Rhizome Buds Research Articles

In vitro clonal multiplication of turmeric (Curcuma spp.) and ginger (Zingiber officinale Rosc.)

Rhizome buds, excised from threeCurcuma spp., and ginger, inoculated aseptically on MS medium with varying levels of BAP and kinetin, produced multiple shoots. For shoot multiplication, a concentration of 3.0 mg/l BAP was found to be optimum for all the species.In vitro plants were successfully established in the field and were morphologically uniform. A simple method to extend the subculture interval was used and its relevance to germplasm conservation is discussed.

Torpedograss (Panicum repensL.) control with lower rates of glyphosate

Abstract The effect of glyphosate [N‐(phosphonomethyl) glycine] applied as foliar sprays, on the shoot growth, regrowth from ‘crown’ and rhizome bud‐viability of perennial torpedograss (Panicum repens L.) was studied. In general, rates of 1.0–4.0 kg a.i./ha killed 80–100% of aerial shoots and suppressed 90–100% of regrowth from treated plants. Rates above 1.0 kg a.i./ha also killed 80–97% of rhizome buds within 7 days of spraying. Rates below 1.0 kg/ha gave insufficient regrowth suppression and bud‐ kill and were not adequate to control well‐established, mature plants. Plant age was a factor which affected glyphosate control of the weed, and while the young plants under 8 weeks of age were effectively killed by lower rates, the killing of older plants up to 20 weeks of age required rates above 1.0 kg/ha. Although rhizome length was not a major factor influencing the killing of rhizome buds by a range of rates of 0.5–4.0 kg/ha, the results of several experiments indicated that a rate close to 4.0 kg/ha was...

Cold tolerance in sporobolus virginicus (L.) Kunth robust form, tissue cultures and whole plants

Abstract Sporobolus virginicus (L.) Kunth robust form, is a coastal C4 grass species in tropical and subtropical regions. An artificial freeze test was used to determine the response of tissue exposed to low temperature. The response was monitored by three methods: measuring respiration rates as carbon dioxide flux before and after freezing, conducting a triphenyl tetrazolium chloride (TTC) viability assay, and observing growth of tissue cultures and the regrowth of shoots and roots from rhizome buds. The TTC assay overpredicted the survival temperature in rhizomes, when based on a 50% of control as lethal value, but was a good indicator of survival in callus and suspension cultures. Respiration rates of callus tissue declined with low temperature exposure and paralleled the TTC results. Rhizome tissue however had a more complex respiratory response. High, post‐freeze, respiration rates during thawing of rhizomes at + 5.0°C were correlated with injury, detected both by a TTC assay and by the measurement of carbon dioxide flux. High respiration rates, measured after the thawing period, due to disabled rhizomes that were ultimately inviable, provide an explanation for the overprediction of the TTC assay. S. virginicus was found to be freeze‐sensitive, LT50= ‐ 2.5°C, with no hardening ability and it was concluded that cellular resistance defines the limits of freezing tolerance. However, avoidance of freezing strain through an underground perenniating organ probably allows S. virginicus to survive on the polar end of its range where episodic frosts may decrease temperatures to the lower limits of the cellular tolerance of a species.

Seed germination and seedling morphology of the seagrass, Halophila engelmannii (Hydrocharitaceae)

Seeds of Halophila engelmannii Aschers., that were collected in Redfish Bay, Texas, at weekly intervals from mid-May to mid-June 1986, began to germinate 3–4 weeks after collection. Most of the collections subsequently showed an increase in the rate of germination under increased light intensity and all had a stoppage of germination after transfer to darkness, indicating a light requirement to break endogenous seed dormancy. During the 5 weeks after seeds germinated, seedlings in soil culture produced a rosette of six leaves before the appearance of a rhizome bud in the axil of the third leaf. The first node of the rhizome produced a root and an upright shoot with a pseudowhorl of three to five leaves.

The Expanded Adaxial Epidermis of Equisetum Rhizome Sheath Teeth

Plants of Equisetum have an extensive rhizome system that produces nodal buds that grow into either aerial stems or branches of the rhizome. Certain species also have tuber buds. Both the aerial stems and the rhizomes of Equisetum have nodal sheaths bearing a crown of teeth. The sheath is interpreted as a whorl of fused leaves, with the teeth representing the free tips of the individual leaves. The buds consist of a series of superposed sheaths that overarch the shoot apex. Subsequent intercalary meristematic activity at the base of each nodal sheath separates the nodal sheaths and produces the internodes. The sheath teeth of the subterranean buds have a distinctive adaxial epidermis, a feature rarely noted in the literature. Francini (1942) compared rhizome and aerial buds of E. ramosissimum, and described trichomes developing from the inner epidermis of the rhizome sheath teeth and growing together to help the teeth form a cap protecting the apex. She also described mucilage production from the abaxial epidermis of the outer sheaths and pointed out how only one internode at a time elongates in the rhizome. Sachs (1882, p. 401) included a figure of a longitudinal section through an underground bud of Equisetum arvense showing an elaboration of the adaxial surface of the sheath teeth, but he did not describe this feature. Sadebeck (1902, p. 532) copied Sachs' figure, but did not mention the structure of the adaxial surface of the teeth. The purpose of this study is to describe more completely this little noted anatomical feature of Equisetum, and to speculate on its function.

Regrowth of Quackgrass (Agropyron repens) Following Postemergence Applications of Haloxyfop and Sethoxydim

Previous research has shown that haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} and sethoxydim {2-[1-(ethoxyimino)butyl-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} give less control of quackgrass [Agropyron repens(L.) Beauv. # AGRRE] when applied at the five- to seven-leaf stage compared to the three- to four-leaf stage. Current research indicates that reduced control of quackgrass in the eight-leaf stage, compared to the four-leaf stage, was not due to reduced herbicide retention on leaves or to changes in residual herbicide activity in the soil following postemergence applications. The efficacy of both herbicides on rhizome bud kill did not change between the four- and eight-leaf stages following application to the foliage. However, the efficacy of both herbicides on crown tissue bud viability was less at the eight-leaf stage. Rhizome sink intensity (the capacity to accumulate radiolabel) was similar at both stages of development following14C-haloxyfop and14C-sethoxydim application to either upper or lower leaves. Crown tissue sink intensity was significantly less at the eight-leaf stage compared to the four-leaf stage following14C-sethoxydim application to either upper or lower leaves and following14C-haloxyfop application to lower leaves. These data suggest that crown bud regrowth contributes substantially to reduced control of quackgrass in advanced stages of growth following applications of haloxyfop and sethoxydim.

HERBICIDE EFFECT ON THE VIABILITY OF QUACKGRASS (Agropyron repens) RHIZOME BUDS

Sethoxydim, glyphosate, haloxyfop-methyl, NCI 96683, fluazifop-butyl and RO 13-8895 were evaluated under controlled environment conditions for their ability to translocate from treated quackgrass shoots to rhizome nodal buds. Two techniques to evaluate rhizome bud viability were utilized. In general, more rhizome buds showed signs of respiratory activity as evaluated by the tetrazolium chloride assay than did those which showed evidence of bud growth when single buds were grown in an agar medium. Both bioassays indicated all the herbicides tested were more effective against younger (three leaf) plants than older (five leaf) plants. None of the herbicides tested completely eliminated either bud viability or the formation of new rhizome buds subsequent to treatment. The least effective herbicide tested was RO 13-8895. The most effective compounds were sethoxydim and haloxyfop-methyl. Glyphosate and fluazifop-butyl were of intermediate efficacy while NCI 96683 efficacy was between those two groups depending on the part of the rhizome being considered.Key words: Tetrazolium chloride, translocation, glyphosate, sethoxydim, haloxyfop-methyl, fluazifop-butyl

Progressive Kill of Rhizomatous Johnsongrass (Sorghum Halepense) from Repeated Treatment with Dalapon, MSMA, or Asulam

Space-planted johnsongrass [Sorghum halepense(L.) Pers. ♯ SORHA] was clipped back to a height of 26 cm after flowering and, when 45 to 61 cm in height, was treated with various rates of the sodium salt of dalapon (2,2-dichloropropionic acid), MSMA (monosodium methanearsonate), or the sodium salt of asulam (methylsulfanilylcarbamate). Treatments were reapplied as needed during the growing season whenever a majority of surviving plants in a plot had initiated new foliar growth. Most plants were not killed by a single application of any herbicide, although rhizome development, as measured by the number of rhizome buds, was inhibited by the initial herbicide treatments. MSMA at 4.5 kg ai/ha was more phytotoxic to johnsongrass than other herbicide treatments or MSMA at 2.3 kg ai/ha; a single application at the higher rate reduced the original number of rhizome buds on plants by 50 to 60%, and two applications killed 86 to 93% of the plants. Asulam at 4.5 and 6.7 kg ae/ha and dalapon at 6.7 and 9.0 kg ae/ha primarily controlled plants by inhibiting growth for an extended period. After two or three applications of asulam or dalapon at 6.7 kg ae/ha, only about 40% of the plants had been killed, but the original number of rhizome buds on surviving plants had been reduced by about 80%.

Effect of Leaf Girdling and Rhizome Girdling on Glyphosate Transport in Quackgrass (Agropyron repens)

Glyphosate transport was studied using the14C-labeled herbicide. Because glyphosate appears to undergo little metabolism in plants, detected14C was assumed to indicate the presence of glyphosate. Leaf-girdling experiments demonstrated that14C-glyphosate [N-(phosphonomethyl)glycine] transport in treated quackgrass [Agropyron repens(L.) Beauv. ♯3AGRRE] leaves occurred in both leaf symplast and apoplast. Symplastic transport was toward the leaf tip and the leaf base. Apoplastic transport was toward the leaf tip only. Rhizome-girdling experiments showed that translocation of glyphosate from a treated shoot to another shoot on the same rhizome occurs primarily in the rhizome symplast. Girdling the base of quackgrass culms showed that acropetal transport of glyphosate from the rhizome into quackgrass shoots is in the apoplast and the symplast of the culms of quackgrass shoots. Excision of rhizome buds and rhizome apices indicated that the rhizome is a sink for glyphosate independent of rhizome buds or rhizome apices. The concentration of14C-glyphosate in rhizome buds was less in plants with rhizome apices removed than in those with apices intact. The concentration of C-glyphosate in rhizome apices did not differ between plants with buds removed and those with buds intact.14C-glyphosate applied to a girdled rhizome apex remained primarily in the apex. Some transport of glyphosate past the girdle occurred, indicating apoplastic transport of glyphosate in the rhizome. Apoplastic transport of14C-glyphosate in the rhizome was greatest in water-stressed plants.

Effects of fluazifop‐butyl on shoot growth and rhizome buds of Elymus repens (L.) Gould

Summary:A series of glasshouse experiments was conducted to evaluate the activity of fluazifop‐butyl, butyl 2‐[4‐(5‐trifluoromethyl‐2‐pyridyloxy)phenoxy] propionate, against Elymus repens. Foliar applications of doses 0·25–1·0 kg ha−1 consistently gave better control than did soil applications. The most obvious phytotoxic symptoms were chlorosis and necrosis, beginning with the youngest leaves 5–6 days after spraying, which spread to all leaves within 2 weeks. Translocation was measured by defoliating plants at different times after spraying and assessing regrowth and by evaluating rhizome‐bud viability. At low doses (0·125 and 0·25 kg ha−1) translocation to rhizomes occurred mainly between 6 and 48 h. When fluazifop‐butyl was sprayed at a dose range of 0·125–1·0 kg ha−1, at least 90% of the rhizome buds had accumulated a lethal dose within 72 h of spraying. In another experiment, with a dose of 0·25 kg ha−1, 31, 72 and 92% of rhizome buds were found to be non‐viable when sampled 2, 24 and 48 h respectively after spraying. At 1·0 kg ha−1 all the buds had accumulated sufficient herbicide to prevent sprouting 48 h after spraying.

Effect of Soil Temperature and Moisture on Glyphosate and Photoassimilate Distribution in Quackgrass (Agropyron repens)

Experiments were conducted in growth chambers to evaluate the effect of soil temperature and soil moisture on the distribution of14C-photoassimilates and14C-glyphosate [N-(phosphonomethyl) glycine] in quackgrass [Agropyron repens(L.) Beauv. ♯3AGRRE]. When14C-glyphosate was applied to leaves, the radioactivity was less in the rhizome buds of plants exposed to 7-C soil temperature than in plants exposed to 12- and 18-C soil temperatures after 2 days. In plants with leaves exposed to14CO2, the radioactivity from14C-photoassimilates was greatest in rhizomes and rhizome buds of plants at the 12-C soil temperature. As soil moisture levels were decreased, uptake of C-glyphosate into leaves declined, and transport to the daughter shoots, rhizomes, and rhizome buds was reduced. The concentration of14C-photoassimilates in the rhizome system of water-stressed quackgrass plants was similar to that in nonstressed plants. This study shows that the patterns of glyphosate distribution differ from those of photoassimilate distribution in quackgrass plants exposed to water stress.

Studies on the mode of action of asulam in bracken (Pteridium aquilinumL. Kuhn)

SynopsisThe efficiency of bracken control using foliage-applied translocated herbicides depends upon the accumulation of a potentially lethal concentration of the active ingredient at the sites of action, the rhizome buds. There is evidence that the level of herbicide accumulation at these target sites is determined by a number of factors including the efficiency of cuticle penetration, absorption, translocation, metabolism and activity at the enzyme target sites. The level of metabolic activity of the rhizome/frond buds may be critical, dormant buds possibly receiving a sublethal dose. These buds may later become active and act as foci for reinfestation.The nature of these problems is discussed with particular reference to studies carried out on the mode of action of [14C]asulam.

Growth and Development of Quackgrass (Agropyron repens) Biotypes

Greenhouse and field experiments (at Rosemount and Roseau, Minnesota) were conducted to characterize the growth and development of 10 quackgrass [Agropyron repens (L.) Beauv.] biotypes selected near Roseau, Minnesota. The biotypes were highly variable for all traits studied. Eight of the biotypes had flag leaves approximately 1 cm wide, but two biotypes had flag leaves approximately 1.5 cm wide. Four biotypes were glaucous and blue-green in color, and the other biotypes varied from light to dark green and had varying leaf pubescence. In the field, plant height varied from 59 to 79 cm, and rhizome length varied from 105 to 135 cm. Spike production varied from 4 to 62 spikes per plant, and mid-season rhizome bud production varied from 246 to 1,211 buds, suggesting that the biotypes varied in their reproductive potential. Shoot dry weight varied from 48 to 362 g per plant, and daughter shoot production varied from 7 to 235 shoots per plant. The quackgrass near Roseau, Minnesota, appears to be made up of several distinct biotypes.

Some Biochemical Effects of Glyphosate on Plant Meristems

Glyphosate promoted the activity of phenylalanine ammonia lyase (PAL) in both single node rhizome buds of Agropyron repens and root tips of wheat seedlings, in the latter case correlating inversely with decline in respiratory activity. Differential rates of 14C-amino acid incorporation suggest that glyphosate depleted the phenylalanine protein precursor pool with resultant inhibition of protein synthesis, as evidenced by a rapid decline in the level of 'soluble' protein. Promotion of PAL is assumed to occur by derepression through decline in end-product levels. Activities of shikimate:NADP oxidoreductase (SORase), chorismate mutase, and polyphenol oxidase (PPO) were also elevated, but to lesser extents than for PAL.

Photoassimilate Distribution in Spartina alterniflora Loisel. II. Autumn and Winter Storage and Spring Regrowth1

AbstractVegetative regeneration of natural Spartina alterniflora Loisel. stands is critical to the stability and sustained productivity of Atlantic tidal salt marshes. Environmental conditions and human activity may limit the seasonal regeneration of energy reserves in perennial vegetative organs. Therefore, the use of energy stored in overwintering organs for vegetative growth in the spring was investigated. Leaf blades of mature flowering culms were exposed to 14CO2 during October. Entire plants were harvested during the ensuing winter and growing season. Distribution of 14C‐photosynthate in plants was measured by radioassay and radioautographic techniques. Approximately 50% of the late‐season photosynthate recovered from the plants had been translocated to basal organs, with rhizomes and tillers serving as major accumulation sites. During spring growth, almost half of the remaining stored 14C was translocated into tillers and plants emerging from rhizome buds. Shoots drew heavily upon stored energy sources through the fourth to fifth leaf stages of development. In mid‐summer, new rhizomes were regenerated largely by using energy stored in overwintered rhizomes. In S. alterniflora, energy transferred from one season to the next was utilized in suppport of early shoot growth and to produce organs which would serve as current season storage.

Control of Quackgrass (Agropyron repens) in Soybeans (Glycine max) with HOE 29152

In field studies, postemergence applications of HOE 29152 {2-[4-(trifluoromethyl phenoxy)phenoxy] propanoate} at rates of 1.68 to 3.36 kg/ha effectively controlled quackgrass [Agropyron repens(L.) Beauv.] when applied to plants in the one- to three-leaf stage. Control was still effective the following year. The addition of a surfactant to HOE 29152 did not increase quackgrass control, but it did increase soybean [Glycine max(L.) Merr.] injury. Cultivation 1 or 7 days after herbicide application increased the efficacy of HOE 29152 on quackgrass. Due to abundant moisture in 1977, untreated quackgrass-infested plots yielded as much as the weed-free plots. However, in 1976, a very dry year, the control of quackgrass with HOE 29152 resulted in greatly increased soybean yields. In greenhouse studies, postemergence applications of HOE 29152 at rates of 0.56 to 3.36 kg/ha effectively killed rhizome buds and reduced shoot dry weights of quackgrass. The phytotoxicity of HOE 29152 at 0.56 kg/ha was less at a postspray temperature of 36 C than at 17 or 27 C; however, the phytotoxicity of HOE 29152 at rates of 1.68 and 3.36 kg/ha was similar at all three temperatures. HOE 29152 can volatilize from soybean leaves, with volatility greater at 38 C than at 21 C. Postemergence applications injured soybeans similarly in field and growth chamber studies. Injury was observed only on leaves that were expanded at time of treatment, was short-term, and was most prevalent at 3.36 kg/ha.

Apical dominance in the rhizome of Agropyron repens. The relation of amino acid composition to bud activity

The polarity of bud growth in isolated, decapitated rhizomes of Agropyron repens L. Beauv. was correlated with the amino acid content of the buds and rhizome nodes and with the external N supply. In rhizomes from low-N plants grown under controlled conditions, the levels of asparagine and glutamine decreased markedly from the apical to the basal nodes and this gradient was closely correlated with a basipetal reduction in the growth of the rhizome buds. All other amino acids included in the analysis also showed a basipetal gradient of decreasing concentration but they were present in much lower concentrations than the amides and their correlation with bud growth was less precise. In high-N rhizomes collected in the field, the amino acid gradient was considerably reduced and the relatively uniform distribution of amide-N along the rhizome was correlated with a similar uniformity in growth of the rhizome buds.Increasing the N supply to intact plants released the lateral buds from inhibition. A significant growth response occurred within 48 h and was associated with a 30% increase in the amide-N content of the rhizome. Sprouting of buds on isolated nodes resulted, within 48 h, in a 42% reduction in the amide concentration in the node, as compared with nodes from which the bud had been removed and in which considerable amide accumulation occurred. Significant reductions in proline, serine, and alanine were also recorded.It was concluded that, under N-deficient, low water stress conditions, the inhibition and polarity of bud growth is mainly determined by the N supply, whereas, the relatively high concentrations of amino acids found in the fully inhibited buds of field rhizomes suggested, in accordance with previous results, that water rather than N was more likely to be the limiting factor under field conditions.

Studies on the mode of action of asulam in bracken (Pteridium aquilinum L. Kuhn) II. Biochemical activity in the rhizome buds

Summary:The effect of asulam (methyl (4‐aminobenzenesulphonyl) carbamate) on the synthesis of RNA and protein was investigated in bracken sporeling plants and excised rhizome bud tissue. Foliage application of asulam (4.4 kg/ha) reduced the RNA levels in frond buds and young fronds within 3 days, while protein levels were significantly reduced after 14 days. A significant reduction in respiratory activity of buds was observed after 2 weeks, the level of inhibition being 54% after 8 weeks. During a 3‐h incubation period, O2 uptake by excised bud issue was stimulated by 5 and 10 ppm asulam and inhibited by higher concentrations; 32P uptake was inhibited at all concentrations. Asulam (5 ppm and above) inhibited bud growth and reduced RNA and protein levels in incubated buds (20 h at 30°C), and the incorporation of [14C]orotic acid into RNA and [14C]leucine into protein. Reduction of RNA levels and inhibition of [14C]ladenine incorporation into RNA in buds occurred entirely in the ribosomal and supernatant fractions of the cellular extract. Inhibition of RNA synthesis by asulam (50 ppm) as measured by [14C] orotic acid incorporation into RNA was completely antagonized by CEPA (3‐chloroethylphosphonic acid) (50 ppm) and partially by 2,4‐D (2,4‐dichlorophenoxyacetic acid) (50 ppm) and GA (Gibberellic acid) (50 ppm). These results suggest that the interference of asulam with RNA and protein synthesis at the metabolically active sinks (rhizome buds) could be one of its major mechanisms of action in bracken.

Glyphosate Translocation and Quackgrass Rhizome Bud Kill

The effect of quackgrass [Agropyron repens (L.) Beauv.] rhizome length and foliage height on glyphosate [N-(phosphonomethyl)glycine] translocation was determined on the basis of bud kill and 14 C-accumulation in quackgrass rhizomes. Foliar glyphosate treatments of 0.28 kg/ha resulted in significantly reduced quackgrass rhizome bud survival, and rates of 0.56, 0.84, and 1.12 kg/ha gave nearly complete bud kill. Rhizome buds on glyphosate-treated quackgrass plants with 20 to 90 nodes had a higher survival rate than rhizome buds on plants with 10 nodes. Quackgrass bud kill was greatest when glyphosate was applied to taller foliage. When all rhizome buds were not killed, those closest to the mother shoot survived glyphosate treatments. The 14C accumulation following applications of 14C-glyphosate was greatest in nodes near the rhizome tip and least in nodes near the mother shoot. This suggests that greater bud kill near the rhizome tip was due to larger accumulation of glyphosate in this part of the rhizome.

Aerial plantlet formation in Asparagus officinalis L.

Removal of rhizome buds from asparagus plants grown in pots led to the formation of aerial plantlets from the nodes on the lower portion of shoots. A similar development was observed in vitro in cultured plantlets derived from bud explants if left for a sufficient length of time in culture. Aerial plantlets which developed either in vitro or in vivo could be detached and established in soil. These plants were morphologically indistinguishable from normal asparagus seedlings.