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  • Author or Editor: N. Zieslin x
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Abstract

The commercial formulation of grafting adhesive is based on cyanoacrylate as an active ingredient with a proper solvent and catalyzer. Before grafting, the upper 5-10 mm of the stock are removed transversally. A similar cut should be made at the basal part of the scion. There is no need for drying the cut-surface: a wet surface will accelerate the graft union. A minimal amount of adhesive should be squeezed from the tube on the outer ring (cortex) of the cut without covering the central core (Fig. 1). For convenience, covering the basal part of the scion with the adhesive is preferable. Vascular differentiation, however, will take place even though the graft surface to surface connection is incomplete (2). The stock and scion cut surfaces should be held together for 5-7 seconds to complete the graft.

Open Access
Authors: and

Abstract

An inverse correlation between number of roots regenerated and diameter of root segments (except fibrous roots) was found in Rosa ⨯ Noisettiana cv. Manettii. Length of regenerated roots was proportional to the diameter of root segments. The root-regenerating potential varied among scion cultivars. Manetti root segments regenerated best with rose scion cultivar ‘Cara Mia’, and least with ‘Golden Wave’.

Open Access
Authors: and

Abstract

The causes for petal blackening of ‘Baccara’ rose petals and the differences between normal (red) and black flowers were investigated. Black flowers are frequent in field grown plants and dark red ones in those grown in unheated greenhouses during the winter. Two anthocyanins were isolated and identified: cyanidin 3,5-diglucoside (cyanin) and pelargonidin 3,5-diglucoside. The 2 pigments were found in both red and black petals. The content of both anthocyanin pigments as well as that of tannins, was several times higher in black flowers than in normal flowers. High polyphenolase activity was found in black petals, while no activity could be detected in normal red flowers. The blackening phenomenon is attributed to an increase in anthocyanin content at low temperatures, and to the accumulation of oxidation products of polyphenols.

Open Access
Authors: , , and

Abstract

Four rose cultivars (‘Mercedes’, ‘Sonia’, ‘Visa’, and ‘Golden Times’) were grown under four night temperature regimes: 1) constant 18°C; 2) constant 14°; 3) 18° until midnight followed by 14° until 1 hr before sunrise; and 4) 18° alternated every 2 hr by 14°. A minimal temperature of 18° was maintained from 1 hr before sunrise in all treatments. Low temperature regimes resulted in an increase in the time period required for flower development and the number of flowers produced was lowest under the constant low temperature regime. The number of flowers produced under the two partial heating regimes was similar to the constant high temperature in 3 of the cultivars examined. Alternating the temperature every 2 hr stimulated the flower production of ‘Golden Times’. Under this regime, 28% more flowers were produced in comparison to a constant temperature of 18°.

Open Access

Abstract

The flower yield of glasshouse roses is made up of 3 components: number of flowers appearing in the upper buds of the branches, number of flowering branches from the plant, and number of flowers appearing on ‘other’ parts of the plant. The number of flowers produced is the product of the number of buds sprouted times the percentage that flower. Flowering potential of the uppermost bud on a branch is greater and the rate of flower abortion (“blindness”) is less, than of buds produced lower on the branch Reduction in yield found during winter in cv. Baccara was mainly due to “blindness” of the uppermost bud. ‘Marimba’ was more productive than ‘Baccara’ due to a larger number of both flowers per branch and flowering branches per plant. The productivity of ‘Baccara’ when grafted on R. indica was greater than that of ungrafted plants because of the greater number of flowering branches produced on grafted plants.

Open Access

Abstract

One year old ‘Baccara’ roses budded on Rosa chinensis cv. ‘Major’ were planted in large containers and irrigated for 90 days with water containing various salinity levels (ca. 0.4 to 7.8 EC × 103). Salinization was obtained by either chloride or nitrate salts. Irrigation with water containing chlorides was more detrimental than with water containing nitrates at the same level of salinity. Stem and leaf growth and water uptake decreased with increasing soil salinity. A slight decrease was noticed even at 2.0 mmhos/cm, containing chlorides, the damage increasing with time, indicating a cumulative effect of soil salinity even at low salinity level.

Open Access

Abstract

Flowers of different cultivars of rose (Rosa hybrida L.) vary in their sensitivity to bent-neck after cutting with ‘Cara Mia’ the most sensitive, and ‘Samantha’ the most resistant of the cultivars tested. Bent-neck is influenced by several factors: water loss by leaves, differences in water uptake ability of the stem, and the ability of the bloom to absorb water from other plant organs on the flower shoot.

Open Access

Abstract

Spary treatment of (2-choroethyl)phosphonic acid (ethephon) on the lower, unleafy parts of rose plants promoted the formation of renewal canes (growth of basal shoots). The best response was in the cv. Baccara. A thin score above the bud with a saw blade dipped in ethephon greatly increased the efficiency of the treatment.

Open Access