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Abstract

Developmental anatomy of interlocular cavitation (IC), defined as the formation of cavities in soft parenchymatous endocarp cells between seed locules, was studied in pods of several snap bean cultivars grown under various cultural and environmental conditions during the years 1969–1972. IC occurred in pods from the stages of rapid pod elongation (6–10 days after anthesis) until the time of pod senescence. Unbalanced swelling of endocarp tissues combined with decreased periclinal cell division and rapid cell elongation are concluded to be the causes of IC. In the most commonly observed form, IC also includes the separation of fused endodermal cells. Pod malformation is greater in pods with severe IC and such pods exhibited more quality defects after processing. Sequential development of this developmental and physiological disorder is illustrated.

Open Access

Abstract

Levels of root-promoting substances from Pelargonium hortorum Bailey were detected by the mung bean rooting bioassay. Fractionated ethanolic extracts from Pelargonium showed 1 major and 2 minor zones which promoted rooting of mung beans. The active fractions promoted rooting in the absence of indoleacetic acid (IAA), in contrast to results previously published. Levels of promoters fluctuated during the propagation period, decreasing to a low point just prior to root initiation. Active zones from extracts of Pelargonium treated with 2500 ppm succinic acid-2, 2-dimethylhydrazide (daminozide, SADH) did not differ from those of controls indicating that daminozide does not promote rooting by modification of the level of ethanolic extractable root promoters.

Open Access

Abstract

The propagation method and vegetative condition of ‘Northblue’ blueberry (Vaccinium corymbosum L.) stock plants influenced microshoot production in vitro and root formation on leaf-bud cuttings. In tissue culture (TC), explants from TC-derived stock plants produced longer shoots than explants from leaf-bud, standard- (ST-) derived stock on either Zimmerman’s (Zimm) medium at pH 4.8, Lloyd and McCown’s woody plant medium (WPM) at pH 4.8 or pH 5.2. Microshoots from explants of TC-stock plants also rooted more readily. Microshoot rootability decreased after 18 weeks on medium containing 68.6 μmol (12 mg/liter) 2iP. Microshoot production and rootability increased after 3 additional weeks on Zimm medium without 2iP present. Leaf-bud cuttings of ‘Northblue’ TC-stock plants treated with 5% and 10% concentrations of a commercial rooting compound (Dip-n-Grow) had a slightly higher rooting percentage and root rating than nontreated cuttings from ST-stock plants. However, cuttings from ST-stock plants of the same age showed larger increases in root formation and percentage of rooting in response to the same rooting compound treatments. Leaf-bud cuttings from vegetative TC-stock plants that developed shoots had more basal branches than those from floral ST-stock plants. Branch elongation was greatest and basal branches fewest on cuttings from floral ST stock plants. Successful propagation with cuttings and in vitro explants may be related to the condition of the stock plants, which have been altered by their own propagation methods and the plant growth regulators applied. Chemical names used: 1H-indole-3-acetic acid (IAA); 1H-indole-3-butanoic acid (IBA); 1-naphthaleneacetic acid (NAA); N-(3-methyl-2-butenyl)-2H-purin-6-amine (2iP).

Open Access

Abstract

Yields of tomato cultivars ‘Heinz 1350’ and ‘Delaware 65S3-2’ (a mid-season processing variety) were increased by foliar sprays of succinic acid 2,2-dimethyl hydrazide (Alar) and 2-chloroethyl trimethylammonium chloride (Cycocel). The most effective treatments were those in which 2500 ppm Alar was applied at the first or fourth true leaf stage of growth or at both of these times. Concentration of harvest was improved and early yield was increased by subsequent application of 5000 ppm Alar as a flower “cut-off” spray after desired fruit set had been achieved. The latter treatment has desirable implications for mechanical harvesting, since it virtually eliminated green fruit “pick-out” and slowed vegetative growth, thus causing a more concentrated harvest because of more rapid fruit maturation.

The yield increases are attributed to a combination of effects including resistance to water and heat stresses, more flowers per cluster and thus more fruits per plant. Additional hormone-like effects of Alar and certain Alar analogs were observed.

Open Access

Abstract

Herbaceous cuttings dipped momentarily in solutions of several concentrations of B-Nine produced significantly greater weight and numbers of adventitious roots than did untreated cuttings. Concentrations of 1000 ppm and 5000 ppm were effective, with 2500 ppm optimum. Conversely, similar treatments of Cycocel caused a marked depression of adventitious root production. As rate of Cycocel was increased, production of adventitious roots diminished, suggesting corroboration of research proposing Cycocel’s behavior as being that of an “anti-auxin”.

Open Access

Abstract

N-phenyl-N′1,2,3-thiadiazol-5-ylurea (thidiazuron) and several substituted pyridyl phenylurea compounds have been demonstrated to stimulate in vitro meristem and shoot formation at unusually low concentrations. These compounds appear to have strong cytokinin-like effects on a wide range of species and on species that respond little to conventional cytokinins. Thidiazuron has been reported to stimulate shoot proliferation in several woody species (e.g., Acer and Malus). The addition of 0.5μm N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) to the culture medium caused dramatic shoot number increases in hardy dedicuous azaleas (Rhododendron sp.) cultured in vitro. In petunia (Petunia ×hybrida Hort. Vilm.-Andr.) leaf test systems both thidiazuron and CPPU caused greater proliferation when used as explant dips or in the medium than similar treatments with N-(phenylmethyl)-1H-purin-6-amine (BA). Further possible applications and roles for these compounds are discussed.

Open Access

Terroir embodies a defined place, integrating soils, geology, climate, the cultivar, and the role of cultivation, culture, and history in producing wine (Wilson, 1999; White, 2003).The understated topographic changes, thick loess soils, diffuse climatic boundaries (humid to arid), and brief viticultural history contribute to a misconception that “terroir” may not be applicable or that niche microclimates for vineyards may not exist in Nebraska. With many new cultivars and selections now available that are adapted to growing environments once considered marginal vineyard settings and the wealth of geospatial resource databases (soils, climate, and topography) available, we have begun to combine traditional field cultivar evaluation studies with the geophysical data to determine appropriate site/cultivar suitability. Our data have shown that cultivars that were previously considered unlikely to be successful may be suited to viticulture in specific locations, e.g., Riesling, Lemberger, Cynthiana/Norton, Vignoles, and Chambourcin in southeast Nebraska (our “vinifera triangle”). Mean hardiness ratings (scale 1 to 9, where 1 = dead and 9 = no injury) have been obtained for more than 50 cultivars and selections, ranging from 1.86 for Viognier to 8.66 for Frontenac and 8.71 for Saint Croix, for example. Data for most of the cultivars under test will be presented and matched with “terroirs”, providing growers with a vineyard decision support system that can help match genotypes to their specific vineyard sites and help avoid poor cultivar selection.

Free access

RAPD and phenotypic analysis were conducted to assess clonal stability of hazelnuts generated from axillary buds cultured in vitro for long-term. The nuts produced on in vitro-propagated plants were indistinguishable from those of donor plants. With the exception of rare horizontal (plagiotropic) growth, all in vitro-propagated plants exhibited phenotypes similar to those of donor plants. RAPD analysis did not reveal any somaclonal variation between donor plants from which in vitro cultures were initiated and micropropagated plants (6-year cultures), and no somaclonal variation was detected among in vitro-propagated plants. However, polymorphism (15.6%) was detected between the parent plant and its in vitro-propagated progenies (from seedlings). These results show a good discriminatory power of RAPD to detect polymorphism between samples where it is expected, and it can be effectively used for genetic assessment of micropropagated hazelnut. No evidence of genetic or epigenetic changes was observed in long-term cultured hazelnut, and thus long-term in vitro culture of hazelnut does not seem to limit its clonal propagation.

Free access

Rosemary Rosmarinus officinalis is a member of the Lamiaceae. Rosmarinic acid (RA) is a very strong antioxidant produced in the chloroplast, and used to protect plant tissues against oxidative stress. A number of investigations showed that the sucrose concentration in the callus growing medium greatly influenced the production of secondary metabolites of the phenylpropanoid pathway such as RA. The aim of this study was to test the effect of elevated sucrose concentrations (2%, 3%, 4%, 5%, and 6% sucrose) and the effect of light and dark treatments on the production of RA in the callus of five different genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill, and APR. It was found that the dark treatment produces more RA than the light treatment in all genotypes, and in all sucrose concentrations. The RA concentration increased with increasing the sucrose concentration from 2%—reaching the highest concentration at 4% and 5% in most genotypes. The RA concentration declined again at 6% sucrose in all genotypes. We concluded that for the extraction of RA from rosemary callus it is preferred to be produced in the dark—this will save energy and will produce more RA than the light treatment. Also it is preferred to use sucrose concentration at 4% for genotypes Rosmarinus officinalis, Pine Scented, and APR; and 3% sucrose for genotype Madeline Hill in the dark condition. While for the light condition, it is preferred to use 5% sucrose with genotypes Majorca, Rosmarinus officinalis, Pine Scented, and Madeline Hill; and 4% sucrose for genotype APR.

Free access

Phenylalanine ammonia-lyase (PAL) enzyme is the most extensively studied enzyme in the phenylpropanoid pathway. Studies on the biosynthesis of rosmarinic acid (RA) showed that the PAL enzyme catalyzes the initial step of the phenylpropanoid pathway. The increase in RA content in plant tissues in vitro coincided with the increase in PAL activity. The aim of this study was to investigate the activity of the gene responsible for the production of the PAL enzyme in the five rosemary genotypes; this will give more understanding about the accumulation of rosmarinic acid in the five rosemary genotypes. The genotypes were Majorca, Rosmarinus officinalis, Pine Scented, Madeline Hill and APR. Northern blot hybridization between the PAL gene primer and the five genotypes' cDNA showed bands at 300 bp in all the five genotypes for the PAL gene. The expression of the PAL gene was high in genotypes Majorca, Rosmarinus officinalis, and Madeline Hill, while the expression was low in genotypes Pine Scented and APR. It was expected that the genotypes having the highest PAL gene expression will produce the highest amount of RA, but the highest genotype in PAL gene expression Madeline Hill had the lowest RA production in their leaves. This could occur due to the tissue specific regulation inside plant tissues. Inside the callus tissues, where the specific tissue regulation no longer exists, the RA was produced in repetitively large amounts in genotypes with high PAL gene expression.

Free access