Growth retardants on development and ornamental quality of potted 'Lilliput' Zinnia elegans Jacq.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of daminozide, paclobutrazol and chlormequat on development and quality of potted 'persian carpet' zinnia

In Brazil zinnias have good prospect for the flowering potted plant market, once consumers demand for new forms of products is stimulated by novelty. 'Persian Carpet' is a highly ornamental plant, with fast growth, minimal labor requirements and low cost seeds. The present study evaluated the effect of growth regulators on development and quality of 'Persian Carpet' grown as a potted plant. Growth regulators are commonly used to control growth and produce short and compact plants. Paclobutrazol (0.5, 0.75 and 1.0 mg a.i./pot) and chlormequat (1.0, 2.0 and 3.0 g. L-1) were applied as a single drench, and daminozide (2.5, 3.75 and 5.0 g. L-1) as a single foliar spray to runoff. Regulators were applied at apical flower bud stage. Daminozide (5.0 g. L-1), paclobutrazol (0.5, 0.75 and 1.0 mg a.i./pot) and chlormequat (1.0 g. L-1) significantly reduced plant height and side branches length compared to the control. Plant height showed a negative linear response to the increasing concentration of daminozide or paclobutrazol. Paclobutrazol (1.0 mg a.i./pot) and chlormequat (1.0 g. L-1) increased foliage and flowers harvest index. Plant spread diameter and canopy shape were improved with paclobutrazol (0.75 mg a.i./pot). Chlormequat (2.0 and 3.0 g. L-1) caused phytotoxicity symptoms, turning plants unsuitable for commercialization. Studied regulators concentrations did not affect flower diameter and production cycle. Although regulators controlled height and side branches growth significantly, plants were not short and compact enough to attend market quality.

Towards the development of fiber lasers for the 2 to 4 nanom spectral region

A growing number of applications are calling for compact laser sources operating in the mid-infrared spectral region. A review of our recent work on monolithic fiber lasers (FL) based either on the use of rare-earth fluoride fibers or on Raman gain in both fluoride and chalcogenide glass fibers is presented. Accordingly, an erbium-doped double clad fluoride glass all-FL operating in the vicinity of 3 μm is shown. In addition, we present recent results on the first demonstrations of both fluoride and chalcogenide Raman fiber lasers operating at 2.23 and 3.34 μm, respectively. It is shown that based on this approach, monolithic FLs could be developed to cover the whole 2 to 4 μm spectral band.