iCal
Room:
Leipziger KUBUS | Hall 2
Topic:
1.1 Roots and soil structure – mutual feedbacks and their role in maintaining and restoring soil functions
Form of presentation:
Lecture
Duration:
30 Minutes
04:00 pm
Mangrove species found in contrasting environments show differing phytohormonal responses to variation in soil bulk density
Dr. Anne Ola | Canada
Show details
Authors:
Dr. Anne Ola | Canada
Ian C. Dodd
Catherine E. Lovelock
Mangrove species show contrasting root growth responses to variation in soil bulk density (BD). However, very little is known about the regulatory mechanisms that trigger these responses.
Root concentrations of multiple plant hormones were measured in seedlings of two mangrove species (Avicennia marina and Rhizophora stylosa) grown in high and low BD soils. Moreover, possible effects of ethylene were studied by applying the ethylene biosynthesis inhibitors cobalt chloride (CoCl2) and aminoisobutyric acid (AIB).
Increases in BD inhibited root growth in R. stylosa, but not in A. marina. Variation in soil BD had no effect on root hormone levels of R. stylosa, but loose soils increased 1-aminocyclopropane-1-carboxylic acid in A. marina roots whilst decreasing salicylic acid and gibberellin. Further, ethylene inhibitors enhanced root growth of R. stylosa, while AIB inhibited root growth in A. marina. Both ethylene inhibitors increased indole-3-acetic acid and reduced isopentenyl adenine levels in R. stylosa, while CoCl2 increased salicylic acid. The effects of ethylene inhibitors on gibberellin concentrations depended on soil BD. In A. marina, AIB increased trans-zeatin regardless of soil BD and salicylic acid levels in loose soils.
Whilst salicylic acid is central to root growth responses to variation in BD in A. marina, the interaction of ethylene and gibberellin drives responses in R. stylosa. Hormonal interactions involving ethylene potentially reflect the adaptations of the species to differing conditions within the intertidal zone, with A. marina behaving like an aquatic species and R. stylosa behaving like a terrestrial species.