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1.
Micropropagated plantlets of OH x F 51 and GF 677, respectively pear (Pyrus communis L.) and peach (Prunus persica x Prunus amygdalus) clonal rootstocks were inoculated during an early weaning stage of acclimatization with Glomus sp. Both rootstocks were well colonized, although the infection of OH x F 51 spread more slowly. At the end of initial vegetative growth, mycorrhizal plants of both rootstocks showed a three-fold increase in shoot length over control plants. Mycorrhizal plants also had longer internode and greater fresh mass. The root/shoot ratio was especially altered by arbuscular mycorrhizal inoculation in OH x F 51 plants, which showed a greater increase in shoot rather than in root biomass. The growth-promoting ability of endomycorrhizal fungus persisted throughout the experimental period: Glomus sp. induced a greater development of both rootstocks in the second growing year, after overwintering. Colonization of micropropagated plants by arbuscular mycorrhizal fungus appears to alter the carbohydrate status in stems and roots. Mycorrhizal plants always had a higher content of total soluble sugar, although there were no differences in soluble carbohydrate concentration between inoculated and uninoculated plants. Starch accumulation was found only in mycorrhizal plants of the peach rootstock.  相似文献   

2.
Summary

Experiments were conducted to optimize nutritional and cultural requirements for initiation and growth of roots on papaya in vitro. Axillary shoots were obtained from plants which had been sub-cultured monthly for two years. Root initiation was enhanced when 1 to 2 mm of stem base was removed and shoots were growing actively before transfer to the rooting medium. Decreasing daylength during incubation from 24 h to 12 h promoted root initiation. Within the day temperature range of 22 to 29°C, optimum rooting occurred at 27°C and higher temperatures produced higher mean root weights per shoot. High concentrations of growth factors and the absence of sucrose in the medium both reduced root initiation, however, varying the concentration of sucrose and removing growth factors affected mean root weight per shoot. All media contained a modified de Fossard et al. (1974) basal medium plus 10 μM IBA.  相似文献   

3.
The effect of substrate, medium composition, irradiance and ventilation on rooting percentage, and root morphology and functioning with respect to mineral uptake was investigated in jojoba [Simmondsia chinensis (Link) Schneider]. Plantlets grown on Sorbarod plugs embedded in perlite accumulated more biomass and showed better rooting than plantlets grown on Sorbarod plugs embedded in agar. In plants grown on the latter substrate, the addition of sucrose to water or salts media promoted rooting and accumulation of shoot and root biomass. On perlite, rooting was high in all treatments, while root growth was enhanced only by 2% sucrose. Sucrose and irradiance had a positive synergistic effect on plantlet growth. Doubling the irradiance from 58 to 116 μE m−2 s−1 and using high ventilation (22-mm membrane) failed to improve rooting but promoted the ability of the stomata to close, thereby reducing water loss under ambient conditions. High irradiance and ventilation lowered the chlorophyll content, but without impairing biomass accumulation. Plantlets grown under enhanced ventilation and 0.5% sucrose formed fine roots within the cellulose plug and thick roots on the vessel floor. With the 2% sucrose supplementation, the roots were generally thicker, with very few thin roots being formed. 36Cl uptake into plantlets and transport to the leaves decreased in plants exposed to a high sucrose concentration. Acclimatization of jojoba plantlets was improved by enhancing ventilation.  相似文献   

4.
Summary

We investigated the dependence of in vitro rooting and acclimatisation to greenhouse conditions on the source of iron used in the shoot multiplication and rooting media using five raspberry (Rubus idaeus L.) cultivars (‘Beskid’, ‘Canby’, ‘Malling Seedling’, ‘Norna’, and ‘Veten’). Ethylenediamine di-2-hydroxy-phenyl acetate ferric (FeEDDHA) in the rooting medium led to higher chlorophyll contents, earlier and more abundant rooting (8.7 vs. 5.3 roots per shoot), 30% higher fresh and dry weights, and thus higher quality microplants than ethylenediaminetetra-acetate ferric sodium (FeEDTA). Higher quality microshoots had a beneficial effect on acclimatisation (i.e., percentage survival and length of shoots) when the microplants were planted in a peat-based substrate; however, when planted in vermiculite, the initial differences disappeared during a 4 week-long growth period in a greenhouse.  相似文献   

5.
There was no effect of irradiance level on surviving percentages of shoot tip explants of the pear rootstock BP10030, but low irradiance stimulated the initial growth of the explant. Irradiance had a strong effect on shoot multiplication. With an increase in photosynthetic photon flux (PPF) from 10 to 80 μmol m?2s?1, shoot number and length and shoot fresh and dry weights increased. The greatest number of shoots and the longest ones were obtained with a 16 h photoperiod, while the highest fresh and dry weight of shoots were produced with a 24 h photoperiod. Rooting percentage and the number of roots were markedly promoted under 80 μmolm?2s?1 PPF. Photoperiods of 8, 16 and 24 h produced similar effects on rooting percentages and the numbers of roots. Four to seven days of darkness were the optimum for rooting. Rooting percentage and the number of roots increased with increased temperature during darkness between 5 and 25°C. A further increase in dark temperature up to 30°C reduced rooting percentage and root number.  相似文献   

6.
Summary

Ashwagandha (Withania somnifera L. Dunal; Solanaceae) is being cultivated around the world mainly for its root which has rejuvenative properties. Field experiments during 1999–2001 under semi-arid tropical conditions of Hyderabad, India studied the effect of tillage depths (15 and 30 cm) and plant population densities (20, 40, 60 and 80 plants m–2) on root morphology, yield and quality and cultivation economics of ashwagandha. Preparatory tillage to 30 cm depth in combination with a density of 60 plants m–2 gave the highest root yield of 1.2 t ha–1 which was 50% higher than that following 15 cm tillage depth and the same density. This is attributed to the favourable effect of the former treatment leading to 33, 37 and 21% increases in plant height, number of branches per plant and shoot biomass yield, respectively. Further, this treatment produced most (68%) best quality root pieces. Main root length, length of lateral roots and diameter of lateral roots were significantly increased, while the diameter of main root and the number of laterals decreased. Furthermore, increase in plant density from 20–80 plants m–2 increased production of best quality roots from 42% to 59% under shallow tillage and from 53% to 71% of root yield under deep tillage. The implications of change in root morphology are discussed in the light of production of different grades of roots, their market preferences and economics. Deep tillage was equally advantageous for seed production, but plant population density for maximum seed yield (211 kg ha–1) was lower at 40 than at 60 plants m–2 for maximum root yield. Maximum gross and net returns and benefit-cost ratio occurred following the highest root yield.  相似文献   

7.
Adventitious shoot regeneration from mature cotyledons of GF677 rootstock (Prunus persica × Prunus amygdalus) was achieved in vitro. Thidiazuron (N-phenyl-N-1,2,3-thidiazol-5-yl-urea; TDZ) at 32 µM gave the highest percentage of cotyledons forming adventitious shoots (68.8%) and the highest number of shoots per cotyledon (4.8) on Quoirin and Lepoivre (QL) medium. On QL medium containing 32 µM TDZ, exposure of the proximal segments of cotyledons to darkness at the start of culture increased the percentage of cotyledons forming adventitious shoots (62.5%) when compared with those kept under light conditions (15%). A combination of 0.72 µM gibberellic acid and dark treatment resulted in at least 2.7-fold more elongated shoots than non-treated shoots. The highest rooting percentage (100%) occurred on 0.5× Murashige and Skoog medium supplemented with Gamborg (B5) vitamins and 2 mg l?1 indole-3-butyric acid. Rooted plantlets were acclimatised under greenhouse conditions with a 70% survival rate.  相似文献   

8.
Summary

Potted M.26 apple (Mahis domestica) liners were treated with the gibberellin biosynthesis inhibitor prohexadione-Ca (Apogee®) at 0 to 500 mg l”1 as a foliar spray. Apogee inhibited stem elongation, leaf formation, total leaf area and shoot dry weight, while significantly increasing specific leaf weight, root dry weight and root: shoot ratio, regardless of rate. Foliar application of gibberellin A4+7 (GA4+7) at 200 mg l”1 to Apogee-treated plants one day later reversed these effects, especially stem elongation, root dry-matter production and root: shoot ratio. Apogee increased N concentration in stems but not in leaves and roots. There was no effect on the pattern of N allocation amongst organs. GA4+7 increased leaf N concentration but decreased stem and root N concentrations compared with untreated controls, with N allocation shifting from roots to stem. Total nonstructural carbohydrates (TNC), expressed either on a concentration or content basis, increased in all parts of the Apogee-treated plants, due to increased levels of starch rather than soluble sugars, without altering allocation pattern. Conversely, GA4+7 reduced TNC levels (mainly starch levels) in all parts, with the pattern of allocation slightly shifted from roots to stem. The afternoon decline in stomatal conductance occurred earlier in the Apogee treated plants, measured 10 d after stem elongation had ceased. Starch buildup in the Apogee-treated plants appeared to be associated with this effect, suggesting an involvement of a feedback inhibition of photosynthesis in the Apogee-induced stomatal control.  相似文献   

9.
Summary

Optimal rooting conditions have been determined for shoot cultures of Camellia japonica cv. Alba Plena derived from a 50 year old tree: dipping the base of shoots in 1 g l?l solution for 15 min, followed by 12 days’ darkness, induced 87% rooting in shoots cultured with Woody Plant Medium (WPM) macronutrients. Halving the auxin concentration or exposure time considerably reduced this rate, and root formation was severely inhibited if an initial dark period for the entire shoot was not used. The type of support (agar or paper bridges) did not significantly affect the rooting percentage or number of roots per rooted shoot, but liquid media induced greater root elongation. No significant differences were observed between the use of WPM and a modified Heller’s medium as regards the rooting percentages achieved, but the number of roots formed was considerably greater with WPM, as was the survival rate after transfer to soil (70% for transfer as against 35% with the modified Heller’s medium). Best survival rates were achieved when shoots were transferred to the acclimatization soil 12 days after auxin treatment, i.e. immediately after the dark period.  相似文献   

10.
Summary

Passionfruit are grown in the tropics and subtropics where mean monthly soil temperatures at 15 cm range from about 10° to 30°C. The choice of rootstock can also influence production with most industries exploiting either the purple (Passiflora edulis f. edulis) or golden passionfruit (P. edulis tflavicarpa). We examined the relationship between shoot and root growth in purple x golden hybrid E-23 grafted onto golden passionfruit seedlings. Growth was manipulated by varying the volume of the soil available to the roots or temperature of the root zone. Shoot and root growth increased as root zone volume increased from 0.3, 1.4, 4, 12 to 24 1. Shoot weight (Ws) was correlated with root weight (WR):WS = 12.697 + 5.272 WR + 0.195 WR2 (r2 = 91%, P<0.001), with the plants allocating a smaller proportion of dry matter to the roots as root weight increased. Differences in shoot growth with pot volume were not due to changes in water or nutrient status. In the temperature experiment, the two critical root zone temperatures at 90% of maximum growth were about 20° and 35° C for vine extension, leaf area, node and leaf production, and 20° and 30°C for flower production. Leaf and stem dry weight were optimal between about 18° and 34°C, while maximum root growth occurred at 38°C. There was a weak relationship between shoot (Ws) and root dry weight (WR): Ws = ?19.346 + 24.500 WR ?1.046 WR2 (r2 = 53%, .P<0.001). Apparently, variations in shoot growth at different soil temperatures cannot be explained solely by differences in root growth. Reduced growth at 10°C was associated with lower chlorophyll concentration, stomatal conductance and net CO2 assimilation, but not lower leaf water potential. The concentration of most nutrients were lower at 10°C than at higher temperatures, but none was outside the range which would be expected to restrict growth. There appears to be a co-ordination of shoot and root growth as the soil volume available for root growth increases, whereas root temperature affects the roots and tops differently. The results of the pot volume experiment demonstrate the importance of rootstock vigour in passionfruit breeding. Productivity would be affected in cool subtropical areas with soil <20°C and in tropical areas with soil >30°C.  相似文献   

11.
Micropropagation of 12 raspberry seedling selections and the cultivar ‘Malling Jewel’ has been achieved. A basic culture medium (Linsmaier and Skoog, 1965) supplemented with benzylaminopurine (BAP), 1.0 mg l?1, and indol-3-yl butyric acid (IBA), 0.1 mg l?1, was optimal for shoot proliferation. The presence of phloroglucinol (PG) at a concentration of 162 mg l?1 significantly increased shoot number at all auxin: cytokinin concentrations. Removal of the cytokinin and increasing the concentration of IBA to 1.0 mg l?1 resulted in adventitious root formation. PG synergistically promoted the number of roots per rooted culture but did not significantly increase the percentage rooting. Viable plants were produced from all genotypes when transplanted to soil.  相似文献   

12.
The rooting ability of one-node leafy cuttings of Eucalyptus globulus decreased rapidly with distance from the (decapitated) apical node. The young and immature leaves close to the shoot apex usually promoted rooting whereas the apex itself had little effect or was detrimental. In apical cuttings with an equivalent complement of leaves, increasing stem volume (and woodiness at the base of the cutting) slightly reduced rooting. The swelling of the stem at the base of shoots from coppice or potted plants also reduced rooting when present at the base of the cutting, whereas the inclusion of the root/shoot junction of seedlings promoted rooting. Cuttings from small seedlings rooted well and the roots sometimes emerged directly from the stem, whereas in non-seedling cuttings, roots nearly always arose from callus. The survival of cuttings in the propagation environment varied between trials. In apical cuttings with the same leaf complement, survival tended to increase with woodiness at the base of the cutting, but in contiguous one-node cuttings this tendency was overcome by the leaves, the soft apical nodes surviving better than the more proximal woodier nodes.  相似文献   

13.
Summary

We have evaluated the influence of four different peach rootstocks (Prunus pumila,‘GF 655/2’ ,‘Missour’ and ‘GF 677’ as a standard) planted in medium-heavy to heavy soil on phenological events (flowering and harvest date), growth, yield, fruit quality and mortality of peach (P. persica L.) scions of cv. ‘Redhaven’. At the end of flowering, there were no significant differences between the different rootstocks in the years 1999, 2000, 2003 and 2004. In 2001, trees grafted on P. pumila reached the end of flowering 2 d before trees grafted on the other rootstocks. ‘Redhaven’ fruits ripened on the same day on trees grafted on the different rootstocks. The differences were only between years. The results showed that significantly less vigorous trees, according to their trunk cross-sectional area (TCSA) and canopy volume, with the lowest yield, were observed on P. pumila rootstock. The rootstock P. pumila had a significant negative influence on fruit dimensions and mortality was 50%. Trees grafted on ‘GF 655/2’ rootstock produced significantly lower yields than those grafted on ‘GF 677’ or ‘Missour’ rootstocks. Only the ‘GF 655/2’ rootstock had root suckers. Trees grafted on ‘GF 677’ rootstock were significantly more vigorous than on the other rootstocks, and produced the highest yield with good fruit quality. The final canopy volumes of peach trees grafted on the different rootstocks were very different. The most vigorous trees were those grafted on ‘GF 677’ rootstock, where the final tree volume was 12.8 m3. Trees grafted on P. pumila and ‘GF 655/2’ had significantly lower TCSA values than on the other rootstocks.  相似文献   

14.
谢启鑫  庄东红  吴奕恒 《果树学报》2007,24(2):157-161,F0003
以油柿下胚轴为材料进行了不定芽再生和再生苗生根的研究,旨在建立油柿的离体再生体系,为转基因操作奠定基础。结果表明,在所试验的所有培养基中,MS(1/2N)+IAA0.1mg/L+ZT2.0mg/L最适合油柿下胚轴培养,其不定芽再生率和外植体平均不定芽数最高,分别为81.7%和(5.3±2.1)个。再生苗接种于添加IAA和IBA各0.5mg/L的MS(1/2N)培养基上生根效果最好,生根率达100%,平均根数达(3.2±1.4)条,平均根长度为(2.4±1.0)cm,且侧根较多、植株生长迅速而健壮。再生苗生根后移栽,30d时成活率达96%。  相似文献   

15.
Summary

The influence of partial substitution of agar by galactomannans in culture media supplemented with different concentrations of indole-3-butyric acid (IBA) was studied on in vitro rooting of pear (Pyrus communis L.) cultivar ‘Durondeau’ and apple rootstock (Malus prunifolia Borkh.) cultivar ‘Marubakaido’. The galactomannans applied were obtained from Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum) seeds. The results obtained with mixtures of agar and galactomannan (3 g l–1 each) were compared with those from media solidified with a standard concentration of agar (6 g l–1). The rooting of pear shoots was enhanced significantly in the presence of a mixture of agar plus cassia galactomannan compared to medium solidified with agar only. The modified media promoted a higher number of roots than the control, and increased the percentage of rooted shoots. A maximum of 84.8% rooting was obtained on half-strength MS medium (1?2MS) supplemented with 0.49 µM IBA and solidified with a blend of agar plus cassia galactomannan. For the apple rootstock, only the number of roots per shoot was influenced significantly by the addition of galactomannan to the rooting medium. The highest number of roots per shoot was 16.67 on 1?2MS medium gelled with a mixture of agar plus guar galactomannan supplemented with 4.90 µM IBA. The behaviour of the agar-galactomannan gel and the possibility of reduced costs when compared with systems containing only agar, suggest new biological and commercial applications for galactomannans.  相似文献   

16.
Summary

We have developed a two-step procedure for rooting of tea microshoots in vitro. The effectiveness of different auxin treatments for root formation was found to differ. Among the auxins tested, 25 μM -naphthalene acetic acid (NAA) gave the best results, with 100% rooting, compared to 25 μM indole-3-butyric acid (IBA) or 25 μM indole-3-acetic acid (IAA), which induced 17% and 58% rooting, respectively. Incubation of tea microshoots on 0.33 Murashige and Skoog (MS) medium, supplemented with 25.0 μM NAA or 175.0 μM IBA for 10 d, followed by transfer to auxin-free 0.33 MS medium resulted in 100% rooting, whereas 50.0 μM IAA induced 91.7% rooting. Besides the different auxin treatments, the strength of the MS medium, the duration of incubation of microshoots in auxin-containing medium, the sucrose concentration, the gelling agent, the pH of the medium, the incubation temperature, the light intensity, and the quality of the shoots also played a significant role during in vitro rooting of micropropagated tea shoots. Among the combinations tested, the most effective results were obtained when green microshoots were incubated on 0.33 MS medium supplemented with 25.0 μM NAA, 50.0 mM sucrose, pH 5.5, gelled with 0.2% (w/v) PhytagelTM for 10 d at 25° – 30°C at a light intensity of 40 μmol m–2 s–1, followed by transfer of shoots to auxin-free 0.3 MS medium. This resulted in 100% rooting and, on average, 11 long roots were formed per shoot. Anatomical changes during adventitious rooting of micropropagated tea shoots in vitro were also studied to understand the process of rooting.  相似文献   

17.
The influence was investigated of irradiance on blackcurrant cv Baldwin shoot proliferation and subsequent rooting in vitro. Shoots were cultured under a range of irradiance levels between 0.9 and 28.4 Wm-2 and the rate of proliferation expressed as shoot doubling times (td), was lowest at 0.9 Wm-2 (td = 59.5 d) and rose to a maximum at 18.5 Wm-2 (td =14.8 d). Rooting was influenced by the light level during the proliferation stage of culture as higher light levels increased the time of root emergence. The shoot dry weight at the end of the rooting period was positively correlated with the light level during proliferation and negatively correlated with the time of root emergence.  相似文献   

18.
Summary

This is the first study to address the effects of permanent magnetic fields (MFs) on the in vitro growth of Phalaenopsis plantlets. Uniform Phalaenopsis Gallant Beau ‘George Vazquez’ plantlets, each with two leaves and two roots, and each approx. 2 cm in height, were excised from a mass of protocorm-like bodies (PLBs) after 3 months of sub-culture. The plantlets (n = 21) were cultured in a film culture system (‘Miracle Pack’®) under MFs of different intensity: 0.10, 0.15, or 0.20 Tesla (T). Each culture vessel at each MF intensity was cultured on the North (N) or South (S) poles of specialised magnets. The 0.15 T MF was also applied for different lengths of time (1, 2, or 3 months) at both the N and S poles. Control plantlets were simply exposed to the naturally-occurring geo-MF, and not to any induced MF. All MFs tested had a positive influence on shoot and root development, but did not influence chlorophyll contents. Among all the intensities and polarities of MF tested, 0.10 T – S had the greatest positive influence on specific growth parameters of Phalaenopsis plantlets such as maximum leaf length, root length, fresh weight and dry weight of shoots and roots, and leaf width. Constant exposure to a MF of 0.15 T for 3 months, at either the N or S poles, significantly enhanced the development of plantlets.The results obtained in this study indicate that MFs can have a positive effect on the efficiency and quality of clonal Phalaenopsis plantlets during commercial production. The MFs from commercially-produced permanent magnets enhanced Phalaenopsis plantlet growth significantly and can be used as a novel means to study the effect of MFs on plant growth and development, or to control morphogenesis in limited spaces such as space stations.  相似文献   

19.
Chestnut plants were proliferated in vitro from axillary buds of juvenile shoots. N6-Benzyl-aminopurine (BAP) at 0.1?0.5 mg l?1 was optimal for shoot multiplication. The important role played by the macronutrient formula on shoot multiplication, and especially on the rooting-stage, is emphasized. The MS (12 NO3) macronutrients gave the best rooting percentage as well as the highest number of roots per rooted shoot. In these experiments, shoots remained in the 3 mg l?1 indole-3-butyric acid (IBA) medium for 12 days, after which they were transferred to an auxin-free medium where roots developed fully. Optimum rooting was achieved by immersing the 1 cm basal end of shoots in concentrated IBA solutions (0.5?1 mg ml?1) for periods ranging from 2 to 15 min.  相似文献   

20.
SUMMARY

Rooting of leafless winter hardwood cuttings of the plum rootstock Prunus insititia ‘Pixy’ increased as the location from which the shoots were taken from within specially grown stockplants decreased in height above ground, associated with a parallel reduction in shoot thickness. However, the actual height of the least-ready-rooting crown cuttings had no effect on rooting, suggesting that relative rather than absolute position is important. Rooting was unaffected by bark-ringing and trunk incision distal to the shoot position, suggesting that such treatments did not interfere with a basipetally translocated root promotor which might have accounted for improved rooting of cuttings in the lower parts of the hedge. The rooting of crown cuttings above a bark ring was reduced considerably compared with that of cuttings from normal bushes, and this was associated with increased thickness of shoots distal to the ring. Delaying pruning in spring until after growth had started resulted in thinner crown shoots compared with those from plants pruned normally while dormant, and the rooting of these thinner crown shoots was much higher than that of the normal crown cuttings. It was shown by covariance analysis that shoot thickness accounted for part of the rooting response but could not account for the total effect due to shoot position within the bush, ringing, or time of pruning. Competence to root appears to develop independently in individual shoots, modified by a shoot thickness factor which favours the subordinate shoots induced in the shoot hierarchy of severely pruned hedges.  相似文献   

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