Search Results
The hybrid origin of 23 rose (Rosa spp.) accessions was examined with three isozymes: acid phosphatase (E.C.3.1.3.2), malate dehydrogenase (E.C.1.1.1.37), and phosphoglucose isomerase (E.C.5.3.1.9). All three isozymes were useful for interspecific hybrid verification. This procedure was effective if the putative parents were known and differed in isozyme phenotype. To verify the origin of hybrid species or cultivars with hybrid origins, isozymes were useful but limited by the number of generations since the original hybridization and the number of accessions of the putative parental species assayed.
Isozyme analysis has been used for cultivar identification, but little has been done with the genus Rosa. One hundred and sixty rose accessions (species, cultivars, and hybrids) were characterized for isozyme phenotypes using starch gel electrophoresis. Six enzyme systems were stained on three electrode buffer systems. ACP, MDH, and 6PGD were run on morpholine citrate (pH 6.1) and histidine (pH 5.7), PGI and PGM were run on histidine (pH 5.7) and lithium borate (pH 8.3), and SKDH was run on morpholine citrate (PH 6.1) and lithium borate (PH 8.3). The most variable isozymes were MDH and 6PGD. MDH and 6PGD revealed 10 and 9 bands, respectively. This study showed that isozyme variability exists in roses and can be useful in their classification into species groups.
Abstract
Burrknot development on the aboveground portion of apple (Malus sp.) rootstocks Mailing Merton (MM) 111 and MM 106 was arrested effectively by direct application of a commercial, emulsified formulation of 2,4-xylenol and m-cresol plus 3 organic penetrants. M-cresol in mineral oil at 1.5% (v/v) was as effective as the commercial formulation in killing the burrknot tissue. Covering untreated burrknots with soil allowed complete rooting from the burrknot within 6 months.
Abstract
Available young hybrid trees of Eremocitrus glauca with ‘Valencia’ orange (Citrus sinensis (L.) Osbeck), Sicilian sour orange (C. aurantium L.), ‘Nagami’ kumquat (Fortunella margarita (Lour.) Swing.), and Koethen sweet orange (C. sinensis) were more cold hardy than the Citrus or kumquat parent in natural and controlled freezes. Eremocitrus may be a useful source of cold hardiness for breeding cold-hardy citrus hybrids.
Abstract
Zn content was higher in trunk bark (cambium to outer scrapings) than in the adjacent wood in healthy and blight-affected sweet orange (Citrus sinensis (L.) Osb.) and grapefruit (C. paradisi MacF.) trees. Zn levels were elevated in trunk bark and wood of blight-affected trees on rough lemon (C. limon (L.) Burnt, f.) rootstock, whereas affected seedling trees or trees on ‘Cleopatra’ mandarin (C. reticulata Blanco) rootstock that were tested had high Zn levels only in the bark. Bark Zn content was much higher above the bud union than below in blight affected trees on rough lemon or trifoliate (Poncirus trifoliata (L.) Raf.) rootstocks, but Zn content was high above the bud union in healthy trees only on rough lemon rootstock. The inner half of the bark, an area representative of the active secondary phloem, had much more Zn than the outer half of the bark or the most recently developed xylem. The outer half of the bark served as a barrier against outside contamination. Accumulation of Zn in wood occurred only when the phloem Zn was high.
Abstract
14C-Ethylene was the major breakdown product of 1,214C-(2-chloroethyl)phosphonic acid (ethephon)-treated fruit and leaves of several Citrus taxons. Neither 14CO2 nor other by-products were detected. Most of the nonethylene radioactivity recovered was from tissue surfaces. Radioactivity was not readily translocated from leaves or fruit.
Abstract
Sweet orange cultivars, Citrus sinensis (L.) Osbeck, in several stages of blight (young tree decline) were studied for characteristics of waterflow or uptake. Many small and major roots and the trunk on moderately blighted trees had restricted waterflow or uptake capabilities. Some small and major roots on the blighted side of early-stage or sectored trees also had restricted waterflow or uptake capabilities, but the healthy side roots functioned similarly to those on healthy trees. Dye uptake patterns confirmed that the waterflow or uptake was restricted in the diseased portions of the trees. On moderately blighted trees, young xylem appeared to be more functional for water movement than older xylem. Necrotic roots were found on the blighted side of early-stage sectored trees and moderately blighted trees, but not on the healthy side of sectored trees or on healthy trees. The sectoring type of early blight expression affords a model system for study whereby both blighted and apparently healthy tissues occur on the same tree.
Abstract
Fertilization of field grown roses, R. hybrida cv. Christian Dior, in south Florida with fertilizer packets and tablets was compared with a proven plastic mulch method of reducing fertilizer losses. Flower yields for the 3 methods were similar during the first 9 months of the study. In the second year, comparatively low yields were obtained with tablets, and the highest yields with the plastic mulch. The packets gave intermediate results, with 5 packets providing acceptable yields. Twenty-one months after placement, the tablets contained 56, 56, and less than 0.1% of their original N, P, and K, respectively. Nitrogen release at this time appeared comparatively slow. Considerable variation in nutrient content existed among packets 21 months after placement, with an average of 17, 33, and 38% of the original N, P, and K, respectively, being found. The packets still appeared to be releasing fertilizer at that time.
Abstract
The flesh of ‘Redblush’ grapefruit exposed to 41.8°C day/36.1°C night temperatures in environmental growth chambers for 60 days did not increase in lycopene content, while fruit exposed to natural conditions in sunlight and under shade did. Lowering the temperature from 41.8°C/36.1°C to 32.2°C/21.1°C produce a high level of lycopene. Carotene concns. of fruit exposed to 41.8°C/36.1°C and natural conditions remained the same. Exposure to 32.2°C/21.1°C caused a small increase in carotene, while exposure to natural conditions, at lower temperatures, caused a larger increase in carotene.
Abstract
Orange trees (Citrus sinensis (L.) Osb.) with early-stage (sectored) and moderate blight were evaluated for zinc accumulation and water translocation characteristics. Zinc accumulated at above-normal levels in the outer 2 cm of trunk wood, but water uptake was at below-normal levels in the inner 2 to 6 cm of trunk wood of moderately blighted trees. Water-flux density of roots was not correlated with zinc accumulation. In trees with early stages of blight, zinc accumulated at above-normal levels in the healthy-appearing sides of the trunks, as well as in the blighted sides, but the water uptake in the healthy-appearing sides was similar to that in the trunks of healthy trees. Evidence suggested that the blight effect on abnormal zinc metabolism developed prior to the dysfunction of water translocation.