Abstract Detail

Physiology & Ecophysiology

Köhler, Matias [1], Soares, Geraldo Luis Gonçalves [2].

Small seeds are more sensitive to phytotoxic effects of an essential oil during germination.

Extant angiosperms have a great variety of seed masses, spanning 11 orders of magnitude, from the dust seeds of orchids up to the 20 kg seeds of the double coconut. These characteristics is an important functional trait in plant ecology with real implications on germination. In this study, we investigated how this attribute may be related to susceptibility to a phytotoxic essential oil during seed germination. Twenty one accessions, spanning six botanical families and four orders of magnitude in seed mass, were submitted to a battery of dose-response experiments with eight to ten treatments and four replicates each. The experiments allows to determine the sensitivity of each accession based on the germination inhibition. Essential oil from Baccharis psiadioides (Less.) Joch. Mull. (Asteraceae) was used as phytotoxin. Germination inhibition was calculated with the median effective dose (ED₅₀) with a log-logist regression model, which corresponds to the dosage of essential oil capable of inhibiting the germination from 50% of the sample (thirty seeds) compared to the control of each accession. Results showed a positive correlation between seed size and ED₅₀. Small seeds needed lower quantities of essential oil to inhibit germination whereas larger seeds needed more than twice essential oil doses. This pattern has been reported for aqueous extract with isoflavonoids, phenolic acid derivatives, isothiocyanates, coumarins and now are observed for essential oil derived from terpenoid pathway. Seed size is related with the amount of the nutrient reserve provided for the embryo by the mother plant, thus, small-seeded species generally have fewer reserves with which to support growing embryo and seedling respiration during periods of stress-induced. Furthermore, small-seeded have greater amounts of root length per unit of root mass, providing greater absorptive surface area through which phytotoxins might enter and cause subsequent damages. Effects reported herein may be a pattern for action of other essential oils, however, other studies may be conducted relating other seed attributes as seed reserve or embryo size.

1 - Universidade Federal do Rio Grande do Sul, Departamento de Botânica, Av. Bento Gonçalves, 9500, Instituto de Biociências, Porto Alegre, RS, 91501- 970, Brazil
2 - Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Instituto de Biociências, Porto Alegre, RS, 91501- 970, Brazil

Keywords:
none specified

Presentation Type: Poster
Session: P, Physiology & Ecophysiology
Location: Exhibit Hall/Omni Hotel
Date: Monday, June 26th, 2017
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPE012
Abstract ID:597
Candidate for Awards:None