Adventitious Root Initiation In Reciprocally Grafted Leaf Cuttings from the Juvenile and Mature Phase of Hedera helix L

Reciprocal grafts involving leaf petioles and lamina of thejuvenile and mature phase of Hedera helix were prepared to determinethe relative importance of petiole and lamina on root initiationin leaf cuttings. The results indicated that root initiationwas mainly a function of the potential of cells in the petioleto respond in a specific morphogenetic pattern. Initially, rootinitiation was unaffected by the type of lamina. However, overtime, a factor translocated from the juvenile lamina promotedroot initiation in the mature petiole. This factor decreasedthe time taken for root initiation and increased the numberof roots per mature petiole. There was no evidence for an inhibitorfrom the mature lamina affecting root initiation in the juvenilepetiole. Key words: Rejuvenation, root initiation, rooting cofactors     

Role of Auxin and Polyamines in Adventitious Root Formation in Relation to Changes in Compounds Involved in Rooting

   apd: 3 July 2001     

Ribosomal RNA Gene Redundancy in Juvenile and Mature Ivy (Hedera helix)

Two-fold variation was found in rRNA gene redundancy in differentpopulations of ivy (Hedera helix). No consistent differencein rRNA gene number was observed between the juvenile and matureforms of the plant. Small significant differences between therRNA gene content of mature and juvenile forms and also betweenundeveloped buds and expanded leaves were found but these werein different directions in different populations.     

Adventitious Root Formation in Veronica Spp.

Species of the genus Veronica differ in habitat preferences,growth form and in adventitious root production. The annualspecies rarely or never produce adventitious roots in intactplants in the field but some, for example V. persica and V.arvensis will root vigorously from single node stem segmentsin culture. Others, such as V. agrestis require the presenceof IAA for substantial levels of root formation to occur incultured stem segments. Veronica hederifolia cuttings rarelyproduce roots. Stem cuttings of the perennial species, in general,rooted more vigorously than those of annual plants. Both V.fihiformis and V. serpyllifolia root very strongly. The position of root production from the stem cuttings differedfrom species to species. Roots arose either from the node, theregion of the base or at some intermediate point. Veronica arvensis,V. chamaedrys and V. persica rooted mainly from the basal regionwhereas V. filiformis rooted mainly from the node. Veronicaserpyllifolia cuttings rooted at both of these locations. Veronica filiformis, a perennial species that is infertile inBritain, produces root primordia in intact plants at nodes whichare close to the shoot apex. Thus, even very young stem segmentshave ‘preformed’ root primordia. For this reason,detached stem segments of V. filiformis root very rapidly andthis probably has been of great significance in its successfulinvasion and spread in lawns and short turf areas. Veronica spp., adventitious roots, indol-3-ylacetic acid, root primordia, vegetative reproduction     

Morphactin and Adventitious Root Formation in Pea Cuttings

Stock plants of pea (Pisum sativum L. cv. Alaska) were grown at different controlled levels of irradiance (4, 16 or 38 W m^?2) for 11 days from sowing. Morphactin (CFM, methyl-2-chloro-9-hydroxy-fluorene-9-carboxylate) was applied to the apex of the stock plants 3 days before cuttings were excised. The cuttings were rooted at 16 W m^?2. High levels of morphactin (>5 × 10^?3 mg l^?1) inhibited root formation in the cuttings. Low concentrations of CFM (5 × 10^?5 mg l^?1) promoted the formation of adventitious roots in cuttings from plants grown at all three levels of irradiance, with the most pronounced effect in cuttings from 4 W m^?2. Measurements of ethylene evolution by CFM-treated plants 3 days after application, revealed a stimulatory effect on ethylene production by high CFM concentrations.     

Involvement of Polyamines with Adventitious Root Development in Stem Cuttings of Mung Bean

Spermine enhances the number of adventitious roots developingon stem cuttings of Phaseolus aureus Roxb. This effect is observedwhen spermine is supplied alone to cuttings or in the presenceof indolebutyric acid (IBA). That concentration most effectivein inducing the rooting response also enhances root growth.Other concentrations tested were without effect on growth. Spermidinedoes not influence root number or growth except at high concentration,when it is inhibitory to number only. Methylglyoxal bis(guanylhydrazone)(MGBG) inhibits rooting and root growth in the presence or absenceof IBA. Treatment of stem-cuttings with IBA leads to enhancedlevels of spermine, spermidine and putrescine in the hypocotylprior to development of any root primordia. MGBG reduces thelevels of spermine and spermidine whilst increasing the levelof putrescine. Furthermore, MGBG prevents the IBA-induced increasein spermine and markedly inhibits that in spermidine. Theseresults are consistent with an essential role for polyaminesand their metabolism in the early events which lead to adventitiousroot development. (Received January 10, 1983; Accepted March 17, 1983)     

Steroidal Oestrogens and Adventitious Root Formation in Phaseolus Cuttings

Solutions of oestrone, oestrone-phosphate, oestrone-sulphate,oestradiol and oestradiol-sulphate in the concentration range10^–3 mol m^–3 to 10^–7 mol m^–3 had noobservable morphological or anatomical effects on adventitiousroot formation in Phaseolus vulgaris hypocotyl, epicotyl andprimary leaf cuttings. Oestradiol-sulphate and oestrone-sulphatetreatments at 0.1 mol m^–3 significantly inhibited rootingin hypocotyls, and the inhibition was almost complete in epicotylsand primary leaves. In the latter, anomalous development ofvascular tissues was noted. However, neither oestrone-phosphateat 0.1 mol m^–3 nor direct application of up to 100 µgof the oestrogens to apices or primary leaves of explants modifiedthe pattern of root formation. The results are discussed withreference to the distributive and metabolic fates of the appliedsubstances. Phaseolus vulgaris L., bean, adventitious roots, steroidal oestrogens, translocation     

不定根形成与植物激素的关系

不定根形成的关键是其原基的形成,是一个受激素调控的复杂过程,生长素起关键的调节作用.该文介绍生长素、乙烯、细胞分裂素、赤霉素、脱落酸和其它植物生长调节物质在不定根形成中的作用,并讨论了它们之间的相互关系.     

Adventitious Root Formation in Young Shoots of Cedrus Deodara

The effect of auxins [indole-3-butyric acid (IBA) and -naphthaleneacetic acid (NAA)], phenolics (phloroglucinol and coumarin), a combination of auxins and phenolics, and a systemic fungicide (Bavistin, containing 50% carbendazim) on adventitious root formation in stem cuttings (current season's growth) of Cedrus deodara L. during winter and monsoon (rainy) seasons has been examined. Significant stimulation of rooting due to treatments was observed in cuttings planted in winter in the following order: 0.25 mM IBA (87.5% rooting) > 5 mM coumarin (70.8%) > IBA (0.5 mM) + coumarin (5 mM) (50.0%). In cuttings planted in monsoon only 0.05% Bavistin was found to be effective in inducing rooting (83.3%). Other treatments were ineffective and in some treatments drying of cuttings was noticed.     

Polyamines and Root Formation in Mung Bean Hypocotyl Cuttings : II. Incorporation of Precursors into Polyamines

The incorporation of [¹⁴C]arginine and [¹⁴C]ornithine into various polyamines was studied in mung bean (Vigna radiata [L.] Wilczek) hypocotyl cuttings with respect to the effect of indole-3-butyric acid on adventitious root formation.

Both [¹⁴C]arginine and [¹⁴C]ornithine are rapidly incorporated into putrescine, spermidine, and spermine, with similar kinetics, during 5- to 24-hour incubation periods. The incorporation of arginine into putrescine is generally higher than that of ornithine. The biosynthesis of putrescine and spermidine from the precursors, in the hypocotyls, is closely related to the pattern of root formation: a first peak at 0 to 24 hours corresponding to the period of root primordia development, and a second peak of putrescine biosynthesis at 48 to 72 hours corresponding to root growth and elongation. Indole-3-butyric acid considerably enhances putrescine biosynthesis in both phases, resulting in an increase of the putrescine/spermidine ratio.

It is concluded that the promotive effect of indole-3-butyric acid on putrescine biosynthesis, from both arginine and ornithine, supports the hypothesis that auxin-induced root formation may require the promotion of polyamine biosynthesis.

     

iTRAQ Protein Profiling of Adventitious Root Formation in Mulberry Hardwood Cuttings

The ability to form mature adventitious roots (AR) provides a competitive advantage for clonal multiplication of elite genotypic plant species, because high economic losses occur as a result of insufficient rooting. To better understand potential mechanisms involved in AR formation, we utilized an iTRAQ-based proteomic approach on mulberry hardwood cuttings. A total of 4427 proteins were identified from the base of cuttings, of which 595 and 231 proteins showed differential accumulations in the two periods of rooting, respectively. Three differentially expressed enzyme proteins were validated by an enzyme assay and qPCR. Functional annotation analysis showed that dysregulated proteins were involved in glucose metabolism, flavonoids biosynthesis, cell wall modification, and hormone regulation, indicating potential contributions to adventitious rooting. These results provide fundamental and important information for research on the molecular mechanism of AR development in mulberry cuttings and facilitate rooting efficiency in agricultural practice.     

芒果子叶切段不定根形成的影响因素分析

分别用不同成熟时间、不同取材部位、不同品种、不同大小的芒果子叶切段为外植体进行不定根的诱导,以探讨影响芒果子叶切段不定根形成能力的原因.结果表明,芒果子叶切段的生根能力随着芒果成熟度的增加而逐渐提高,花后50和60 d的2.0 cm长子叶切段都无不定根形成,从花后70 d开始有不定根形成,此时生根率为28.6%,之后其生根能力迅速提高,在花后90 d生根率达到76.7%,之后生根率稳定保持直到110 d果实成熟.成熟芒果的子叶切段长度(2.0、1.0、0.5和0.2 cm)对不定根的形成有显著影响,0.2 cm的子叶切段上无不定根形成,另外3个长度的切段都有不定根形成,且生根能力随着长度的增大而逐渐提高.取材位置(靠近或远离胚轴)则对生根影响不大,且紫花芒、红芒、青皮芒等几种常见芒果品种的不定根形成能力基本相同.     

A Relationship between Length of Basis and Adventitious Root Formation in Pea Cuttings

A positive correlation between the length of the basis and the ability of the cuttings to form adventitious roots was observed in pea cuttings. Plants with a different basis length (the third internode) were obtained in different ways: Regulation by the level of irradiance, dark treatment or gibberellic acid. The length of the basis was also regulated by excision of the cuttings at different places on the stock plants. With increasing basis length an increase was found in the number of roots subsequently formed. The results were similar in cuttings from plants grown at different levels of irradiance or from dark treated plants. Optimal rooting was obtained by cutting the plants just above the second scale leaf. Cuttings from plants treated with 10^?3M GA₃ showed the same correlation between the length of the third internode and root formation as found in the other experiments, but the number of roots were at a lower level.     

黄瓜和绿豆下胚轴不定根发生的研究

在MS基本培养基上,黄瓜和绿豆幼苗的下胚轴切段培养4d时即可见不定根发生。下胚轴不同部位切段的发根能力不同。下胚轴切段反插时比正插时发根快1-2d,发根率也高于正插的;0.01-0.05mg/L的NAA还诱导下胚轴切段在形态学上端发根。TIBA对正插或反插的下胚轴切段的不定根发生都有抑制作用。结果提示,生长素极性运输活性对不定根形成起着重要作用。     

Protein Changes Associated with Adventitious Root Formation in Hypocotyls of Pinus Radiata

The changes in soluble proteins associated with adventitious root formation in hypocotyls of radiata pine (Pinus radiata D. Don) were studied using one- and two-dimensional polyacrylamide gel electrophoresis. Protein content decreased during the first day after root excision, and kept decreasing till the end of the time course under non-rooting conditions, i.e., on medium without growth regulators, with indole-3-butyric acid (IBA) + kinetin, or with kinetic alone. During adventitious root initiation in response to IBA, however, the protein content began to increase from day 1 to its maximum at day 7, coinciding with the early stage of root initiation. A comparative analysis of protein changes by two-dimensional polyacrylamide gel electrophoresis showed 16 proteins that were probably associated with root initiation and development.     

Silencing of the MADS-Box Gene SlMADS83 Enhances Adventitious Root Formation in Tomato Plants

Journal of Plant Growth Regulation - Adventitious roots (ARs) are important for the growth of plants and the improvement in their stress resistance and survival capacity. Although many genes have...