Tannins in the fungi inhibition and the seed germination of Pinus taeda L.
Name: HERNESISE MAYARD
Publication date: 29/07/2020
Advisor:
Name |
Role |
|---|---|
| FABRICIO GOMES GONÇALVES | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| FABRICIO GOMES GONÇALVES | Advisor * |
| JUAREZ BENIGNO PAES | Internal Examiner * |
Summary: Tannins are complex polyphenols known to have antimicrobial and antifungal properties and also prevent seeds from germination early, as well as protecting them from pest attack, thus being used in plant defense, and having negative effects on predators in seeds. The objective of this work was to analyze commercial tannins from Acacia mearnsii De Wild., inhibition of fungi and germination of Pinus taeda L. seeds. In Chapter I, two experiments were carried out: Experiment I: identification of possible fungi in commercial nursery substrate WHERE soil samples were placed in sterilized petri dishes and moistened with water distilled and sterilized for sowing (80% of field
capacity). Then, eucalyptus leaves were placed on the ground with small holes. The plates were kept in biochemical oxygen demand camera (BOD) at 25 ºC until the appearance of fruiting of possible fungi. The fungi were seeded in a Petri dish containing approximately 10 mL of potato dextrose agar (PDA) culture medium. These were incubated in BOD at a temperature of 25 ºC with a photoperiod of 12 hours until obtaining pure colonies; Experiment II: were used six tannin concentrations (0; 4; 8; 12; 16 and 20%) diluted in distilled water. Four fungi (Pythium spp., Penicillium sp, Fusarium sp. and Rhysopus spp.) and P. taeda seeds were used with three repetitions of 12 seeds per repetition for each fungus, plus the control. First, the seeds were disinfected and soaked in the tannin concentrations for 10 minutes. Next, 10 mL of PDA
previously prepared and kept in BOD for 15 days were placed in a petri dish.
Experiment III: it was idealized in experiment II, the concentration of 20% tannin was applied plus a control (without the presence of tannin), and these were placed together with the fungi Fusarium sp., Penicillium sp., Pythium spp. and Rhizopus spp. Two replications were used, 80 seeds per repetition, totaling 160 seeds per treatment. A batch of 160 seeds was embedded in the tannic solution and distributed in Petri dishes, along with the fungus. The fungi Rhizopus spp. and Fusarium sp. are the ones that develop faster during the experiment. The tannin reduced the development of the tested fungi with increased concentrations. With the use of tannin the seeds germinate more in
the presence of the fungus. In Chapter II, four basic experiments were carried out (tetrazolium test, electrical conductivity, imbibition curve and germination test with evaluation of seedling quality parameters). A completely randomized design was applied, consisting of six concentrations of tannins (0; 4; 8; 12; 16 and 20%) with four repetitions of 25 seeds. A batch of 100 seeds was soaked in each concentration for a period of 10 minutes and placed on a paper roll and kept in the BOD to germinate at a temperature of 25 ºC. According to the tetrazolium test, the seeds have a viability of 75%. In electrical conductivity, higher concentrations provide greater results. The imbibition curve follows the three-phase pattern. The quality characteristics of the seedlings showed results of varied tendencies as the tannin concentration increased. There were highlights of increase, or shoot length and neck diameter. A percentage of
germination, normal seedlings and deterioration of the seed show a falling behavior with increased tannin concentration.
Keywords: Acacia mearnsii; microorganisms; physiological seed quality; polyphenols.
