Juvenility and endogenous rooting substances inCastanea sativa Mill

The rooting response to exogenous auxin of cuttings in a juvenile phase of growth from plants ofCastanea sativa Mill. was determined and simultaneously the rooting potential of the water extracts was evaluated in presence of IAA by a bean rooting test. The level of the extractable rooting promoters was high in the cuttings which exhibited the highest percentage of rooting. An inhibition of the effect of IAA on rooting was detected in the cuttings which showed the lowest rooting response, the histogram differing not much from that of the adult plant. The results indicate that in chestnut the juvenile condition, easy rooting, is associated with high levels of endogenous rooting promoters.     

Root-promoting Substances in Salix alba

Root-promoting substances were extracted from softwood cuttings of Salix alba L. by centrifuging them with water or by shaking the ground freeze-dried stems with water. Rooting substances were partitioned by paper chromatography or chemical fractionation and their rooting activity was tested by mung bean cuttings. Both extracts indicated three major root -promoting fractions at Rf 0-0.1, 0.7-0.8, and 0.3-0.4 in a decreasing order of their activities when paper chromatographed with isopropanol:ammonia:water 8:1:1 v/v. The strongest one indicated an apparent synergistic rooting effect with indol-3yl-acetic acid (IAA) regardless of the extraction method. These results indicate that water can extract from freeze -dried sample the similar rooting substances found in the centrifugal diffusates. The Rf 0–0.1 fraction consisted of at least four fractions and the strongest one did not move from the starting line on the chromatogram when isopropanol:ammonia:water 8:1:1 was used. This starting line fraction was extremely strong in rooting activity and its highest concentration resulted in 8.7 times as many roots as controls. More thain additive rooting effect between IAA and the fraction was found only at the highest concentration. The fraction was very soluble in water but insoluble in chloroform or ethyl ether and only stimulated rooting of mung bean cuttings when it was applied within 3 days after cuttings were made. It had no effect in lengthening roots. The starting line fraction was further found to have four root-promoting subfractions at Rf 0.05, 0.35, 0.65, and 0.85 when it was chromatographed in 60 % isopropanol. Among these four, the subfractions at Rf 0.65 and 0.35 were strongly root promotive and displayed more than additive root promotion with IAA at the highest concentrations studied.     

Effect of abscisic acid on endogenous IAA, auxin protector levels and peroxidase activity during adventitious root initiation in Vigna radiata cuttings

Endogenous levels of free and conjugated IAA, auxin protectors (Prs) and peroxidase (PER) activity and their relation to adventitious root initiation (ARI) were investigated at the potential sites of adventitious rooting in relation to exogenous application of 250 μM ABA during the first 120 h after treatment. Cuttings from 7-day-old mung bean [Vigna radiata (L.) Wilcz.] seedlings were treated with 125, 250, and 500 μM ABA for 24 h. ABA significantly stimulated ARI but extremely inhibited epicotyl growth as compared to control. Free and conjugated IAA were measured by reversed-phase high performance liquid chromatography while Prs and PER activities were measured spectrophotometrically. The present results also indicate that endogenous free IAA levels peaked later in ABA-treated cuttings than that in control, suggesting that ABA extended the length of the induction phase of rooting process in treated cuttings and that might explain the significant delay of the appearance of roots at the treated cuttings. Higher level of IAA conjugates was found in ABA-treated cuttings than that in untreated ones. Pr level also peaked later in ABA-treated cuttings than that in control, indicating that ABA extended the period of Pr activity. An initial temporary decrease of PER activity was found in associating with high levels of free IAA and Prs during most of the primary events, while the opposite occurred during the secondary events of adventitious rooting process in both treated and untreated cuttings. Thus, ABA may stimulate ARI in mung bean Vigna radiata cuttings by regulating the concentration and /or activities of endogenous IAA, Prs, and PER activity in favor of inducing a large number of adventitious roots at their potential sites of adventitious rooting.     

沙生柽柳扦插生根过程插穗相关理化特征分析

选取沙生柽柳半木质化枝条进行苗床扦插,通过实验测定插穗生根过程中内源激素(IAA、GA3、ZR、ABA)含量、可溶性营养物质(糖、蛋白质)含量及相关氧化酶(PPO、POD、SOD、IAAO)活性的动态变化特征,探讨沙生柽柳插穗扦插生根机理。结果表明:(1)沙生柽柳插穗内源激素含量随生根进程而发生变化,其中,IAA含量在扦插35d最大,并出现较大的波动变化;ZR含量在扦插55d前后变化明显,呈现低水平向高水平转化趋势;ABA、GA3含量依次呈先升高后降低再升高的变化过程,并在扦插15d和55d(80d)呈现变化的峰值和谷值。(2)沙生柽柳扦插生根与相关氧化酶活性密切相关,其中,POD、IAAO活性在插穗扦插35d后长时间保持较高水平,直至插穗生根后POD活性明显降低,IAAO活性有所增加;PPO、SOD活性则在插穗扦插15d保持较高活性,且PPO活性的变化均匀,SOD活性的高低交替变化明显。(3)在沙生柽柳扦插生根期间,插穗可溶性糖含量呈现生根前消耗减少与生根后积累增加两大变化过程,可溶性蛋白质含量表现为扦插后逐步积累增加的变化趋势。研究表明,高水平的IAA、ZR和低水平的GA3、ABA共同调控着沙生柽柳插穗生根;IAA能够通过促进插穗POD、PPO、IAAO活性变化来影响生根,较高的POD、IAAO活性可调节插穗IAA水平,高水平的PPO活性则催化插穗IAA-酚酸复合物的形成,进而诱导插穗生根。     

Treatment of bean cuttings by chestnut extracts during rooting modifies their IAA-oxidase activity

The IAA-oxidase activity in bean cuttings ( Phaseolus vulgaris L. cv. Contender) treated with extracts from juvenile and adult chestnut ( Castanea sativa Mill.) was studied in the light of the effect of the extracts on the rooting activity of some auxins. Extracts from adult chestnut increased IAA-oxidase activity in bean cuttings. Extracts from juvenile chestnut inhibited IAA-oxidase activity only slightly, but substantially reduced the IAA-oxidase activity of bean cuttings pre-treated with adult chestnut extracts. These findings provide evidence that there is a relationship between the IAA-oxidase system and the effect of chestnut extracts on IAA-induced rhizogenesis in bean cuttings.     

The effect of indole-3-acetylaspartic acid on adventitious root formation on bean cuttings

The influence of indole-3-acetylaspartic acid (IAAsp) on rooting of stem cuttings from bean plants (Phaseolus vulgaris L.) of different ages, cultivated at different temperatures (17°, 21° and 25°C) was studied and compared to that of indole-3-acetic acid (IAA). At a concentration of 10^–4 M, IAAsp only nonsignificantly stimulated adventitious root formation, approximately to the same level as IAA in all treatments. IAAsp at 5×10^–4 M further enhanced rooting, by up 200% of control values, with little influence of temperature conditions and stock plant age. This concentration of IAA usually stimulated rooting more than the conjugate. The largest differences between the effects of IAAsp and IAA occured at the highest cultivation temperature of 25°C where stock plant age also influenced the response. The number of roots produced in comparison with the control, was enhanced from 350% on cuttings from the youngest plants to more than 600% on cuttings from the oldest. In contrast to the conjugate, 5×10^–4 M IAA induced hypocotyl swelling and injury of the epidermis at the base of cuttings, in all treatments.     

Effect of Auxins on Adventitious Root Development from Single Node Cuttings of Camellia sinensis (L.) Kuntze and Associated Biochemical Changes

An attempt was made to induce rooting from single node cuttings of Camellia sinensis var. TV-20 under controlled conditions and study its biochemical changes during rooting. The nodal cuttings were pretreated with different concentrations of IAA, NAA and IBA and kept in a growth chamber (25 ±2 °C, 16 h photoperiod (55 μ mol m⁻² s⁻¹) with cool, white fluorescent lamps and 65% relative humidity) for 12 h. Among the three auxins used for pretreatment, IBA showed more positive response on rooting as compared to IAA and NAA within 2 weeks of transfer to potting medium. Among four concentrations of IBA tested, 75 ppm gave maximum percentage of rooting, number of roots and root length. Therefore, IBA was used further in experiments for biochemical investigation. The adventitious rooting was obtained in three distinct phases i.e. induction (0–12 days), initiation (12–14 days) and expression (14–18 days). IAA-oxidase activity of IBA-treated cuttings increased slightly as compared to control. The activity was found to decrease during induction and initiation phases and increase during expression phase. The peroxidase activity in IBA-treated cuttings increased up to initiation phase and declined at the expression phase. Polyphenoloxidase activity increased both in IBA-treated and control cuttings during induction and initiation phase but declined slowly during expression phase. Total phenolic content was higher in IBA-treated cuttings, particularly in initiation and expression phases and it also correlated with peroxidase activity. Phenolics might be playing key role for induction of adventitious rooting, and phenolic compounds can be used as rooting enhancer in tea plant.     

NAA处理对艾纳香扦插生根生理生化特性的影响

为探讨NAA对艾纳香(Blumea balsamifera)扦插生根的影响,4 a生艾纳香健康枝条用500 mg/L NAA处理,对生根过程中的生理生化特征进行了研究.结果表明,艾纳香扦插生根率与内源IAA、GA含量和IAA/ABA呈正相关,而与ABA含量呈负相关.NAA处理能提高插穗的IAA含量,降低ABA含量,有助...     

Promotion of adventitious root formation by 4-chlororesorcinol: A polyphenol oxidase inhibitor

The extent of rooting in cuttings of Phaseolus vulgaris L., and Vigna radiata Wilcz. was affected by 4-chlororesorcinol, a polyphenol oxidase inhibitor. More root primordia and more roots were formed after 4-chlororesorcinol treatment both with and without 10^-5M Indole butyric acid. Promotion of rooting was observed also in cuttings of Elaeagnus pungens, Gypsophilia elegans and Kalanchoe blossfeldiana. The enhancement in bean and mung bean was accompanied by a concomitant wider spatial distribution of the primordia and the resulting adventitious roots. The formation of primordia in the treated cuttings was delayed by 12–24 hours, compared to untreated cuttings. The treatment was effective only when given during the first hours after the preparation of the cutting of bean and mung bean, suggesting involvement in the initiation stage. Hypocotyl extracts of mung bean cuttings, pretreated with 4-chlororesorcinol, exhibited reduced polyphenol oxidase activity. The inhibition was not reversed by washing of the treated extract in 50% acetone or by an overnight dialysis, suggesting tight or maybe even irreversible binding of the inhibitor to the enzyme.Abbreviations 4-CR 4-chlororesorcinol - IBA Indole butyric acid - PPO polyphenol oxidase     

The effect of cold storage at 4 °C on the Rooting of chestnut cuttings

This article reports the effect of cold storage at 4 °C from December to April on chestnut cuttings. Rooting was found to increase after four months preceded by treatment with 4000 mg l^-1 IBA. ThePhaseolus test of the biological activity of extracts of the cuttings showed the inhibition exerted by the acid fraction of the fresh (December) cuttings to have been replaced by a rootpromoting effect in cuttings stored for 4 months at low temperature. Cold storage thus seems to favour rooting.     

木质素含量对四倍体刺槐嫩枝插穗扦插生根的影响

以四倍体刺槐1年生嫩枝插条为试验材料,分析插穗木质素含量与其横截面剪切强度、相关酶活性和激素关系,并探究不同木质素含量的插穗扦插生根性状的效应,为四倍体刺槐扦插选择合适插穗提供理论参考。结果表明:(1)插穗的木质素含量与其横截面剪切强度呈极显著正相关关系(相关系数为0.99),根据剪切强度可以间接地估算其木质素含量。(2)插穗的木质素含量与其POD和PPO活性呈极显著正相关关系(POD相关系数为0.98,PPO相关系数为0.92),也与激素ABA含量呈极显著的正相关关系(相关系数为0.97),而同IAA、IBA呈不显著的相关性,根据POD和PPO活性以及激素ABA含量对生根的影响可以推测木质素含量对生根有一定的影响。(3)不同木质素含量的插穗生根性状差异显著,木质素含量为19.47%时插穗生根能力最强,其插穗生根率为60.39%,平均每株生根量为9.70个,根长为4.85cm;木质素含量为10.60%时插穗生根能力最差。(4)生根性状最佳时的木质素含量为19.47%,其对应的剪切强度范围为40～50kg。     

Light effects on root formation in aspen and willow cuttings

The effect of light on rooting of leafy cuttings of aspen (Populus tremula × tremuloides) and a willow hybrid (Salix caprea × viminalis) was investigated under controlled conditions in water culture. Two levels of irradiance were used, 40 and 8 W m^?2. The lower level gave the best rooting of aspen cuttings, both when applied to the stock plants before the cuttings were taken and when given to the cuttings during the rooting period. Irradiation of the cutting base during the rooting period inhibited rooting almost completely in aspen and decreased the number of roots formed in the Salix hybrid. Net photosynthesis in the cuttings of Salix decreased considerably after excision and increased again after formation of roots. Indirect evidence indicated that photosynthesis was even more affected in aspen cuttings. The possible roles of carbohydrates and inhibitors in the light effects are discussed.     

Adventitious rooting: examining the role of auxin in an easy- and a difficult-to-root plant

Therooting responses of cuttings of difficult-to-root lilac (Syringavulgaris) and easy-to-root forsythia(Forsythia×intermedia)were compared. The rooting ability of lilac cuttings declined over the growingseason (May–June). There was also a decline in the initial concentrationof free IAA at the base of the cuttings, but there was not a tight relationshipbetween basal IAA concentration and rooting ability. Polar auxin transportability was measured in lilac and forsythia during the period of maximum growthby [³H]IAA application to stem internodal tissue. Transport abilitydeclined in lilac over this time period, particularly in terms of transportintensity and percentage of [³H]IAA transported. In contrast thechanges in polar auxin transport ability in forsythia were less marked. Thisdifference between species was maintained in winter hardwood cuttings, withforsythia tissue showing greater polar auxin transport ability than lilac. Theimportance of polar auxin transport for adventitious rooting was demonstratedinboth lilac and forsythia softwood cuttings by use of the polar transportinhibitor 2,3,5-triiodobenzoic acid (TIBA). Overall the results indicate thatdifferences in polar auxin transport ability between lilac and forsythiacontribute to differences in rooting ability.     

Changes in the rooting inhibitory effect of chestnut extracts during cold storage of the cuttings

Extracts of cold stored chestnut cuttings ( Castanea sativa Mill.) were examined for the inhibitory effect on the stimulation of rooting by 1AA which has been detected previously in extracts from freshly collected cuttings. The extracts were fractionated by paper chromatography and the different zones of the chromatograms were bioassayed together with 1AA by the bean rooting test. The bean rooting test showed that the inhibitory effect decreased with the length of cold storage period, so that after 5 months of storage, the inhibitory effect had disappeared, and a root promoting zone was found on the chromatograms. A comparative study of phenolics in this zone, before and after cold storage, revealed the formation of vanillyl and salicyl alcohols in the chilled material. Vanillyl and salicyl alcohols are rooting stimulators and increase the effect of 1AA on rooting in bean cuttings.     

Stimulation of adventitious root formation in non-woody stem cuttings by uridine

Uridine strongly stimulated adventitious root formation in stem cuttings of sunflower (Helianthus annuus L.), mung bean (Vigna radiata L.) and common bean (Phaseolus vulgaris L.). A dose response curve of uridine induced rooting showed that the optimum concentration of uridine was 0.1 µM. At all concentrations employed, uridine had no significant effect on root elongation. The rooting response of stem cuttings to the optimal concentration of indole-3-butyric acid (10 µM) in combination with 0.1 µM uridine did not significantly differ from their response to either of these compounds when applied alone. However, the rooting response of the cuttings to sub-optimal IBA (0.01 µM) was significantly stimulated by uridine. These findings suggested that uridine may have stimulated rooting by increasing the sensitivity of the rooting tissue to auxin.     

Biosynthesis of plant hormones during anaerobic digestion of instant coffee waste

A large amount of solid waste remains after the production of instant coffee. This waste has to be moved to dumps, where it poses a threat of environmental pollution. Treatment of this waste by anaerobic methanogenic thermophilic digestion produced, besides biogas, a digested slurry which was used as a growth medium for horticulture, and proved to be a suitable and economical substitute for peat moss. Biological tests with mung bean cuttings and Grevillea plantlets showed promotional effects on rooting of the slurry and its sieved fraction extract, washed with water (Capul). Green coffee beans, instant coffee waste, its anaerobically-digested slurry and Capul were extracted by various methods and the extracts were analyzed by TLC, HPLC and GC/MS. Examinations showed clearly the presence of IAA and IBA in free and bound forms in all the substrates. The values of free and bound IAA were calculated by use of an internal standard and GC/MS. The amount of conjugated IAA was found to be much higher than that of free IAA, in both the coffee beans and instant coffee waste (11.1 vs 2.7 nmol g^–1, respectively). In the digested slurry and Capul, however, most of the IAA was present as the free form and was approximately 23.5–33.0 nmol g^–1, which is almost ten times more than in the waste, and almost twice the total amount of IAA in coffee beans. It is postulated that the high levels of free IAA in the digested instant coffee waste are a result of catabolism of tryptophan by anaerobic bacteria.     

Polar Transport of Indole-3-Acetic Acid in Relation to Rooting in Carnation Cuttings: Influence of Cold Storage Duration and Cultivar

The influence of cold storage of cuttings on the transport and metabolism of indole-3-acetic acid (IAA) and the rooting were studied in two carnation (Dianthus caryophyllus L.) cultivars (Oriana and Elsy), which are known to exhibit very distinct rooting characteristics. The percentage of rooting at 11 d after planting increased with the storage period particularly in Oriana, but the values in Elsy were higher than in Oriana. Auxin transport was measured by applying ³H-IAA to stem sections. Irrespective of the section localization, the oldest node (node) or the basal internode (base), the transport increased as the storage period increased from 2 to 12 weeks in Oriana and from 2 to 8 weeks in Elsy cuttings. The auxin transport rate was higher in bases than in nodes and also in Elsy than in Oriana at a given storage period. IAA oxidation and hydrolyzation of IAA conjugates (determined by extracting the sections with acetonitrile and NaOH once the basipetal IAA movement ceased after a 24 h transport period) showed a negative, highly significant correlation with the amount of IAA transported. Although the rooting percentage and IAA transport were higher in Elsy than in Oriana, the differences in rooting between the cultivars could not be explained solely by differences in IAA transport.     

Seasonal Rhythm of Rooting of Salix atrocinerea cuttings

The response of rooting and the content of growth substances in Salix atrocinerea cuttings were studied every month throughout the whole year. To study the rooting response 100 cuttings were put into a rooting mist-propagator frame and the results were observed 30 days later. The hormone content was studied with the same type of cuttings by means of methanol extraction, fractionating into acid, basic and neutral substances and chromatographic analysis on paper and bioassays. Salix atrocinerea cuttings have three rooting phases: one very active in January, February, March and April with plentiful roots, not ramified, originating at the base of the cutting; a second lesser phase from May to August with numerous small and very ramified roots formed at a more ample area on the stalk. Both peaks are separated by a sharp fall in June. From September to December the third phase of rooting takes place. Response is practically nil and the few small roots formed are originated at the base of the stalk, again, as in the first phase. In the histograms a remarkable activity in the acid fraction at Rf = 0.30–0.50 was found and IAA was identified. The rooting capacity of these cuttings and the IAA content show some correlation but not exact enough to assert that the root response is governed by an optimum hormonal content. In Salix atrocinerea cuttings inhibitors are absent during the whole year which support the hypothesis that root formation might in some cases be influenced also by the presence or absence of inhibitory growth substances.     

Influence of Aryl Esters of Indole-3-acetic and Indole-3-butyric Acids on Adventitious Root Primordium Initiation and Development

Synthetic aryl esters of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) greatly enhanced adventitious root primordium initiation in bean (Phaseolus vulgaris L. cv. Top Crop) and jack pine (Pinus banksiana Lamb.) cuttings, respectively. Bean cuttings produced 95 to 154% more macroscopically visible root primordia in 2 days when treated with phenyl indole-3-acetate (P-IAA), in comparison with an equal concentration of IAA. Substantial but lesser increases occurred when treatment was done with 3-hydroxyphenyl indole-3-acetate (3HP-IAA). On a molar basis, either P-IAA or 3HP-IAA were 10 or more times as efficient as IAA in inducing adventitious root primordium initiation in bean cuttings. Methyl indole-3-acetate was no more effective than IAA in these tests. Phenyl indole-3-butyrate (P-IBA) consistently enhanced the number of rooted jack pine seedling cuttings by 11 to 12% in comparison with a 27% higher concentration of IBA. The number of elongated roots (2 mm or more) after 5 days was 165 to 276% greater for P-IAA than for IAA-treated bean cuttings. Similar but lesser increases occurred as a result of 3HP-IAA treatment. P-IBA in comparison with IBA treatment did not influence either the number of roots or length of the longest root per rooted jack pine cutting. Enzymes in bean and jack pine cuttings hydrolyzed the aryl esters. However, check experiments showed that initial integrity of the esters was required for enhanced activity in inducing root primordium initiation. Treatment of bean cuttings with hydrolysates of P-IAA, or with IAA and phenol, alone or combined, did not influence root primordium initiation or development in a manner different from treatment with IAA alone.     

Conditions for rooting of leafy cuttings of Alnus incana

The rooting of softwood cuttings of Alnus incana (L.) Moench in nutrient solution was studied under controlled conditions. Cuttings consisting of one internode with the leaf and axillary bud attached rooted easily and more rapidly than shoot tip cuttings. Light was necessary for rooting but good rooting was obtained in photon flux densities of both 40 and 190 μmol m^-2s^-1. Root number and root length was reduced when light reached the base of the cuttings. Treatment with indolebutyric acid (10^-6–10^-4M) increased the number of roots but 10^-4M delayed rooting and decreased the root length. Debudded internode cuttings rooted as well as intact cuttings, and detached leaves also contained sufficient substances for rooting.