Produção de sementes sintéticas de maracujazeiro silvestre com potencial ornamental

Passiflora cincinnata is a wild species of passion fruit with a wide geographical distribution. It has vigorous growth, climbing habit and very showy and fragrant flowers. The aim of the present investigation was to obtain synthetic seeds from encapsulated zygotic and somatic embryos of P. cincinnata, cultivated under different conditions. Precotyledonary and cotyledonary stage embryos were obtained from zygotic embryos cultivated on MS medium supplemented with 18.1 μM of 2,4-Acid-dichlorophenoxyacetic (2,4-D) and 4.5 μM of Benzyladenine (BA). Zygotic embryos and somatic embryos stages were encapsulated using sodium alginate (2.5% w v-1) and CaCl2.2H2O (1 mM) as complexing agent. The zygotic and somatic embryos were encapsulated in a matrix containing (I) sodium alginate, (II) sodium alginate + artificial endosperm and (III) sodium alginate + artificial endosperm supplemented with activated charcoal (0.15% w/v). Zygotic embryos encapsulated in the matrix (I), matrix (II) and matrix (III) and cultivated in flasks, germinated at rates of 79%, 76% and 86% respectively. The cotyledonary somatic embryos encapsulated in the 3 different matrices showed better germination rates when cultivated on cellulose plugs, with more than 50% of embryos converted into plants. Precotyledonary somatic embryos did not germinated regardless the matrix and cultivation. When cultivating the alginate beads ex vitro, both substrate Plantmax and Florialite showed low number of germinated embryos, and the best result (12.67%) were obtained using Florialite and embryos encapsulated in the matrix (I).

Prevention of shoot vitrification of strawberry micropropagated shoots proliferated on liquid media by new antivitrifying agents

Micropropagated strawberry (Fragaria × ananassa Duch. ’Kent.’) cultured for 4 wk in liquid proliferation media supported on cellulose plugs (sorbarods) developed a high rate of vitrification. This high percentage of abnormal plantlets was significantly reduced by the inclusion of two antivitrifying agents, EM1 and EM2, to the liquid medium. Virtually no vitrification occurred at 5 g L−1of EM1 or EM2. Shoots multiplied on liquid medium supplemented with 5 g L−1 of either EM1 or EM2 had significantly lower fresh weights and lower multiplication rates than on solidified agar medium (0.7%). EM2 produced better growth and proliferation than EM1 or liquid medium alone and was easier to use than EM1. Key words: Vitrification, antivitrifying agent, liquid medium

Paclobutrazol and Reduced Humidity Improve Resistance to Wilting of Micropropagated Grapevine

Plantlets of Vitis vinifera L. `Moscato Bianco' were grown in vitro in cellulose plugs (Sorbarods) saturated with a modified Murashige and Skoog rooting medium. Both the inclusion of 0.5-l mg paclobutrazol/liter in the rooting medium and the use of culture vessels that reduce the relative humidity from 100% to 94% improved resistance of plantlets to wilting after transplanting. Maximum benefit was obtained with a combination of paclobutrazol and reduced humidity; it resulted in smaller stomatal apertures, shorter stems, reduced leaf area, and more and thicker roots. Chemical names used: (2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl) pentan-3-01 (paclobutrazol).