100
Keywords Ethylene • Jasmonates • Red algae • Sporogenesis • Seaweed reproduction • Volatiles
Contents
5.1 Introduction ...................................................................................................................... 100
5.2 Volatile Compounds Are All Around: How Do Algae Smell? ......................................... 101
5.3 Complexity of Factors Drives Volatile Emission by Algae .............................................. 102
5.4 Profiling the Physiological Responses of Algae to Volatiles ........................................... 104
5.5 Ethylene and Methyl Jasmonate as Priming Volatile Growth Regulators
that Affect Reproduction in Seaweeds ............................................................................. 106
5.6 Genetic ‘Dissection’ of Volatile Emission in the Reproduction of Macroalgae .............. 109
5.7 Conclusions ...................................................................................................................... 111
References ................................................................................................................................. 112
5.1 Introduction
Plants produce and emit large amounts of volatile organic compounds. The influence of scent is deemed to play several roles at the physiological and ecological
level as defence compounds, as stabilisers and as protection for the plasma membrane against higher temperature and alterations of nearby flowering plants (Qualley
and Dudareva 2010). One of the main roles of airborne compounds is also their
involvement as signals to other organisms, and in this, volatiles facilitate interactions with the environment.
Volatile organic compounds in marine algae can also act as chemical communicators, where algae sense gaseous signals. Moreover, algae emit volatiles that vary
both quantitatively and qualitatively depending on time and space. In recent years,
a broad range of these volatiles have been identified in a physiological complex pattern, inferring that algae must also somehow integrate signals not only to reply to
environmental status but also as a response to their growth and development capacity. Evidence comes from macroalga mats, which suffer sudden increments in the
number of reproductive structures and correspondingly abrupt decreases in biomass
(Garcia-Jimenez personal communication). To date, of the most important proceeding in algae, reproduction events are not still well understood and remain disputed.
Reproduction is usually stimulated by environmental factors such as light, temperature and availability of nutrients that influence the transition from the vegetative
phase to the reproductive phase (Cole and Sheath 1990). Furthermore, as described
below, volatile production has also seen to be affected by (a)biotic factors. Thus, the
effects of several interacting environmental factors, and the fact that one of these
factors can also vary in one of the multiple aspects, such as light with its intensity,
quality, the length of the day and the number of photons, make it difficult to offer a
comprehensive interpretation of the role of volatiles in reproductive processes.
Moreover, responses to volatile growth regulators are reported to show great
inconsistency in algae. Assuming uniform volatile sampling, the key to understanding this reasoning is the cellular competence of algae with respect to plant horP. Garcia-Jimenez and R.R. Robaina
Keywords Ethylene • Jasmonates • Red algae • Sporogenesis • Seaweed reproduction • Volatiles
Contents
5.1 Introduction ...................................................................................................................... 100
5.2 Volatile Compounds Are All Around: How Do Algae Smell? ......................................... 101
5.3 Complexity of Factors Drives Volatile Emission by Algae .............................................. 102
5.4 Profiling the Physiological Responses of Algae to Volatiles ........................................... 104
5.5 Ethylene and Methyl Jasmonate as Priming Volatile Growth Regulators
that Affect Reproduction in Seaweeds ............................................................................. 106
5.6 Genetic ‘Dissection’ of Volatile Emission in the Reproduction of Macroalgae .............. 109
5.7 Conclusions ...................................................................................................................... 111
References ................................................................................................................................. 112
5.1 Introduction
Plants produce and emit large amounts of volatile organic compounds. The influence of scent is deemed to play several roles at the physiological and ecological
level as defence compounds, as stabilisers and as protection for the plasma membrane against higher temperature and alterations of nearby flowering plants (Qualley
and Dudareva 2010). One of the main roles of airborne compounds is also their
involvement as signals to other organisms, and in this, volatiles facilitate interactions with the environment.
Volatile organic compounds in marine algae can also act as chemical communicators, where algae sense gaseous signals. Moreover, algae emit volatiles that vary
both quantitatively and qualitatively depending on time and space. In recent years,
a broad range of these volatiles have been identified in a physiological complex pattern, inferring that algae must also somehow integrate signals not only to reply to
environmental status but also as a response to their growth and development capacity. Evidence comes from macroalga mats, which suffer sudden increments in the
number of reproductive structures and correspondingly abrupt decreases in biomass
(Garcia-Jimenez personal communication). To date, of the most important proceeding in algae, reproduction events are not still well understood and remain disputed.
Reproduction is usually stimulated by environmental factors such as light, temperature and availability of nutrients that influence the transition from the vegetative
phase to the reproductive phase (Cole and Sheath 1990). Furthermore, as described
below, volatile production has also seen to be affected by (a)biotic factors. Thus, the
effects of several interacting environmental factors, and the fact that one of these
factors can also vary in one of the multiple aspects, such as light with its intensity,
quality, the length of the day and the number of photons, make it difficult to offer a
comprehensive interpretation of the role of volatiles in reproductive processes.
Moreover, responses to volatile growth regulators are reported to show great
inconsistency in algae. Assuming uniform volatile sampling, the key to understanding this reasoning is the cellular competence of algae with respect to plant horP. Garcia-Jimenez and R.R. Robaina