Flávia Dionísio Pereira

Phosphate solubilization and phytohormone production by endophytic and rhizosphere Trichoderma isolates of guanandi (Calophyllum brasiliense Cambess)

This work aimed to isolate and evaluate the phosphate solubilization and phytohormone production abilities of endophytic and rhizosphere fungi belonging to the genus Trichoderma isolated from guanandi (Calophyllum brasiliense Cambess). From the guanandi collected from the field, 12 isolates obtained were grown in potato dextrose broth and supplemented with the phosphate sources, to test their capacity to solubilize phosphates. A strain of Trichoderma asperellum from a commercial inoculant was also used. One isolate was able to solubilize calcium phosphate, 12 solubilized iron phosphate and two solubilized aluminum phosphate. Only the rhizosphere isolates were able to synthesize indole acetic acid (IAA) and none of the rhizosphere or endophytic isolates produced cytokinin or gibberellin. There are Trichoderma isolates that can benefit plant development, both for their known antagonistic ability against phytopathogenic fungi and for their ability to provide phosphates and or to produce phytohormones. Key words: Trichoderma, inoculants, calcium, iron, aluminum, solubilization, plant growth promotion.

In vitro cultivation of Anacardium othonianum Rizz.: Effects of growth regulator, explant orientation and lighting

Anacardium othonianum Rizz. is a Brazilian savannah native species, commonly known as caju-dearvore- do-cerrado. Its usual reproduction is by seeds or asexually; however, its use in forest programs or for commercial orchards demands continuous and large scale seedling production. This study evaluated the effect of naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP), the position of the explants and the effect of lighting in the regeneration of A. othonianum Rizz. stem segments. The Murashige and Skoog medium (MS) medium was used in the first test, amended with nine combinations of NAA (0, 5.37 and 10.74 μM) and BAP (0, 4.44 and 8.88 μM) in a completely randomized design. While the second test was arranged as a 2 × 2 factorial, evaluating the orientation of the explants (upright or horizontal) and incubation condition (absence or presence of light). The number of buds, the number and average length of leaves and the number of plantlets were evaluated after 30 and 60 days of growth. The results obtained indicate that the concentrations of BAP and NAA used had no effect on the multiplication of A. othonianum Rizz. stem segments, and the best morpho-physiologic in vitro response was obtained with horizontal segments in the presence of light. Key words : Growth medium, micropropagation, savannah plants.

Alternative tube caps on in vitro growth of Orbignya oleifera Burret.: An Arecaceae native cerrado domain

The babassu ( Orbignya oleifera Burret) is a palm that contains oilseeds whose biomass can be used for biofuel production. Due to difficulties in germinating the species, in vitro cultivation techniques are sought as a viable alternative to expand studies on germination. The objective of this study was to evaluate different types of tube caps for in vitro growth of babassu seedlings. Thus, zygotic embryos were inoculated in tubes containing MS medium with a 50% salt concentration, which were sealed with diferent caps, a cotton plug, plastic cap, PVC film and plastic cap with PVC film. During the in vitro culture, the mean length of seedlings, the formation of the cotyledon petiole and root, as well as oxidation of the explants were evaluated. The cotton plug exhibited a positive effect on the initial steps of in vitro cultivation, which promoted more vigorous plants with greater mean lengths; however, its effect decreased as the cultivation time increased. The cotton plug is an alternative and eight-fold less expensive than a conventional plug, which favors early in vitro growth of O. oleifera Burret. Key words : Babassu, Goias Cerrado, tissue culture.