Frank A. Blazich

Nitrogen nutrition of hedged stock plants of Loblolly Pine. II. Influence of carbohydrate and nitrogen status on adventitious rooting of stem cuttings

Hedged stock plants of four full-sib families [27-2 × 27-5, 27-3× 27-1, 27-2 × 27-1, and 27-6 × 27-1 (designated B, G, R, andW)] of loblolly pine (Pinus taeda L.) were fertilizeddailywith a complete nutrient solution containing N at either 10, 25, 40, 55, or 70mg·L−1. May (spring softwood), July(summersoftwood), and January (winter hardwood) terminal stem cuttings were taken fortissue analysis and rooting studies. Spring cuttings rooted in the highestpercentages (59.5%), followed by winter (40.5%), and summer (34.7%). Maximumrooting for spring (70.0%), summer (48.6%), and winter (55.6%) occurred withcuttings taken from hedges that received N at 55mg·L−1. Genetic differences among familieswere evident as families G and W rooted in greater percentages at lower appliedN rates and family B was the best rooting family at the highest applied N rate.When internal N levels were considered families G and W also rooted best at lowinternal N levels, while family B was the best rooting family at high internalNlevels. Neither total nonstructural carbohydrates (TNC) nor any of severalspecific carbohydrates were correlated with rooting and an optimal TNC : Nratiofor rooting was not found. Root counts generally increased with increases inapplied N. Root number was weakly correlated with TNC (R = 0.29, P ≤0.01) and several specific sugars, but was not correlated with internal N.Totalroot dry weight, total root length, and total root area responded similarly.

Nitrogen nutrition of hedged stock plants of Loblolly Pine. I. Tissue nitrogen concentrations and carbohydrate status

Hedged stock plants of four full-sib families [27-2 × 27-5, 27-3× 27-1, 27-2 × 27-1, and 27-6 × 27-1 (designated B, G, R, andW)] of loblolly pine (Pinus taeda) were fertilized dailywith a complete nutrient solution containing N supplied fromNH4NO3 at either 10, 25, 40, 55, or 70mg·L−1. In May (spring softwood), July(summer softwood), and January (winter hardwood) terminal stem cuttings weretaken for tissue analysis and rooting studies. Averaged over families, meantissue concentrations of N were higher in spring (1.8%) and summer (1.7%) thanin winter (1.3%). Concentrations of N increased linearly with increasing levelsof applied N. Concentrations of total nonstructural carbohydrates (TNC) inwinter (32.8%) were twice those in spring (17.1%) or summer (16.3%), but wererelatively unaffected by N application. In contrast, starch concentrations weresignificantly higher during spring and summer than winter. The greatest numbersof orthotropic shoots ≥ 9 cm in length were produced for thespring, followed by summer, and then winter hedgings. Number of shoots producedper hedge increased with increasing applied N rates, and family B producedsignificantly more shoots than the other three families at all applied N levels.Genetic differences among families were evident as several interactions with Nrates were observed.

Abies fraseri (Pursh) Poir. (Fraser Fir)

The genus Abies Mill. (firs) is one of the largest in the Pinaceae (Krussman 1985). Liu (1971) provided a taxonomic monograph of the genus Abies, and reported that it included two subgenera with 15 sections composed of 39 species, 27 varieties, and 9 hybrids. The genus was characterized morphologically by: (1) a peculiar resin commonly termed balsam, (2) buds on lateral branches often arranged hastately, (3) branchlets marked with circular disk-like leaf scars, (4) solitary male flowers (the genus is monecious) having short horizontal knob-like projections at the posterior portion of stamens and their anthers opening by a transverse slit, (5) erect and often variously colored cones with thin cone scales and bract scales separating from the cone axis upon seed maturity, and (6) seeds having resin vescicles infolded by the lower part of their thin wings. The wood consists only of tracheids and rays without normal resin canals. The tracheids have bordered, taxodioid pits.

Floral foam and/or conventional or organic preservatives affect the vase-life and quality of cut rose (Rosa × hybrida L.) stems

Summary We studied the effects of floral foam (Oasis®), with or without conventional or organic preservatives, to determine the optimum treatment to extend the vase-life of the cut rose (Rosa × hybrida L.) cultivars ‘Freedom’ and ‘Charlotte’. In general, floral foam resulted in similar or reduced vase-lives in cut ‘Freedom’ and ‘Charlotte’ rose, and had no influence on the symptoms of senescence in either cultivar. ‘Freedom’ showed more petal browning and rot, as well as reduced flower bud opening, compared to ‘Charlotte’. Vase solutions containing either of two conventional preservatives resulted in longer vase-lives in the stems of both cultivars than stems in deionised (DI) water. Floral foam saturated with DI water resulted in greater changes in the pH of the vase solution in both cultivars. Among the preservatives tested, conventional products such as Floralife Premium Rose Food or Chrysal Rose Vase (each at 10 ml l–1) extended the vase-life by 5.5 d or 3.9 d, respectively; whereas organic products such as Vita Flora or Vita One Step (each at 0.53 ml l–1) resulted in statistically similar vase-lives (9.3 d or 8.3 d, respectively) as stems in DI water (7.5 d), irrespective of the use of floral foam. These findings suggest that floral foam should not be used during the post-harvest handling of cut rose stems. Moreover, conventional preservatives were more effective than the organic products.

Postharvest performance of cut carnation, chrysanthemum and rose as influenced by conventional and organic floral preservatives

Selected commercial preservatives were tested to determine the optimum conventional and organic hydrator and holding solutions for vase life extension and suppression of microbial populations in vase solutions of cut carnation (Dianthus caryophyllus L.) Select Red, chrysanthemum [Dendranthemum grandiflora (Ramat.) Kitam.] Anastasia, and rose (Rosa × hybrida L.) Freedom. Hydrators extended vase life of carnation but had no effect on chrysanthemum or rose. Chrysal Professional 2 (conventional holding solution), after hydration with deionized (DI) water, extended vase life of cut carnation to 36.0 days compared with DI water or Vita One Step (organic preservative solution), resulting in vase lives of 21.0 or 20.9 days, respectively. For chrysanthemum, all preservative solutions had statistically similar vase life. Holding solutions increased vase life of cut roses and carnation, but were ineffective for chrysanthemum. The greatest vase life extension occurred with Floralife Premium Rose Food (conventional holding solution), 7.9 and 7.3 days longer, than with DI water in cut Freedom roses after treatment with Floralife Hydraflor 100 (conventional hydrator solution) and DI water, respectively. However, Vita One Step (organic hydrator and holding solution) reduced vase life by 2.4 days and had higher bent neck incidence (93%) than DI water. Floralife Premium Rose Food and Chrysal Rose Vase (conventional holding solution) effectively controlled bent neck. DI water with organic Vita products had higher bacterial populations than conventional products for all species tested. Among the preservatives investigated, conventional products increased vase life more than organic products, indicating the need for organic preservatives with effective antimicrobial activity.