Effects of lanthanum element on the rooting of loquat plantlet in vitro

We investigated the rooting rate, the number of roots, and the state of growth of loquat (Eriobotrya japonica Lindi) plantlet in medium where La(NO₃)₃ (0.5–100.O μmol/L) was added 20 d after transplanting. The activity of peroxidase, nitrate reductase, and the fresh weight of roots were determined 44 d after transplanting. The result showed that the optimum concentration of La(NO₃)₃ (1.0–3.0 μmol/L) in the rooted medium could increase the rate and the fresh weight of rooting, promote the length of root, and increase the activities of peroxidase and nitrate reductase.     

The effects of rooting frequency and position of rooted ramets on plasticity and yield in a clonal species: an experimental study with Glechoma hederacea

Clonal plants produce numerous ramets that can be distributed over a considerable area. Resources are translocated between ramets, especially when they occupy microsites of different quality, or places where leaves or roots cannot be deployed. It is common for a proportion of the ramets of clones and clonal fragments to lack roots. We conducted a greenhouse study using clonal fragments of Glechoma hederacea to examine the effects of differences in the number and position of rooted ramets on yield and plasticity of clonal fragments. We hypothesized that (1) mass of roots and root mass ratio would increase as the number of rooted ramets decreased, (2) plasticity in rooted ramets would buffer the clonal fragment against reduction in yield as the number of rooted ramets declined, (3) ramet plasticity in response to the absence of rooting, and the beneficial effects of this plasticity, would be greater when older ramets were rooted. The same yield was achieved in clonal fragments with only one out of four ramets rooted as in clonal fragments with all four of their ramets rooted, regardless of whether rooting was confined to older or younger ramets. Plasticity in biomass allocated to roots was greater in older rooted ramets succeeded by unrooted ramets than in younger rooted ramets preceded by unrooted ramets. Modular plasticity, involving both direct responses to local conditions, and indirect responses to the conditions experienced by connected modules, buffered performance against variation in rooting ability, enabling clonal fragments to maintain their yield and lateral expansion even when a high proportion of their ramets lacked roots.     

The relationship between rooting of poplar shoots and ATPase activity of their crude microsomal vesicles

Poplar shoots raised in vitro were induced to root by a 7 h passage on an auxin (1-naphthaleneacetic acid) medium. The percentage of rooting was reduced from ± 97% to ± 47% when vanadate (200 µM) was included in the auxin medium. Introduction of vanadate in the medium without auxin after the 7 h induction on auxin medium, did not inhibit rooting but affected only the development of the roots produced. The Mg²⁺-dependent ATPase activity of the microsomal vesicles of poplar shoots was increased after 7 h induction on rooting medium and corresponded to an increase in the Vmax of the enzyme. Results from experiments using some inhibitors of the polyamine metabolism suggested that this pathway was not involved in the increase of this activity. The auxin had no effect on the in vitro ATPase activity at any concentration tested except at about 2 mM where it was inhibitory, probably due to a change in the conformation of the enzyme. The transient increase of indole-3-acetic acid during rooting induction could be responsible for the increase in the level of the enzyme. The inhibition of root formation and growth by vanadate indicates strongly that the ATPase activity may be necessary for the induction and expression of rooting.     

影响喜树组织培养苗离体生根的因素

为了建立有效的喜树(Camptotheca acuminata)组培苗生根系统,提高其移栽成活率及适应性,用不同生长素种类及浓度、不同蔗糖浓度及不同培养基对喜树组培苗不定根形成影响以及移栽初期根系发育状况进行了研究.结果发现:1)生长素种类和浓度明显影响喜树组培苗不定根形成,在含有IBA0.5 mg·L-1培养基中取得了最佳生根效果,生根率达到了98%,外植体平均生根数为5.9条/株;2)不同浓度蔗糖对喜树组培苗生根也有一定影响,在10～30 g·L-1范围内,随着蔗糖浓度增加,生根百分率和生根数量都有增加,蔗糖浓度达到30 g·L-1时,生根百分率为95%,外植体平均生根数为5.4条/株;蔗糖浓度在40 g·L-1时,表现出对生根抑制作用;3)在基本培养基对喜树组培苗生根影响研究中发现,MS培养基对根形成表现出一定抑制作用;1/2MS和WPM培养基均适合喜树组培苗生根;4)根系发育正常的喜树组培苗移栽后成活率可达96%,但组培苗根系根毛系统发育较差.组培苗单位叶面积根尖数量显著低于对照实生苗,而且此参数与叶片气孔导度呈显著正相关.这种较差根系发育导致叶片气孔导度过低可能是组培苗叶片光合能力较低的重要原因.     

影响喜树组织培养苗离体生根的因素

为了建立有效的喜树(Camptotheca acuminata)组培苗生根系统,提高其移栽成活率及适应性,用不同生长素种类及浓度、不同蔗糖浓度及不同培养基对喜树组培苗不定根形成影响以及移栽初期根系发育状况进行了研究。结果发现: 1)生长素种类和浓度明显影响喜树组培苗不定根形成,在含有IBA0.5 mg.L-1培养基中取得了最佳生根效果,生根率达到了98%,外植体平均生根数为5.9条/株; 2)不同浓度蔗糖对喜树组培苗生根也有一定影响,在10~30 g.L-1范围内,随着蔗糖浓度增加,生根百分率和生根数量都有增加,蔗糖浓度达到30 g.L-1时,生根百分率为95%,外植体平均生根数为5.4条/株; 蔗糖浓度在40 g.L-1时,表现出对生根抑制作用; 3)在基本培养基对喜树组培苗生根影响研究中发现,MS培养基对根形成表现出一定抑制作用;1/2MS和WPM培养基均适合喜树组培苗生根; 4)根系发育正常的喜树组培苗移栽后成活率可达96%,但组培苗根系根毛系统发育较差。组培苗单位叶面积根尖数量显著低于对照实生苗,而且此参数与叶片气孔导度呈显著正相关。这种较差根系发育导致叶片气孔导度过低可能是组培苗叶片光合能力较低的重要原因。     

Promotion by phloroglucinol of adventitious root formation in micropropagated shoots of adult wild cherry (Prunus avium L.)

Micropropagated shoots of wild cherry (Prunus avium L.) produced roots in auxin-free medium. Phloroglucinol (PG) increased the proportion of shoots that rooted, while phloretic acid reduced this response in medium with or without PG, and cancelled the promotive effect of PG. Concentration of PG also significantly affected rooting in media with and without auxin. The proportion of shoots rooting in media containing auxin, or auxin plus PG, increased with the number of successive subculture, but the proportion that rooted with PG alone was unaffected by the number of subcultures. Before the shoots had become responsive to auxin, 1 mM PG was more effective than auxin in inducing root formation.     

云南山茶花茎尖培养中多芽体的形成和生根的研究

本文报道云南山茶花(Camellia reticulataL.)的茎尖培养诱导形成多芽体和生根的条件及影响因素。MS培养基中含有较高浓度(3—5 mgL~(-1))BA和适量(1—1.5 mgL~(-1))IAA或NAA诱导形成多芽体。外植体的母株年龄明显影响多芽体的形成,幼龄种苗外植体的多芽诱导率高于成年树。添加CM(椰乳)、ZT、尿囊素对成年芽条返幼态有明显的促进作用。采用“浸没-纸桥生根法”诱根,以高浓度生长调节剂(0.5gL~(-1)IBA或ABT生根粉)溶液浸芽条基部短时间(20—30 min),生根效果最佳。母树的年龄对芽条的生根也有显著影响,种苗来源的芽条的生根率和根的数目都比来源于成年树的高。生根培养基中蔗糖浓度为15—20 gL~(-1),生根率高。MW和1/2 ER培养基比MS培养基的生根效果好。试管植物移栽入土后生长正常并已开花。     

Clonal variability in root growth and drought resistance in tea (Camellia sinensis)

Summary An investigation was carried out to study whether differences in rooting depth, root weight and vertical distribution of roots in the soil were some of the factors responsible for clonal variation in drought resistance in tea. The results showed that of these factors only rooting depth influenced drought resistance. Shallow rooted clones were drought susceptible and deep rooted clones drought resistant. In shallow rooted clones drought resistance increased with rooting depth. However in deep rooted clones drought resistance was not related to rooting depth.     

Adventitious rooting performance in micropropagated Cornus mas

Axillary buds sampled from a mature 27-year-old Cornus mas cv. Macrocarpa were grown in vitro on modified woody plant medium (WPM). Adventitious rooting performance of microshoots was assayed on half-strength WPM supplemented with 1-naphthaleneacetic acid (NAA) or indole-3-butyric acid (IBA) under various pH. NAA induced significantly higher rooting frequencies than IBA. The pH of 6.8 inhibited rooting, and differentiated roots were extremely thick and fragile. The highest rooting frequency was recorded on half-strength WPM supplemented with 5.37 µM NAA at the pH value adjusted to 6.2 (73 % of rooted shoots). In the presence of IBA, the formation of adventitious roots was observed only in the basal part of the microshoot dipped into rooting medium. In the case of NAA, however, adventitious roots arose also from the parts of microshoots that were not in contact with medium. The growth of aerial roots was always positively gravitropic. The nuclear microsatellite Cf-G17 gave a monomorphic fingerprinting pattern across the mother shrub and micropropagated plantlets. Acclimatized plants did not show any visually detectable morphological variation and the aerial adventitious root formation was no longer observed.     

转抗盐基因八里庄杨组培苗快繁研究

以转1－磷酸甘露醇糖醇脱氢酶基因的八里庄杨为试材,筛选出了快繁的一系列培养基。分化培养基MS＋BA0.3mg.l^-1 IBA0.1mg.l^-1分化苗多,苗头密度高,叶色绿,并且可以节约对KT的使用。伸长培养基KT2.0mg.l^-1＋NAA0.1mg.l^-1使苗子伸长现象明显,苗子长势壮,叶子肥大。生根培养基以MS＋IBA0.2mg.l^-1为最佳,8天后开始生根,数量较多,生根后的试管苗生长粗壮,有利于移栽成活。以简化生根技术对杨树转化体进行生根试验,瓶外生根苗的移栽成活率明显比瓶内高,组培苗已成功移栽于大田中。     

In vitro rooting of micropropagated shoots from juvenile and mature Pinus pinaster explants: influence of activated charcoal

The ability for adventitious rooting of micropropagated shoots from juvenile and mature Pinus pinaster Ait. explants was assessed in vitro on a rooting expression medium. The different rooting traits observed, namely the rooting rate, the number and the length of the adventitious roots, and the root score, were greatly influenced by the age of the donor plant: 98% of juvenile explants rooted, while only 49% of mature explants did. Addition of activated charcoal in the rooting expression medium improved the overall rooting capacity of the mature explants to an average of 78%. Whatever the plant material, the number and the length of the adventitious roots, as well as the root score, fluctuated according to the sampling date.Abbreviations BA 6-benzyladenine - NAA naphthaleneacetic acid - REM rooting expression medium - RIM rooting induction medium     

长叶皇冠的组织培养与快速繁殖技术研究

以长叶皇冠短缩茎为外植体进行离体培养,对外植体灭菌方法以及培养基中不同种类和浓度生长调节剂对增殖、生根的影响等进行研究。结果表明:以0.1%的HgCl2为灭菌剂,采用8min+(6～8)min、间歇时间为24h的间歇灭菌法,可获得20%以上的成活无菌外植体;试管苗茎纵切成4份后,接种在1/2MS+6-BA6.0mg·L-1增殖培养基上培养42d,增殖系数可达9.3;在1/2MS+NAA0.2mg·L-1培养基上培养28d后,生根率达100%,平均每株约生根18条;炼苗后移植成活率100%。     

“艾西丝”南瓜诱导生根过程中过氧化物酶活性及同工酶的研究

以“艾西丝”南瓜组培苗为材料,研究其在诱导不定根形成过程中过氧化物酶活性及同工酶谱的变化。结果表明,当南瓜无根苗从含有较高浓度的ＢＡ培养基转入１／２ＭＳ培养基后,可诱导无根苗茎基部不定根生成,一般在转入生根培养基第３ｄ开始生根,至第６ｄ生根率达７０％以上。在此期间,南瓜茎内过氧化物酶活性由低增高,即在不定根形成之前,过氧化物酶活性处在较低水平,而当不定根形成时,过氧化物酶活性迅速升高,以后一直维持     

Adventitious rooting of Jatropha curcas L. is stimulated by phloroglucinol and by red LED light

An efficient root induction system has been established for in vitro-regenerated Jatropha curcas L. shoots. Callus formation on shoots transferred to auxin containing medium was found to be a prominent and recurrent problem for rooting of in vitro-cultivated J. curcas. In particular, the type of auxins and cytokinins applied in the culture media were shown to strongly influence the severity of callus formation. Shoots cultivated on meta-methoxytopolin riboside (MemTR) were free of callus and produced elongated stems and well-developed leaves in comparison to the cytokinins benzyl adenine, zeatin, and thidiazuron. Subsequent root induction experiments were performed with shoots precultured on MemTR-containing medium. Shoots were excised and transferred to Murashige and Skoog (MS) medium supplemented with different concentrations of indole-3-butyric acid (IBA), indole-3-acetic acid (IAA), and α-naphtaleneacetic acid (NAA). The induction of excessive callus formation was avoided only on IBA-containing medium. The optimum rooting medium with good root induction (35%) and 1.2 roots per shoot contained half-strength MS salts supplemented with 2.5 μM IBA. The same medium supplemented with 0.25% (w/v) activated charcoal produced 46% rooted shoots. Further improvement of rooting was obtained by transferring in vitro grown shoots to woody plant medium containing phloroglucinol (PG). In the presence of 2.5 μM IBA and 238 μM PG, 83% of the shoots rooted with on average 3.1 roots per shoot. We also analyzed the impact of light quality on the rooting capacity of Jatropha in vitro grown shoots. In general, light-emitting diodes (LEDs) light sources were less efficient for root induction. Red LED light provided the most favorable growth conditions, inducing a rooting response in 65% of the shoots, which produced on average 5.5 roots per shoot. These results indicate that adventitious rooting in J. curcas is under control of photoreceptors and that optimal rooting requires fine-tuning of the salt concentration, auxin, and cytokinin balance and application of synergistic compounds.     

Rooting and acclimatization of micropropagated cuttings of Pinus pinaster and Pinus sylvestris are enhanced by the ectomycorrhizal fungus Hebeloma cylindrosporum

The effect of different strains of the ectomycorrhizal fungus Hebeloma cylindrosporum on rooting in vitro and acclimatization of micropropagated cuttings of Pinus pinaster and Pinus sylvestris was studied. Two clones of P. pinaster and one of P. sylvestris were unable to root in the absence of auxin, but were induced to root on a medium devoid of auxin by all the fungal strains. Wild-type and indoleacetic acid (IAA)-overproducing mutant strains of the fungus stimulated rooting of clones showing a good reactivity to auxin to the same extent. In contrast, with a clone of P. sylvestris that showed low reactivity to auxin, IAA-overproduction by the fungus was advantageous for the induction of rooting of cuttings. Adventitious roots formed in the presence of a fungal strain were completely surrounded by a loosely packed network of hyphae which formed mycorrhizas as soon as roots grew outside the agar medium. During acclimatization, fungal inoculation improved the survival of rooted cuttings. At the end of acclimatization, fungal mycelia could be easily detected in the culture substrate of cuttings inoculated with dikaryotic strains and most of the pines' short roots were mycorrhizal. Monokaryotic mycelia, which have a lower growth rate and a lower infectivity, displayed poor ability to colonize the substrate and to form mycorrhizas. Two months after the end of acclimatization, fungal inoculation frequently depressed the growth of acclimatized cuttings of the clone J of P. pinaster . No depressive effect was observed with clone 78 and growth stimulation could even be observed with the infective dikaryon D1 which formed numerous mycorrhizas. From these studies, it was concluded that ectomycorrhizal fungi could be a suitable tool for improving rooting in vitro and survival at acclimatization of micropropagated conifer cuttings.     

Role of carbohydrates in micropropagation of cork oak

The influences of carbon sources, fructose, glucose, sorbitol and sucrose on shoot proliferation and in vitro rooting of cork oak (Quercus suber L.) were compared at a wide range of concentrations (1–6%, w/v). The highest number of shoots occurred on glucose-containing medium. Nevertheless, we have chosen 3% sucrose which induced a similar rate of proliferation but favoured shoot elongation, permitting an effectively higher number of shoots during transfers. Sorbitol and autoclaved fructose did not stimulate shoot proliferation. Adventitious root formation was strongly dependent on carbohydrate supply. Sorbitol and autoclaved fructose were completely ineffectively on rooting induction. Glucose was the most effective carbon source on rooting promotion followed by sucrose and filter-sterilized fructose. The rooting response induced by fructose was dependent on the sterilizing procedure. The number of adventitious roots produced per shoot increased with increasing glucose and sucrose concentration. The content of reducing sugars in leaves of proliferation cultures and in leaves and roots of rooted plantlets was more dependent on carbon concentration than on glucose or sucrose supplement. The results presented here show that carbohydrate requirements during cork oak micropropagation depend upon the phase of culture. Sucrose (3%) and glucose (4%) were the best carbon sources respectively during proliferation and rooting phases.     

Effect of Glucose and Auxins in Rooting Etiolated Stem Segments of Populus nigra

2.5 cm long stem segments of Populus nigra L. did not root when cultured in water or in auxins alone but rooted in glucose. The number of rooted segments and roots produced on them increased with rising glucose concentrations up to 0.5%, but decreased with higher concentrations. An addition of 1.0 mg/1 IAA inhibited rooting at 0.01 % glucose, was ineffective at 0.1 % and stimulative at higher concentrations of glucose which were inhibitory when used alone. The results show that the auxin effects on rooting are influenced by the nutritional status of the stem cutting of a species, and that a proper balance of the two is necessary for root development.     

Rooting of blue honeysuckle microshoots

Rooting of axillary shoots of two blue honeysuckle forms, Lonicera caerulea f. caerulea and L. caerulea f. edulis, was studied. Both in vitro and ex vitro rooting procedures were used, and the effects of mineral and auxin concentrations of the rooting media were tested. Reduced mineral nutrient concentrations of modified MS medium allowed more root elongation but did not affect the primary root number. The rooting percentage was high (≥ 90) in the form caerulea microcuttings but low (< 40) in the form edulis microcuttings when not treated with auxin. The rooting frequency and primary root number of the form edulis shoots could be increased up to 100 with 10 roots per microcutting, in the continuous presence of auxin. The continuous auxin treatments repressed the elongation and increased the diameter of primary roots and induced callus formation at the base of the shoots. Differences in root systems were related to equimolar concentrations of the auxins indole-3-butyric acid, indole-3-acetic acid and α-naphthaleneacetic acid, but the differences were diminished after one month ex vitro. After transfer ex vitro, several of the roots formed in vitro and some microcuttings died. A high rooting percentage and a good ex vitro survival and root growth of the form edulis microplants were achieved by a 7-day pulse with 4 μM indole-3-butyric acid followed by rooting ex vitro. This revised version was published online in June 2006 with corrections to the Cover Date.     

石龙尾(Limnophila sessiliflora BI.)的组织培养与快速繁殖技术研究

以石龙尾(Limnophila sessiliflora BI.)沉水枝带节茎段为外植体进行离体培养,研究外植体灭菌方法以及培养基中不同生长调节剂的浓度对其增殖、生根的影响。结果表明:以0.1%的HgCl2为灭菌剂,采用4 min+4 min、间歇4 h的间歇灭菌法,可以获得成活的无菌外植体15%;在1/2 MS+6-BA 2.0 mg·L^-1+NAA 0.1~0.2 mg·L^-1的增殖培养基上培养35 d,试管苗的增殖系数可达30.8以上;在1/2 MS+6-BA 0.3 mg·L^-1+NAA0.5 mg·L^-1的生根培养基上培养28 d后,可获得具3~5个侧枝的生根苗,平均每株生根数4.8条;炼苗后移植成活率100%。     

Micropropagation of <Emphasis Type="Italic">Theobroma cacao</Emphasis> L. using somatic embryo-derived plants

Summary A micropropagation protocol was developed using cacao somatic embryo-derived plant as a source for nodal and apical stem explants, and apical microcuttings. Microcuttings were efficiently rooted and developed into plantlets. Axillary meristems within the remaining decapitated plantlets subsequently developed and were used for production of additional microcuttings, with an average 2.4 growing shoots per decapitated stem. The remaining plantelts were maintained as microcutting stock plants. When nodal stem explants were cultured on thidiazuron medium, axillary buds proliferated and developed into shoots, which were excised and rooted. However, the efficiency of this method is lower than rooting of apical microcuttings harvested directly from stock plants. During root induction, short treatment with indole-3-butyric acid (IBA) increased the total percentage of rooted microcuttings up to 89%. Longer exposures to IBA increased the average number of roots per microcutting (from 1.7 to 5.2). Plant acclimatization after rooting was achieved with an average success of 87%. During several months of growth in the greenhouse, the micropropagated plants developed functional taproots. Currently, cocoa plants produced by this micropropagation method have been successfully acclimated to field conditions in Ivory Coast, Ghana, and Saint Lucia.