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- Author or Editor: Alan R. Langille x
Abstract
Foliar applications of 22NaCl solution to American arborvitae (Thuja occidentalis L.) and white spruce (Picea glauca L.) resulted in higher tissue accumulation of 22Na than soil applications for both species. Stem and needle tissue of spruce had higher 22Na content than corresponding tissues of arborvitae. Arborvitae roots, however, had a higher 22Na content than spruce. When foliarly applied, 22Na content of arborvitae was not influenced by date of salt application. In spruce, however, 22Na content increased as spring approached.
Abstract
Soil and hemlock needle samples obtained in Fall, 1972 at various distances from the edge of a newly-opened section of Interstate-95 were analyzed for Na and Cl and compared with samples taken from the same locations the following year. Soil Na was significantly increased to distances of 12 m from the highway's edge after the salting season while soil Cl was increased to a distance of 61 m. Both Na and Cl increased significantly in needle tissue at distances up to 61 m after one salting season.
Abstract
Although ethephon did not influence number of primary rhizomes on potato cv. Katahdin in growth chambers, the 500 and 1000 ppm treatments significantly increased the number of secondary rhizomes. Length of primary rhizomes was increased by the 50 ppm treatment. Number of primary tubers per plant decreased with increasing ethephon concn. Total tuber wt per plant was significantly reduced by all ethephon treatments, except 10 ppm which did not differ from controls.
Non-induced Katahdin potato plants were treated with three anti-gibberellins: CCC, BAS-106 and BAS-111. Other plants were sprayed with GA3 and placed in an inducing chamber. All treatments were repeated the following week. After final treatment, apical, sub-apical, medial and basal leaf bud-cuttings were taken from each plant and placed 1n a mist chamber. After two weeks, cuttings were examined for tuberization. BAS-111 and CCC were associated with 3.5 and 2 fold increase, respectively, in tuberization of cuttings over the non-induced control. Although induced control cuttings exhibited 100% tuberization, application of GA to plants grown under identical conditions, reduced tuberization 20 fold. In non-induced control cuttings and those treated with CCC, basal cuttings tuberized significantly better than those taken from higher on the stem. This pattern was reversed for plants treated with BAS-111. These results will be discussed in light of current understanding of the tuberization phenomenon.
In order to determine the appropriate nutritional conditions for survival, mesophyll protoplasts cv. “Russet Burbank” were cultured in three cell layer media. Each contained the MS macronutrients at either 0, 1 or 4 times the concentration recommended by Shepard (1980). During the 14 day culture period, cells were evaluated and counted, diameter determined and plating efficiency calculated. Results will be discussed.
The N.T.E.P. fine fescue test was established in Sept. 1994 in the Turfgrass Experimental Plot Area of the Littlefield Ornamental Trial Garden on the Univ. of Maine campus. The test consisted of 59 cultivars seeded in a randomized complete-block design with three replications. Following soil preparation, the Marlowe fine sandy soil was amended with lime and starter fertilizer according to soil test recommendations. Seeding was facilitated using a 5 × 3-ft plywood box to eliminate wind drift, and seed was raked in by hand. The study was conducted in a shade-free location with a maintenance fertility program of N at 0.6 lb/1000 ft2 per month of growing season using a slow-release commercial 20-5-15 fertilizer. Supplemental moisture was supplied as needed using an in-ground irrigation system. Mowing was initiated in May 1995 at a height of 2.5 inches and reduced to maintenance height of 2 inches for the duration of the 3-year test. Visual turf quality, turf density, color, weediness, and disease ratings were made monthly during each growing season and were statistically analyzed. Cultivars Darwin, NJ F-93, Columbra, Florentine, and the Banner II and III series were ranked as the best performers in the early- and late-season evaluations. BARFRR4ZBD, Jasper, Defiant, Silverlawn, Treazure, SR 5100, and Spartan were cultivars that performed well in early summer; however, during August, all cultivars showed depressed quality scores and no differences were observed. With the onset of true autumn conditions in October, the number of excellent performing cultivars approximated the same number observed in the spring. These results confirm that a number of fineleaf fescue cultivars are now available whose performance begins to rival Kentucky bluegrass under Maine conditions and will certainly provide better long-term turf than will perennial ryegrass.
`Katahdin' potato plants were grown under conditions that did not induce tuberization (noninducing conditions) and the foliage was sprayed with either a growth retardant (BAS-111) at 1000 mg·L-1 or distilled water. Other plants, grown under tuber-inducing conditions, received a foliar spray of gibberellic acid (GA3) at 100 mg·L-1 or distilled water. After 1 week, treatments were repeated. Two-node stem segments were excised from the apical, subapical, medial, and basal sections of each plant 72 hours after the second foliar treatment, disinfested, and inserted into flasks containing 50 mL of Murashige and Skoog medium (2% sucrose). After 3 weeks in a darkened incubator adjusted to 24 °C, tuberization response was evaluated. Orthogonal contrasts revealed significant differences between induced and noninduced controls for tuber number, diameter, and fresh mass. BAS-111 reduced rhizome length and increased tuber number, diameter, and fresh mass. GA3 increased rhizome length, but reduced tuber number, diameter, and fresh mass. Node location influenced tuber development, as basal explants produced significantly more and larger tubers, as well as longer rhizomes, than did apical explants, and subapical segments produced more and larger tubers than did apical segments. There were no significant differences between medial and basal nodal segments with respect to tuber number or tuber/rhizome size. Chemical names used: 1-phenoxy-5,5-dimethyl-3-(1,2,4-triazol-1-yl)-hexan-5-ol (BAS-111); 2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-carboxylic acid 1->4 lactone (GA3).
Abstract
Protoplasts were isolated from potato Solanum tuberosum L. leaves (‘Russet Burbank’) and plated in cell layers containing either BA, kinetin, or 2iP at concentrations of 0, 0.005, 0.05, or 5.0 mg·liter−1. After 17 days in culture, plating efficiencies were determined and BA at the 0.5 and 0.05 mg· liter−1 concentrations was associated with significantly higher plating efficiencies than the other two sources. The methodology for following development of individual protoplasts is discussed. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); and N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP).
Disinfested, etiolated medial segments of potato (Solanum tuberosum L.) sprouts cv. Katahdin with two axillary buds were placed on Murashige and Skoog (MS) medium in clear plastic culture boxes. Basal ends of explants were inserted into MS medium containing BA at 2 mg·liter–1. Nine treatments, composed of factorial combinations of GA3 at 0, 0.2, and 2 mg·liter–1 and IAA at 0, 0.3, and 3 mg·liter–1, were imposed. These were applied via small agar cylinders placed on the apical cut surface of each segment. Regardless of the presence of cytokinin and auxin, no rhizomes developed after 3 weeks in culture without a supply of GA3. Number and length of primary and secondary rhizomes increased with an increase in GA3 concentration in the agar cylinder from 0 to 2 mg·liter–1. Rhizome initiation and development appear to be controlled by coordinated participation of endogenous plant hormones during the early events leading to tuber development. Chemical names used: 2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-carboxylic acid 1->4 lactone (GA3); indole-3-acetic acid (IAA); N-(phenylmethyl)-1H-purin-6-amine (BA).
To explore further the role endogenous gibberellins play in the formation of the potato tuber, a gibberellin-deficient dwarf of Solanum tuberosum subsp. andigena (PI 281036) and its normal sibling were used in this study. Because gibberellins are known to be elevated and to affect tuber formation negatively when potato plants are grown under long day conditions, test plants were first grown in a growth chamber under conditions that did not favor tuberization (noninducing conditions). The stem apices of dwarfs received weekly applications of a 100-ppm gibberellic acid (GA3) solution to achieve growth similar to that of normal plants. When the requisite height was achieved, five dwarfs and five normal sibs were treated to foliar runoff with a 100-ppm GA3 solution, and a like number of these plants received a control spray of distilled water. These plants were then placed in a growth chamber adjusted to inducing conditions for tuber initiation. An additional five dwarfs and five normal sibs were sprayed with 600 ppm paclobutrazol (PB), a gibberellin inhibitor, and a similar number of plants received a distilled water control spray. This group of plants was returned to the noninducing chamber. After 1 week, plants were removed from their respective growth chambers and divided into two-node apical, medial, and basal leaf-bud cuttings. Basal buds of the cuttings were buried in moist potting mix in a mist chamber with a 16-hour photoperiod. Rhizome and tuberization responses were evaluated after 3 weeks. The experiment was repeated and results combined for statistical treatment. Orthogonal contrasts revealed that apical cuttings from normal donor plants produced rhizomes only under noninducing conditions or when treated with GA3. No rhizomes formed on apical cuttings from normal plants growing under inducing conditions (favoring tuberization) or noninduced plants receiving PB (a gibberellin inhibitor). For apical dwarf tissues, there were no effects of treatments on rhizome production, except for the PB treatment, which resulted in shorter rhizomes. Tuberization was observed in apical tissues of induced and noninduced dwarfs, which lack the ability to synthesize gibberellin, but only in induced cuttings of normal sibs. Noninduced dwarf cuttings tuberized as well as those from normal plants receiving the antigibberellin treatment. Tuber weights from induced apical cuttings of dwarfs and normal sibs were not significantly different. These results support the significant role played by gibberellins in tuber formation.