enhancement in bud induction response in Arka Abhir and Arka Lohit variety, respectively on the inverted hypocotyls. Auxin transport inhibitor tri-iodo benzoic acid (TIBA) in the bud induction medium resulted in induction of buds in a shorter period of 40–45 days when compared to bud induction (BI) medium which takes 55–65 days for bud induction. These buds were transferred to MS medium containing 2.8 μM gibberellic acid and 10 μM silver nitrate resulting in elongation of shoot buds. Transfer of shoots to MS basal medium induced rooting to produce plantlets. This protocol can be efficiently used for mass propagation and presumably also for regeneration of genetically transformed C. annuum tissues.     

不同时期及部位的外植体对香石竹芽形成的影响

在春、冬季取香石竹的顶芽、茎段芽进行离体培养,研究不同采集季节及部位的外植体对香石竹芽形成的影响。结果表明:在春季取顶芽做外植体采用70%酒精30s+0.1%升汞6min消毒处理可获得较好的试管苗。70%酒精30s+0.1%升汞6min较适宜于外植体消毒,在春季取材,顶芽分化优于茎段芽,在冬季取材,茎段芽分化优于顶芽。     

Direct somatic embryogenesis and adventitious shoot formation from immature axillary buds of Melastoma affine

Summary

Direct somatic embryogenesis and adventitious shoot formation were induced from immature axillary bud explants of Melastoma affine cultured on induction medium containing both naphthaleneacetic acid (NAA) and cytokinins. Among the cytokinins tested, thidiazuron (TDZ) played a greater role in the induction of somatic embryogenesis than 6-benzylaminopurine (BA) and kinetin (KT). Histological studies of paraffin sections showed that the same tissue from immature axillary buds produced different types of explants that developed floral primordia and vegetative bud primordia during the earlier and later flowering stages, respectively. These could result in different developmental pathways. Efficient mass propagation and plant regeneration systems were established for Melastoma affine.     

In situ micro-spectrophotometric and micro- spectrocolorimetric investigation of vacuolar pigments in flowers of cultivars of carnation (.Dianthus caryophyllus)

Living epidermal cells of flower petals of carnations have been surveyed for their native colour by in situ spectral (350-750 nm wavelengths) and colorimetric investigations (CIE- Lab, L* C* h system) of their vacuolar pigment content with a micro-spectrophotometer. Vacuolar solutions in cultivars with yellow based colours generally display high Absorbances (close to, or over A = 2 under a 25 |xm optical depth) in the near-UV area only: at 360-375 nm for ivory or pale yellow colours (flavonols only) and additionally at 380- 395 nm (chalcone glycosides) for yellow ones. Carnation cultivars with cyanic colours are accumulating anthocyanins, namely monosides and diosides of pelargonidin and cyani- din, along with flavonol glycosides acting as co-pigments. Besides their main À.max in the 520-550 nm area, frequently appearing at lower wavelengths than in those of diosides, spectra of solutions of monosides are characterized by an additional peak or shoulder around 450 nm. Cyanidin derivates often exhibit higher X.max wavelengths than those recorded in spectra of corresponding pelargonidin derivates. In the spectra of solutions of most classes of these anthocyanins, the visible Xmax position varies considerably, according to the relative concentrations of pigment (measured as the Absorbance at the visible Àmax) to co-pigment (appreciated by the Absorbance at the near-UV Xmax): generally, the higher this ratio, the longer is the visible Xraax wavelength. In situ spectral recording of individual vacuolar sap also reveals that different cells in the same petal epidermis are accumulating, in some cultivars, distinct pigment mixtures (diosides vs. monosides for instance) originating different colours. Colours of the vacuolar solutions have been colorimetrically described in the CIELab system in terms of hue (hab), saturation (Chroma, C*) and intensity (Lightness, L*). Generally, as the Absorbance at X.max, i.e. the pigment concentration, increases, Lightness decreases accordingly. Chroma mainly depends on the general shape of the spectra in the visible area. The more complex relationships of hue with spectral characteristics and the nature of the pigment mixture are discussed. Finally, the comparison of L* C* h colorimetric data calculated for two CIE illuminants (D65 and A) shows how the same pigment mixture (and consequently the further colour of intacts petals) appears to be coloured differently according to the lighting conditions of the visual observation.     

Plant regeneration of Nerium oleander L. from alginate-encapsulated shoot explants after short-term cold storage

In this study, an efficient protocol for the regeneration of encapsulated explants of oleander (Nerium oleander L.) has been developed. Shoot tips and 1st nodal segments below the shoot tip, from in vitro-derived oleander microshoots, were encapsulated in 2.5% sodium alginate prepared in liquid MS sucrose-free nutrient medium and hardened in 50 mM of calcium chloride producing solid beads, uniform in shape. These artificial seeds, irrespective of their maintenance under light or in darkness, germinated at frequencies of 38.8–42.2%, producing 3.0–3.3 microshoots per bead. In the case of using 100 mM of calcium chloride for hardening, the beads were firm, of uniform globular shape and suitable for handling, exhibiting a germination response of 68.9%. Encapsulated shoot tip explants, following storage at 4°C for 8 weeks, exhibited a higher regeneration response (60.0%) than non-encapsulated similar explants stored under the same conditions (11.1%). Microshoots, excised from cold-stored encapsulated explants after germination, rooted easily in agar-solidified MS medium with 2 μΜ IBA and after their transplantation into a peat-perlite substrate (3:1, v/v), were acclimatised successfully and established in the greenhouse with minimal losses. The present encapsulation procedure could be applied as an alternative method of micropropagation of desirable elite clones of oleander.     

石竹花芽发生与内源多胺含量的关系

以石竹叶片为外植体,诱导愈伤组织、营养芽、花芽的培养基分别为ＭＳ＋ＺＴ２．５ｍｇ／Ｌ＋２,４－Ｄ０．３ｍｇ／Ｌ;ＭＳ＋ＺＴ１ｍｇ／Ｌ＋ＢＡ２ｍｇ／Ｌ＋ＮＡＡ０．２ｍｇ／Ｌ;ＭＳ＋ＩＢＡ０．５ｍｇ／Ｌ＋ＮＡＡ０．３ｍｇ／Ｌ。在石竹离体叶花芽形成过程中,内源多胺含量呈不同的变化趋势,腐胺、亚精胺含量上升,而二丙胺、精胺含量下降,表明多胺与石竹离体叶花芽分化有明显的内在联系。     

In vitro plantlets from alginate-encapsulated shoot tips of Solanum nigrum L.

Shoot tip explants obtained from in vitro proliferated shoots were encapsulated in 3% sodium alginate and 100 mM calcium chloride for the production of synthetic seed in Solanum nigrum L., a medicinally important plant. Morphogenic responses of encapsulated shoot tips to various sowing media (full or half-strength 0.8% agar-solidified or liquid MS medium or full-strength MS medium containing BAP) were evaluated in vitro. Of the six media evaluated, maximum conversion was obtained on 0.8% agar-solidified growth regulator free full-strength MS medium. The addition of MS nutrients in alginate matrix had a pronounced effect on the length of shoots that emerged from alginate beads. Encapsulated shoot tips also converted when directly sown in sterile soil moistened with liquid MS medium. Encapsulated shoot tips could be stored at low temperature (4 °C) up to 60 days. Plantlets regenerated from encapsulated shoot tips were acclimatized successfully.     

人心果转录组De novo组装及奇可胶途径相关基因的分析

为了探索人心果(Manilkara zapota L.)的转录组及奇可胶合成相关的基因,使用Illumina测序平台,对人心果果实、树皮和叶片分别进行转录组测序,使用Trinity等软件进行De novo组装和注释以及计算表达量,采用实时荧光定量PCR对转录组数据进行验证。经过组装得到162 455条unigene,总长度达139 792 553 nt,平均长度达861 nt,N50达1 544 nt。通过与NR、NT、Swiss-Prot、KEGG、COG和GO等数据库比对,共计89 628条unigene得到注释。以组装出来的unigene作为参考序列,在人心果转录组中共鉴别出57 362个SSR位点,果实、叶片和树皮表达的基因中分别检测到99 925、65 989和129109个SNP位点。在人心果转录组中共鉴别出105个与奇可胶合成相关的unigene,参与甲羟戊酸(MVA)途径的基因在果实和树皮中表达量较高,磷酸盐(MEP)途径中的基因则在叶片中的表达量较高,实时荧光定量PCR结果与转录组计算得到的表达量一致。初步推测MVA途径可能是奇可胶合成的主要途径。     

Effect of Season on the Carnation (Dianthus Caryophyllus L.) I. Growth Rate

The effect of seasonal variation in the glasshouse environment on the initial growth rate of the carnation has been determined from the increase in dry weight of rooted cuttings of the cultivar White Sim grown for a 27-day period ; observations were repeated at 14-day intervals over a period of one year.

Absolute growth rates varied over the season by a factor of ten, values ranging from approximately 0.01 g day^-1 in winter to 0.1 g day^-1 in summer. Growth rate was found to be a linear function of the mean daily radiation flux density during the growing period; shade-grown plants which received only 50% of the normal radiation showed a corresponding reduction in growth rates. The regression coefficients of absolute growth rate on radiation were similar for both full-light and shade-grown plants. Absolute growth rates showed a curvilinear relationship with respect to the glasshouse mean air temperature.

Relative growth rates of plants grown under full radiation ranged from 1% per day in winter to 4.5% per day in summer.     

Effects of pruning intensity on the biochemical status of shoot buds in three mango (Mangifera indica L.) cultivars planted at high density

Summary

Mango (Mangifera indica L.) trees grown at high density show a decline in flowering and fruiting after good fruiting years as a result of various factors. Annual pruning can restore production and productivity in such trees. Chlorophyll, total sugars (TS), total phenolics (TP), and proline contents as well as polyphenol oxidase (PPO) activities, were measured in the 2005–2006 and 2006–2007 seasons in shoot buds with a few leaves in three mango cultivars (‘Amrapali’, ‘Mallika’, and ‘Dashehari’). Trees were grown at high density in an orchard and the aforesaid parameters were measured 1 month after different degrees of pruning (Stage I) and after subsequent fruit bud differentiation (FBD; Stage II). Severely-pruned mango trees had the highest contents of chlorophyll a, while chlorophyll b and total chlorophyll contents were found to be highest in moderately-pruned trees. Lightly-pruned trees had the highest contents of reducing sugars (RS), whereas TS contents were highest in severely-pruned trees. The contents of RS and TS increased in shoot buds during the FBD stage. A moderate intensity of pruning significantly increased TP contents, while the lowest TP contents were recorded in non-pruned trees. ‘Off’-year shoots had higher TP contents than ‘on’-year shoots. Irrespective of pruning intensity, shoot buds of ‘Mallika’ trees had the highest PPO activities, with lower levels in ‘Amrapali’ and ‘Dashehari’ shoot buds. PPO activities were reduced at the FBD stage in ‘on’-year shoots. Severely-pruned trees had the highest PPO activities, while the lowest PPO activities were recorded in lightly-pruned trees. Shoot bud proline contents were found to be highest in non-pruned trees, and decreased with increasing pruning intensity. Thus moderate pruning can be adopted in high density orchards to obtain sustainable production with improved maintenance of canopy architecture.     

Micropropagation of Capsicum frutescens L. using axillary shoot explants

A novel micropropagation protocol was established for Capsicum frutescens L. cv. ‘Uchithi’, a pungent chilli cultivar, through induction of axillary shoot proliferation of in vitro raised plantlets by decapitation and using the axillary shoots as explants for multiple shoot bud induction. About 2–6 axillary shoots were induced within 2 weeks when 4-week-old in vitro raised plantlets were decapitated. The axillary shoot-tip explants produced multiple shoot buds when cultured on Murashige and Skoog's (MS) medium containing 8.8–44.4 μM 6-benzylaminopurine (BAP) or 9.3–46.7 μM kinetin alone or 8.8–44.4 μM BAP with 4.6 μM kinetin or 5.7 and 28.5 μM indole-3-acetic acid (IAA). Maximum number of shoots (5.6) were induced on medium containing 22.2 μM BAP in combination with 4.65 μM kinetin. The separated shoots rooted and elongated on medium containing 2.8 μM IAA or 2.4–4.9 μM indole-3-butyric acid (IBA). Rooted plantlets were successfully established in the soil. Efficient mass multiplication of this important food crop was achieved.     

Direct shoot organogenesis on hypocotyl explants from in vitro germinated seedlings of Psidium guajava L. cv. Allahabad Safeda

Multiple shoots were generated via direct organogenesis on hypocotyl segments excised from in vitro germinated seedlings (45-day-old) of Psidium guajava L. cv. Allahabad Safeda. Modified basal Murashige and Skoog (MMS) medium supplemented with 6-benzylaminopurine (BAP), zeatin or thidiazuron with or without α-naphthalene acetic acid (NAA) were tried. Thidiazuron (0.1 μM) along with 0.54 μM NAA gave the highest response (44.6%) with the regeneration of 3.6 shoots per original explants. These shoots upon subculture gave rise to about 5.0 shootlets per explant in shoot proliferation medium, i.e. MMS supplemented with 2.22 μM BAP + 2.32 μM kinetin. The regenerated microshoots were elongated using a quick dip of gibberellic acid (GA₃; 1.44 mM) prior to culture on MMS medium supplemented with 0.88 μM BAP and adenine sulphate (54.29 μM) for 2 weeks. Rooting of microshoots was achieved best on half strength MMS medium supplemented with 4.90 μM indole-3-butyric acid along with 100 mg l⁻¹ activated charcoal.     

石竹试管花的诱导及其影响因子的研究

以石竹试管花的茎段为材料，研究了几种因子对试管花形成的作用。结果表明，开花植株的茎段可稳定地保持形成花芽的能力；外源激素对试管花的形成不是必需的因子。低浓度的生长素利于长根，对花芽的形成没有明显的影响，但较高浓度明显地抑制试管花的形成；细胞分裂素只促进营养芽的分化，完全抑制花芽的形成；所试培养基的各类和浓度除Ｎ６培养基外对花芽的作用没明显的差异；在缺ＮＨ４ＮＯ３的培养基中植株的营养生长受到抑制，植株变矮，叶片数减少，基部叶片发黄，植株提前开花，但不影响开花率。植株上部茎段比下部茎段形成花芽的频率高。     

Medium-term conservation of redwood (Sequoia sempervirens (D. Don.) Endl.) in vitro shoot cultures and encapsulated buds

This study evaluated the survival and recovery of non-encapsulated and encapsulated shoots of Sequoia sempervirens after storage at 4 °C in the dark for up to 15 months on four different culture media. Survival and regrowth of encapsulated shoots declined within 3 months, regardless of the storage medium composition. By contrast, no significant decrease in survival and regrowth was noted with non-encapsulated shoots after 12 months of storage on Quoirin and Lepoivre medium supplemented, or not, with 1 mg l⁻¹ benzyladenine. Regrowth dropped to 60–61% after 15 months of storage on the same media. Medium-term conservation of S. sempervirens germplasm is therefore possible using in vitro storage of non-encapsulated shoot cultures.     

Micropropagation of fastigiate bird cherry (Prunus padus L.) and adventitious shoot formation from leaves

A shoot tip of a mature clone of fastigiate bird cherry (Prunus padus L.) was successfully established in vitro. Culture of shoot tip explants on a Murashige and Skoog (MS) based medium with phloroglucinol (PG) resulted in micropropagation, but the clonal line gradually became hyperhydric on this medium. This problem was overcome using PG- free medium based on either MS or Driver and Kuniyuki Walnut medium (DKW). Heavier cultures with more shoots were obtained on DKW medium with fructose or glucose rather than sucrose or sorbitol. Leaf explants placed on DKW basal medium with benzyladenine (BA) produced adventitious shoots. Addition of 1-naphthaleneacetic acid to media with BA increased regeneration. More leaves produced shoots on medium with sucrose or sorbitol rather than glucose or fructose. Adventitious shoots were excised and micropropagated. Shoots were rooted by insertion into DKW medium with indol-3yl- butyric acid, followed by transfer to hormone-free DKW. PG increased the proportion of shoots that produced adventitious roots.