Micropropagation of Two Tropical Conifers: Pinus Oocarpa Schiede and Cupressus Lusitanica Miller

The tissue culture response of embryo explants of four fast-and slow-growing provenances of Pinus caribaea var. hondurensis was investigated. Treatments included adventitious bud induction and development with benzyladenine (BA) at different concentrations and exposure periods, root induction with naphthaleneacetic acid (NAA) and indolebutyric acid (IBA) and callus production with combinations of NAA, 2, 4-dichlorophenoxyacetic acid (2, 4-D), BA and kinetin. Fast-growing provenances produced nodules earlier on the cotyledonary surface, developed shoots earlier from induced buds and produced more shoots per surviving embryo at lower BA concentrations tested compared with slow-growing provenances. On the other hand, calluses of the slow-growing provenance, La Mosquitia, grew faster on media supplemented with cytokinins and auxins compared with those grown on media supplemented with auxin only. This reaction was not observed with fast-growing provenances. It is suggested that cytokinins in fast-growing provenances promoted organized development more efficiently than in slow-growing provenances.

Section: Embryo Culturementioning

confidence: 99%

Section: Embryo Culturementioning

confidence: 99%

In vitro response of embryos from different provenances of Pinus caribaea var. hondurensis Morelet

Perez-Orozeo

Halos

1993

“…The excised embryos were cultured on a basal medium consisting of a modified Murashige and Skoog Medium (MSM) (Franco & Schwarz 1985) supplemented with 3% sucrose, 0.5% Phytagar (GIBCO) and 8.9, 22.2, 44.4, or 67.7 IxM BA. Exposure times were 1, 2 and 3 weeks after which the embryos were transferred to either full-or half-strength MSM supplemented with 2% sucrose.…”

Section: Culture Conditionsmentioning

confidence: 99%

“…Root formation was induced in full-strength Cupressus Basal medium (CBM) (Franco & Schwarz 1985) supplemented with 1% sucrose, 0.35% Phytagar and auxins (1 IxM NAA, 0.5 txM NAA, 100 ixM NAA, 1 txM NAA + 10 ixM IBA, or 101xM IBA). Shoots were exposed to the different auxin concentrations for 2 weeks except for those treated with 100 ixM NAA, which were pulsed for 24 h. After the root induction period the shoots were transferred to half-strength modified Gresshoff and Doy Medium (GDM) (Franco & Schwarz 1985) with 1% sucrose for root elongation. Using i-week exposure to 1 IxM NAA as the auxin treatment, the effects of different levels of sucrose, and organic additives (glyphosate and coconut water) on root formation were also investigated.…”

Section: Culture Conditionsmentioning

confidence: 99%

Micropropagation of Pinus caribaea Morelet

Halos

1993

Adventitious shoot formation was induced in excised mature embryos of Pinus caribaea using a modified Murashige and Skoog medium (MSM) supplemented with 6-benzyladenine. The highest frequency (96%) of adventitious bud production was observed when embryos were exposed to 8.9 ~M BA for one week prior to transfer to a growth regulator-free medium. Increased BA concentration and longer exposure to BA significantly reduced survival rates of explants. Dilution of the basal medium to 1/4x and 1/8x decreased shoot formation but 1/2x was just as effective as full-strength. Addition of auxins, glyphosate and coconut water to the rooting medium did not improve rooting success beyond that of spontaneous rooting. Sucrose at 1.5% significantly increased rooting of shoots. Plantlets were successfully transferred to the soil after preincubation in liquid medium.

“…Franco & Schwarz [7], use nutrient media which are gelled with agar so that the solid media may act as supports for the explants. However, the presence of the agar inhibits regular and non-destructive sampling, and replenishing, of the nutrients in the medium.…”

Section: Introductionmentioning

confidence: 99%

In vitro culture of shoots of Pinus caribaea on a liquid medium

Skidmore

Simons

Bedi

1988

Shoot apices of a clone of Pinus caribaea Morelet were cultured and multiplied in vitro by supporting them with their basal cut ends immersed in a liquid nutrient medium.The initial heights of explants and their initial numbers of leaves were positively correlated with the numbers of buds and shoots produced by the explants after a bud induction phase and after a shoot elongation phase. The final numbers of buds and shoots were positively correlated with reductions in the quantities of phosphorus detected in the media and negatively correlated with the numbers of brown leaves produced on the explants.In a comparison between the growth of shoot explants on liquid and solid media, shoots incubated on the liquid medium showed significantly greater increases in length in a four-week period than those cultured on solid medium. This technique, using liquid media, provides a system in which both the nutrient utilization and the growth rates of isolated pine tissues can be readily assessed. Furthermore, the multiplication rate of the tissue can be predicted following the observation of correlated characters early in the micropropagation cycle.