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1.
Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring‐sown white clover sward (three experiments) or during autumn, post‐cereal harvest, in an under‐sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.  相似文献   

2.
The three rhizomatous perennials Elytrigia repens, Equisetum arvense and Tussilago farfara are all problematic in Scandinavian agriculture, due to their low susceptibility to soil cultivation. While repeated soil tillage is a fundamental part of the integrated control of these species, it is highly energy consuming and inefficient during periods when little sprout regrowth occurs. Substituting cultivation with mowing will reduce the environmental impact and labour costs, but its efficiency will still depend on the capacity of plants to sprout. Therefore, we studied the seasonal pattern in emergence and rhizome biomass allocation from July to April in six populations for each of the species. Plants were grown outdoors in pots buried in soil and exhumed at regular intervals in a two‐year experiment. In all three species, biomass allocation to rhizomes continued until late in the autumn. Emergence was severely impaired in E. arvense and T. farfara in September–October, while in E. repens, there was no such reduction in the number of emerged shoots. However, in the latter species, the shoot/rhizome ratio decreased and remained low until the plants had been exposed to a period of low temperatures. The increase in shoot/rhizome ratio for E. repens coincided with the resumed capacity to emerge for E. arvense and T. farfara. These results imply that there is no need to repeat a defoliation of E. arvense and T. farfara, if carried out in September–October. However, removal of the aerial plant parts early in the autumn is important to interrupt the upload of storage compounds to the rhizome systems of all species.  相似文献   

3.
Elymus repens (L.) Gould and Agrostis gigantea Roth. raised from rhizomes both responded to reduced light intensity by increased stem length, while the number of aerial shoots was reduced. The weight of the aerial parts was not influenced by a 50% reduction of the daylight intensity, but a further reduction of light caused a significant decrease in weight. The production of new rhizomes was more influenced by shading than were the aerial shoots. The consequence was an increase in the shoot/rhizome ratio. The food reserve per bud measured as inter-node weight in E. repens and A. gigantea was reduced only with intensive shading, and the vitality of the rhizomes appeared independent of light intensity. Intensive shading in early as compared to late summer caused a reduction in the number and weight of aerial shoots, but not in the weight of new rhizomes. Light intensities equal to those found in a spring wheat crop allowed more E. repens growth than light intensities equal to those in a spring oat crop. E. repens raised from seeds and grown at light intensities equal to those found in a cereal crop, showed insignificant rhizome production.  相似文献   

4.
Two potential control methods for Elymus repens, which do not disturb the soil, are post‐harvest mowing and competition from under‐sown cover crops. Our aim was to quantify the effect of cover crop competition and mowing on E. repens and to evaluate the potential for combining the two methods. We present a two‐factorial split‐plot experiment conducted at three locations in Sweden, in two experimental rounds conducted in 2011–2012 and 2012–2013. A spring cereal crop was under‐sown with perennial ryegrass, red clover or a mixture of the two (subplots). Under‐sown crops were either not mowed, or mowed once or twice post‐harvest (main plots). This was followed by ploughing and a new spring cereal crop the next year. Mowing twice reduced autumn shoot biomass by up to 66% for E. repens and 50% for cover crops compared with the control, twice as much as mowing once. Pure ryegrass and mixture treatments reduced E. repens shoot biomass by up to 40% compared with the control. Mowing twice reduced rhizome biomass in the subsequent year by 35% compared with the control, while the pure red clover treatment increased it by 20–30%. Mowing twice and treatments including red clover resulted in higher subsequent grain yields. We concluded that repeated mowing has the potential to control E. repens, but a low‐yielding cover crop has insufficient effect on rhizome biomass. Clover–grass mixtures are of interest as cover crops, because they have the potential to increase subsequent crop yield and even at low levels they reduce E. repens above‐ground autumn growth.  相似文献   

5.
Without herbicides, the control of Elymus repens relies on intensive tillage, often in the form of repeated post‐harvest stubble cultivations followed by ploughing. This is costly and time‐consuming and also increases the risk of nitrogen leaching. Our aim was to quantify the controlling effect on E. repens of single and repeated cultivation and differing time of cultivation in relation to spring cereal harvest. A 2‐year experiment was conducted at two sites in the south and east of Sweden in 2011–2012 and 2012–2013. We compared no, single and repeated tine cultivation followed by mouldboard ploughing; the single cultivation was performed directly after harvest or 20 days after harvest; when repeated, the first cultivation was performed immediately or 5 days after harvest, followed by a second cultivation 20 days after harvest. Tine cultivation in combination with mouldboard ploughing resulted in 50–70% lower rhizome biomass, and increased average subsequent cereal yields by 0–130% compared with ploughing alone. Large E. repens populations appeared to be more efficiently reduced by tine cultivation than smaller populations. A single tine cultivation 20 days after harvest tended to result in a higher E. repens shoot density and more rhizome biomass in the subsequent year than tine cultivation directly after harvest. Additional cultivation 20 days after harvest did not improve control of E. repens or the subsequent cereal grain yield, compared with a single cultivation conducted directly after harvest. In conclusion, preventing the growth of E. repens during the early part of the post‐harvest autumn period was more important than starving rhizomes with repeated cultivations.  相似文献   

6.
Mechanical weed control of perennial weeds in organic crop production over long post‐harvest periods is incompatible with the establishment of cover crops for improving soil quality and preventing nutrient leaching. We suggest a new concept that comprises uprooting and immediate removal of vegetative propagules located within the plough layer to allow for quick re‐establishment of a plant cover. A field experiment comparing the effects of conventional practices (stubble cultivation) with different combinations of rotary cultivation (One, Two or four passes) and cover crops (none vs. rye‐vetch‐mustard mixture) on Elytrigia repens rhizome removal, shoot growth and suppression of a subsequent barley crop was examined in two growing seasons. Four passes with a modified rotary cultivator, where each pass was followed by rhizome removal, reduced E. repens shoot growth in barley by 84% and 97%. In general, the cover crop developed poorly and did not affect barley or E. repens. Barley yield was only affected by treatments in the first season, where yield was negatively correlated with E. repens shoot biomass. The concept has potential for the control of severe E. repens infestations, but future research aimed at identifying more effective smother crops and less intensive methods of rhizome removal is needed.  相似文献   

7.
Brandsæter LO, Fogelfors H, Fykse H, Graglia E, Jensen RK, Melander B, Salonen J & Vanhala P (2010). Seasonal restrictions of bud growth on roots of Cirsium arvense and Sonchus arvensis and rhizomes of Elymus repens. Weed Research 50 , 102–109.

Summary

The success of weed management aimed at depleting the regenerative structures of perennial weeds depends largely on the sprouting activity of rhizome and root buds. Seasonal variation in sprouting of these buds on Cirsium arvense, Sonchus arvensis and Elymus repens was studied for plants collected from Denmark, Finland, Norway and Sweden. At 2‐week intervals from July to October, 5‐cm fragments of roots or rhizomes were cut from plants grown in buckets and planted into soil in pots, half of which were placed immediately into growth chambers at 18°C for 4 weeks. The other half of the pots were initially placed in a dark room at 2°C for 4 weeks before being transferred to the same growth chamber, also for 4 weeks. During the growth chamber period, the numbers of emerged shoots in each pot were counted weekly. The sprouting activity of C. arvense and E. repens was relatively uniform during this period and bud dormancy was not apparent. In all ecotypes of S. arvensis, innate bud dormancy developed during the latter part of the growing season. For all three species, differences in sprouting readiness were found among ecotypes. The results imply that C. arvense and E. repens are more likely to be controlled by mechanical measures in autumn than S. arvensis.  相似文献   

8.
Fluazifop-butyl, haloxyfop and sethoxydim with adjuvant oil were applied for three successive growing seasons to established strawberries infested with Elymus repens. The weed was virtually eradicated by three applications of haloxyfop (0.8 kg a.e. ha?1) in successive years. A similar effect was given by five applications of haloxyfop (0.4 kg a.e. ha?1) and fluazifop-butyl (1.6 kg AI ha?1) in three growing seasons. Lower rates of haloxyfop and fluazifop-butyl, and a high rate of sethoxydim (1.6 kg AI ha?1) applied five times were less effective, the ground cover of E. repens shoots not being reduced by the end of the experiment although weight of living rhizome was only 10-30% of that on untreated plots. Fruit yields on treated plots generally reflected the level of E. repens control, but there was some evidence of crop phytotoxicity from herbicide treatments. During the experiment E. repens untreated plots increased from about 30-100% ground cover and reduced yield 13, 28 and 68% in successive years compared with weed-free plots.  相似文献   

9.
Growth inhibition of pot-grown Elymus repens (L.) Gould by fluazifop-butyl was occasionally enhanced by pre-treatment with ethephon. Studies with 14C-labelled fluazifop-butyl showed that ethephon increased the accumulation of 14C in basal buds and proximal parts of the rhizome system. This potential modification in the distribution of fluazifop-butyl within E. repens rhizomes may have reduced regeneration and recovery of the E. repens, particularly from the basal buds, although there was no increase in the proportion of 14C translocated into the rhizome. Also, ethephon not only activated the sinks in the rhizome but in the foliage of E. repens as well, and could initiate buds without sinks. The effects of ethephon on fluazifop-butyl phototoxicity were irregular in their occurrence and degree, and possible reasons for this are discussed. Effets depré-traitements à I'étéphon sur la réponse de Elymus repens au fluazifop-butyl Lors d'expériences en pots, des pré-traitements & 1'étéphon augmentaient occasionnellement 1'inhibition de croissance d'Elymus repens (L.) Gould traité au fluazifop-butyl. Des etudes avec du fluazifop-butyl marqué au 14C ont montré que l'éléphon augmentait l'accumulation de 14Cdans les bourgeons de la base et dans les parties proximales des rhizomes. Bien que la proportion de 14C transportée dans le rhizome ne soit pas accrue, cette modification de la distribution du fluazifop-butyl à l'intérieur des rhizomes d'E. repens pourrait limiter la régénération et la reprise de croissance, en particulier à partir des bourgeons de la base. En outre, l'étéphon activait des puits métaboliques non seulement dans le rhizome mais aussi dans le feuillage d'E. repens et pouvait initier des bourgeons qui ne se comportaient pas comme des puits métaboliques. Tant 1'existence que 1'intensité des effets de 1'étéphon sur la phytotoxicité du fluazifop-butyl étaient irréguliers et les raisons possibles en sont discutées. Wirkung einer Vorbehandlung mit Ethephon auf die Reaktion von Elymus repens (L.) Gould auf Fluazifop-butyl In Gewächshausversuchen war die Wuchshem-mung von Elymus repens durch Fluazifop-butyl gelegentlich durch eine Vorbehandlung mil Ethephon verstärkt. Untersuchungen mil 14C-Fluazifop-butyl ergaben, daß Ethephon die Ak-kumulation von 14C in basalen Knospen und proximalen Teilen des Rhizoms förderte. Die so mögliche Veränderung der Verteilung von Fluazifop-butyl in den Quecke-Rhizomen kann zu der reduzierten Regeneration der Pflanzen geführt haben, vor allem aus den basalen Knospen, obwohl insgesamt keine groBere 14C-Menge im Rhizom gefunden wurde. Ethephon aktivierte nicht nur die Sinks im Rhizom, son-dern auch in den oberirdischen Teilen und kon-nte zur Ausbildung von Knospen ohne Sinks führen. Die Wirkungen des Ethephons auf die herbizide Wirkung des Fluazifop-butyls war unregelmaßig, und die moglichen Grunde dafiir werden diskutiert.  相似文献   

10.
L Kui  F Li  G Moore  J West 《Weed Research》2013,53(5):370-377
Resource sharing through rhizomes of clonal plants supplements locally available nutrients to enhance recruitment and growth in resource‐limited environments. We investigated whether Arundo donax, an invasive clonal plant, can benefit from clonal integration. Sharing resources between ramets can facilitate resprouting from mowing, fire and herbicide treatments, but it is unknown whether clonal integration contributes to A. donax invasion success. Our first objective was to determine whether A. donax rhizomes transported water between ramets. Hydrogen isotopic–enriched water was applied on three 1 m diameter areas, and rhizome and soil samples were collected beyond the watering zone after 5, 24 and 48 h of the last watering. Logistic modelling indicated that water was able to move laterally at least 3.5 m. The second objective was to determine whether clonal integration enhanced growth and survival of A. donax ramets. We compared growth‐related responses in paired 1 m2 plots with severed and intact rhizomes. In the first 19 days, rhizome severing nearly doubled ramet density, while by 77 days, the intact rhizomes produced 67% taller stems with 49% greater diameter and showed higher survival rate after flooding. This study provides initial evidence that physiological integration could be an important mechanism in A. donax, which can enhance its competitive abilities, accelerate rates of encroachment and strengthen its capability to recolonise disturbed areas. Our results highlight an important consideration of clonal invasive species in weed management.  相似文献   

11.
Abstract

The effects of intraspecific competition on the growth, development and resource‐allocation of Panicum repens was studied under greenhouse conditions. Evidence of severe intraspecific competition and adjustments to plant growth as a response to stress caused by competition, was seen from fairly early stages. An eight‐fold difference in initial plant density per pot, did not produce a significant difference in the dry weight accumulation between densities by 16‐weeks. Increase in plant density resulted in a very significant decrease in dry weight accumulation on a per plant basis, as expected. In general, dry weight partitioning into rhizomes and inflorescences increased with time at all densities, with a concomitant decrease in the percent dry weight partitioned into roots and shoots. Under low density conditions more dry weight was partitioned into inflorescences than at higher densities, indicating a shift in resource‐allocation with changing density. However, the expected shift of dry weight partitioning towards rhizome production at the highest densities was not evident. Allocation of resources to rhizomes did not vary with density. Even the lowest density plants which were not subjected to competitive stress, and the plants at the highest density, all allocated about one fifth of their dry weights to rhizomes. Plants under the highest density stress showed a very significant reduction in the number of tillers they produced and tiller dry weights, on both per pot and per plant basis. The study provides several insights into the highly adaptive and competitive nature of the grass weed, which contribute greatly to its success as a species.  相似文献   

12.
Field and glasshouse experiments were conducted from 1995 through 1996 to evaluate application timing of asulam (methyl sulfanilylcarbamate) for torpedograss (Panicum repens L.) control in relation to plant age in sugarcane. Above‐ground shoots of torpedograss were completely controlled with asulam at 2–4 kg active ingredient (a.i.) ha?1 applied 60 or 80 days after planting (DAP) in artificially infested pots. But some newly developed rhizome buds survived after asulam application resulting in 1–25 and 76–100% or more regrowth in 60 and 80 DAP‐applied pots, respectively. Whereas the herbicide at 2–4 kg a.i. ha?1 applied within 60 DAP completely controlled above‐ground shoots, applied 80 DAP at 2 kg a.i. ha?1 it did not completely control the weed in the artificially infested field. Regrowth levels were 1–25 and 76–100% or more in 60 and 80 DAP‐applied plots, respectively. Asulam at 2–3 kg a.i. ha?1 applied 20, 40, 60 or 80 DAP in a naturally infested field completely controlled above‐ground shoots and regrowth levels were 76–100 or more, 51–75, 1–25 and 26–50% in these same DAP applied plots, respectively. The herbicide applied at 4 kg a.i. ha?1 caused chlorosis on younger sugarcane leaves (one‐leaf stage), but when applied at 2–3 kg a.i. ha?1, no injury symptoms were shown. The herbicide at 2–4 kg a.i. ha?1 applied within 60 DAP resulted in remarkably higher yield and shoot biomass of sugarcane than that applied 80 DAP. This study suggested that asulam at 2–3 kg a.i. ha?1 should be applied 60 days after planting for the maximum control of torpedograss regrowth and better yield of sugarcane. This study also indicated that torpedograss cannot be completely controlled with a single application of asulam in a naturally infested field because of rhizome fragmentation by cross plowing and distribution of rhizomes into different soil layers that require different times to emerge. The shoots emerging after asulam application could not be controlled. Another study is required to determine the interval between sequential applications of asulam for better control of torpedograss in a naturally infested field.  相似文献   

13.
Increased atmospheric carbon dioxide (CO2) and soil nitrogen (N) may confer competitive advantages to invasive species over native plant species. We conducted a two‐way factorial experiment, growing the model invasive plant Arundo donax in CO2 growth chambers to test how CO2 and N availability interact to affect plant growth and biomass allocation. CO2 was supplied at c. 400 mg L?1 and c. 750 mg L?1. N was supplied as ammonium nitrate at 640, 320 and 80 mg L?1. We hypothesised that the fertilisation effect of CO2 enrichment would offset limitations from N deficiency. The results indicated that A. donax plants grown with enriched CO2 and abundant N accumulated approximately 50–100% more biomass and allocated approximately 50% more biomass to rhizomes than plants grown under ambient CO2 conditions. Neither treatment affected the leaf area per unit mass (specific leaf area; SLA). Greater growth will likely increase A. donax's competitive potential, because increased rhizome biomass has been associated with increased stress tolerance and post‐disturbance resprouting capacity. The consistent SLA under all treatments suggests that A. donax has a morphological strategy that prioritises increasing leaf quantity over increasing individual leaves' photosynthetic potential. These results reveal the ecological strategies that contribute to the successful establishment, dominance and persistence of this invasive plant species.  相似文献   

14.
Experiments were undertaken to define the conditions under which seeds and seedlings of Agropyron repens and Agrostis gigantea may start infestations in cereal crops. When seedlings were planted early or late in spring wheat and spring barley, most growth of shoots and rhizomes was produced by Agropyron planted early in wheat. Late planting halved the amount of shoot growth and severely inhibited rhizome formation. In winter wheat given a moderate or zero amount of nitrogen fertilizer in spring, growth of the weed seedlings was slow. Rhizomes were not produced during the time the crop was growing but only after harvest. Agrostis made more growth than Agropyron in most treatments throughout most of the experiment. Late planting decreased growth more than in the spring cereals. Nitrogen fertilizer, although it had little effect on the amount of growth made by winter wheat, increased the growth of the early-planted seedlings but decreased that of the late-planted ones of both weed species. When planted into plots given nitrogen, more seedlings of both species died after late than after early planting. Clearly, the amount of growth and rhizome produced by seedlings of these two species will depend on the type of cereal, the time of emergence of the seedlings in relation to the cereal, and on other factors affecting the relative vigour of cereal and weed. Evidently, where the weed seedlings emerge early in weakly or moderately competitive cereal crops or when growth is unchecked in the cereal stubble, seedlings could give rise to infestations.  相似文献   

15.
Docks can be serious weeds of arable land and permanent grasslands where they can persist through well‐established root systems. A Rumex hybrid (R. patientia x R. tianschanicus; cv. OK‐2, Uteusha) has been planted as a forage and energy crop since 2001 in Czechia and has now become a new weed species. As its ecological characteristics are unknown, there is a need for improved knowledge for developing control measures and strategies. In 2010 and 2011, we performed a tube pot experiment to investigate above‐ground and below‐ground biomass growth dynamics and below‐ground biomass allocation of Rumex OK‐2. We compared the hybrid with Rumex crispus and Rumex obtusifolius during the vegetation season in the seeding year. Above‐ground and below‐ground biomass of Rumex species tended to increase from July to September. In the seeding year, flowering was recorded only for one plant of Rumex OK‐2 and 27.5% of R. obtusifolius plants, whereas R. crispus did not flower. The proportion of below‐ground biomass of Rumex species in the upper 30 cm was about 70–80%. The growth dynamics and allocation of below‐ground biomass of Rumex OK‐2 were more like R. crispus than to R. obtusifolius. These similarities indicate the potential of Rumex OK‐2 to become a troublesome weedy species, comparable with R. crispus.  相似文献   

16.
Absorption, translocation and distribution of 14C-glyphosate were examined in Agropyron repens (L.) Beauv. plants growing under field conditions in the autumn. Glyphosate absorption did not increase beyond 3 days after application, whereas translocation to the rhizomes continued up to 7 days after application. The translocated glyphosate accumulated more in new rhizomes than in older parts of the rhizomes. Ten per cent of the glyphosate translocated out of the treated shoot was recovered in younger shoots 7 days after application. Plants harvested the following spring contained less than 20% of the glyphosate originally applied. Although a growth cabinet experiment indicated that 34% of the glyphosate in the rhizomes of treated plants could be remobi-lized into new aerial shoots, considerably less was recovered in new, aerial shoots in the spring in the field-grown plants. Freezing experiments showed that glyphosate translocation to the rhizomes was only prevented when cold treatment caused visible damage to A. repens foliage.  相似文献   

17.
The physiological and biochemical mechanisms of organogenesis in Equisetum arvense have not been clarified yet. However, high concentrations of nitrogen have been shown to exert an inhibitory effect on in vitro tuber formation in E. arvense. The aim of this study was to clarify the influence of the form of nitrogen in a medium on in vitro organogenesis in E. arvense. Single‐node segments of E. arvense rhizomes were cultured in the test medium. The NH4‐N and NO3‐N concentrations of the test medium, respectively, were adjusted by adding NH4H2PO4 and KNO3 to the basal medium. The basal medium was a nitrogen‐free, modified form of White's medium. Vegetative shoots were newly formed in the test tubes for concentrations of NO3‐N and NH4‐N that exceeded 56 mg L?1. However, no rhizome was formed at NH4‐N concentrations exceeding 28 mg L?1. The number of newly formed tubers decreased at an NH4‐N concentration of 28 mg L?1 and no tuber was formed at NH4‐N concentrations exceeding 56 mg L?1. In summary, although the presence of NO3‐N in the medium did not inhibit in vitro rhizome or tuber formation in E. arvense, the presence of NH4‐N in the medium exerted a strong inhibitory effect on the in vitro formation of both of these organs.  相似文献   

18.
Increasing abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in pastures and meadows in western Norway has caused reductions in forage yield and quality in recent decades. Understanding plant development and regrowth following cutting is essential in devising cost‐effective means to control rushes. In a field experiment in western Norway, we investigated development of above‐ and below‐ground fractions of rush from seedlings to three‐year‐old plants, including the impact on vigour of disturbing growth by different cutting frequencies during the period 2009–2012. Each year, the plants were exposed to one or two annual cuts or left untreated and five destructive samplings were performed from March to early December. Juncus effusus showed significantly more vigorous growth than Juncus conglomeratus in the last two years of the study period. The above‐ground:below‐ground biomass ratio of both species increased mainly in spring and early summer and was reduced in late summer and autumn. Removal of aerial shoots also reduced the below‐ground fraction of both species. One annual cut in July effectively reduced biomass production in both species by 30–82%, which was only a slightly smaller reduction than with two annual cuts, in June and August. Mechanical control measures such as cutting can thus effectively reduce rush vigour when performed late in the growing season.  相似文献   

19.
Clonal species may benefit from human disturbance because their vegetative fragments may be distributed via soil. Solidago canadensis is an invasive rhizomatous perennial frequently found in ruderal environments. When creating new infrastructure, digging and cutting are two main factors that may influence the spread of S. canadensis into new areas. To have a better understanding of the invasive potential of S. canadensis, we investigated whether S. canadensis was able to survive and grow from stem cuttings as well as from rhizomes. Rhizomes and cuttings were collected from three populations in Eastern Norway. The rhizomes and cuttings were planted in a pot experiment to assess their vegetative ability to propagate. Rhizome fragments (5 and 10 cm long) were buried at 0.5, 10 and 30 cm depths. The cuttings were planted as 15 cm stems, with the bottom 5 cm pushed into the soil. The results showed that rhizome length did not have an effect on survival. Although some sprouting occurred at all burial depths, increasing depth had a negative effect on rhizome survival. In general, development of the cuttings was good, but there were differences between population performance and survival. These results imply that care must be taken when (i) constructing new sites, because digging and transport of soil masses may spread S. canadensis into new areas by rhizomes or cuttings, and (ii) mowing road verges and other ruderal areas to prevent the spread of stem cuttings from one area to another.  相似文献   

20.
A cytokinin-like effect of chiral 2-α-methylbenzylamino-4-alkylamino-6-chloro-1,3,5-triazines was found using a rhizome-inducing assay with Cyperus serotinus Rottb. tubers. C. serotinus tubers germinated in distilled water yielded plantlets with roots and leaves. Secondary rhizomes were normally not observed within the regular 14-day incubation time in water culture, whereas after increasing incubation periods a very short rhizome appeared (controls). 6-Benzylaminopurine (BA) significantly stimulated rhizome induction, while other plant hormones were inactive. The (R)-isomers of the 1, 3, 5-triazine compounds also stimulated induction of the rhizomes, whereas the (S)-isomers did not. The described rhizome induction system seems to be suitable as a cytokinin bioassay. The (R)-1, 3, 5-triazine compounds showing rhizome-inducing activity (RI activity) inhibited root formation and plant growth at high concentrations with symptoms which were very similar to those of BA. Therefore, the (R)-isomers appear to act as cytokinins in the rhizome induction assay.  相似文献   

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