Estabelecimento e multiplicação in vitro de porta-enxertos de Prunus

Abstract

RESUMO -A qualidade genética e sanitária das mudas é de fundamental importância para o sucesso da fruticultura moderna. Para o pessegueiro, a micropropagação vem permitindo a produção clonal massal de plantas, com matrizes e mudas de qualidade genética-sanitária comprovada. O presente trabalho objetivou avaliar a taxa de sobrevivência de explantes no estabelecimento in vitro, bem como avaliar o potencial de multiplicação in vitro de porta-enxertos de Prunus. Explantes constituídos por ápices caulinares e gemas laterais dos porta-enxertos Capdeboscq e GF677 e da seleção VP411 foram estabelecidos e multiplicados in vitro em meio de cultura de Lepoivre suplementado com BAP (0,5 mg.L -1 ). A taxa média de sobrevivência para os porta-enxertos foi 62,9% para ápices caulinares e 58,8% para gemas laterais. Ápices caulinares e gemas laterais apresentaram 14,8% e 29,8% de contaminação, respectivamente. O genótipo afetou significativamente as taxas de multiplicação in vitro. Quanto ao número de brotos por explantes, o porta-enxerto Capdeboscq e a seleção VP411 foram superiores ao porta-enxerto GF677, resultando em 14,7; 16,0 e 10,5 brotos, respectivamente. Para a altura média dos brotos, os porta-enxertos Capdeboscq e GF677 foram superiores à seleção VP411 com 9,3; 8,9 e 7,8 mm, respectivamente. O portaenxerto Capdeboscq foi superior ao porta-enxerto GF677 e à seleção VP411 na variável número de brotos >20 mm com 2,0; 1,3 e 1,0 brotos, respectivamente. Termos para indexação: Pessegueiro, porta-enxertos, BAP, micropropagação, mudas. IN VITRO ESTABLISHMENT AND MULTIPLICATION OF PRUNUS ROOTSTOCKSABSTRACT -The success of the modern fruit production depend on the genetic and sanitary quality of plants. For the peach tree culture, micropropagation techniques allow a mass clonal production with high genetic quality plants. The present study aimed to evaluate the explant survival rate during in vitro establishment period, as well as to evaluate the in vitro multiplication potential of Prunus rootstocks. Apexes and lateral buds of the rootstocks Capdeboscq and GF677 and of the selection VP411 were introduced in vitro in the Lepoivre's medium supplemented with BAP (0.5mg.L -1). The mean values of explant survival for the rootstocks were 62.9% and 58.8%, for apexes and lateral buds, respectively. Cultures of apexes and lateral buds showed 14.8% and 29.8% of contamination, respectively. The genotype significantly affected the in vitro multiplication rates. The rootstocks Capdeboscq and GF677, and the selection VP411 showed multiplication rates of 14.7, 10.5 and 16.0 shoots/explant, respectively. As mean values for shoot height of the rootstocks Capdeboscq and GF677 and of the selection VP411, it was observed 9.3, 8.9 and 7.8 mm, respectively. The rootstock Capdeboscq showed superior values as regarded to the number of shoots >20mm as compared to rootstock GF677 and selection VP411 with values of 2.0, 1.3 and 1.0 of shoots, respectively.

Morphological and physiological photon flux influence under in vitro culture of apple shoots

“…There was a reduction of this parameter only when the cultures were exposed to a higher photon flux density (60 µmol m -2 s -1 ). Considering that in vitro responses were dependent on the genotype (Silva et al, 2003), the best results obtained (between 13.54 and 17.09 shoots per explant) were similar to those reported by Schuch and Peters (1993) that obtained 19.13 and 16.07 shoots per explant in Marubakaido and Megumi apple rootstocks, respectively. As could be observed in Table 1, the shootings length was influenced by the photon flux density and by the culture media (Fig.…”

“…Marubakaido, did not observe significant effect regarding sucrose concentrations, although 45 g L -1 allowed a higher mean growth of the shoots. As pointed out in relation to the number of shootings, in vitro growth was also dependent on the genotype (Silva et al, 2003). Regarding the number of leaves per shooting (Table 2), it was observed that the treatment with 14 µmol m -2 s -1 was statistically higher than the other treatments, with a significant reduction when used 60 µmol m -2 s -1 , in spite of the culture medium used.…”

“…Similar results were obtained by Gürel and Gülsen (1998), studying in vitro production of shoots of Amygdalus communis, highlighting though that 20 g L -1 of sucrose determined lower number of shoots per explant. Silva et al (2003) observed a high rate of multiplication in Prunus, with 20 g L -1 of sucrose. In the present work high multiplication rate (number of shoots per explant) was observed, independent of the medium used (Table 1).…”

In vitro multiplication of 'Flordaguard' rootstock: cytokinin source and concentration effects, explants orientation and period of permanence in the culture medium

“…The plant effects are characterized, mainly, for the lack of explants growth, leaves size reduction, internodes shortening, stems thickening and general hyperhydricity, which conduce to a serious problem in the rooting phase . Several works have been made with Prunus species using different BAP concentrations, varying from 0.1 to 6.0 mg L -1 , confirming the efficiency of this plant growth regulator, which can change according to species or cultivar (Reeves et al, 1983;Parffit and Amehdi, 1986;Silva et al, 2003;Wagner et al, 2003;Teixeira et al, 2004). Another factor that can also contribute significantly for the success during the multiplication phase is the explants orientation (Yae et al, 1997).…”

Micropropagação de pequizeiro (Caryocar brasiliense Camb.)

“…Ao final deste período, observou-se a porcentagem de plantas vivas em função dos tratamentos aos quais as plantas foram submetidas na fase de enraizamento. (Silva et al, 2003). As pequenas variações nas respostas obtidas decorrem, certamente, do balanço interno de cada planta, bem como da competência de cada tipo de explante para desenvolver a resposta morfogenética.…”