8 Biofilter Aquaponic System for Nutrients …
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8.6.2 Photoperiod Effect on Plant Growth
Photoperiodism is one of the most significant and complex aspects of the interaction
between plants and their environment. It is defined as plant responses to day length,
enabling living organisms to adapt to seasonal changes. In Heliconia psittacorum
case, it has been reported that the main factors influencing flowering are irradiance
and temperature. However, photoperiod also appears to have a slight influence (Xu
et al. 2016). The most widely used photoperiods are 12 h of light/12 h of darkness
or 16 h light/8 h of darkness (De Silva et al. 2012).
In most of the studies carried out using different species of Heliconia, the photoperiod used was 16 h. In Heliconia stricta, a seasonal pattern of flowering has been
recorded, yields are greater for plants grown at 8 h photoperiods than under natural
day length. No flowering occurred in long days. For Heliconia aurantiaca, it has been
observed that under glasshouse conditions in Denmark, flowering only occurs during
November to February. This pattern suggests that flowering might be influenced by
photoperiod. Since Heliconia latispatha is an attractive plant that shows potential as
a cut flower, particularly if flowering could be extended to a greater part of the year.
8.6.3 Concept of Phytoremediation Technology
Phytoremediation is known as a naturally occurring process and being documented
by humans for more than 300 years ago (Bindu 2004). Since then, some plants’
capabilities to survive in polluted areas and to ease pollutants removal from the
environment had been discovered by humans. The number of plants depends on
the size of the space available and the desired plant density. However, greater plant
densities will achieve canopy closure more rapidly, therefore, water uptake will
also reach a maximum rate more quickly. Lu et al. (2008) stated that there are three
principles for operating an aquatic phytoremediation system. Firstly, implementation
and identification of efficient aquatic plant systems. Secondly, uptake of dissolved
nutrients including N, P and metals by growing plants. Lastly, harvest and beneficial
use of the plant biomass produced from the remediation system. In order to ensure
optimum plant density, the regular harvest grown-up biomass from water bodies is
necessary. Otherwise, the dead plant tissues will decompose and then release the
stored nutrients back to the environment.
There are five types of phytoremediation mechanisms for pollutant removal,
namely, phytovolatilization, phytodegradation, phytoextraction, rhizofiltration and
phytostabilization. Phytovolatilization is the extraction, and subsequent compounds
are released in gaseous form from the foliage into atmosphere. Phytodegradation is
the conversion of organic pollutants into non-toxic forms by plants and associated
microorganisms which occurs at rhizosphere or plant internals. Meanwhile, phytoextraction is the natural ability of plant to take up substances (e.g. organic compounds) from the environment and followed by sequestration of those substances
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8.6.2 Photoperiod Effect on Plant Growth
Photoperiodism is one of the most significant and complex aspects of the interaction
between plants and their environment. It is defined as plant responses to day length,
enabling living organisms to adapt to seasonal changes. In Heliconia psittacorum
case, it has been reported that the main factors influencing flowering are irradiance
and temperature. However, photoperiod also appears to have a slight influence (Xu
et al. 2016). The most widely used photoperiods are 12 h of light/12 h of darkness
or 16 h light/8 h of darkness (De Silva et al. 2012).
In most of the studies carried out using different species of Heliconia, the photoperiod used was 16 h. In Heliconia stricta, a seasonal pattern of flowering has been
recorded, yields are greater for plants grown at 8 h photoperiods than under natural
day length. No flowering occurred in long days. For Heliconia aurantiaca, it has been
observed that under glasshouse conditions in Denmark, flowering only occurs during
November to February. This pattern suggests that flowering might be influenced by
photoperiod. Since Heliconia latispatha is an attractive plant that shows potential as
a cut flower, particularly if flowering could be extended to a greater part of the year.
8.6.3 Concept of Phytoremediation Technology
Phytoremediation is known as a naturally occurring process and being documented
by humans for more than 300 years ago (Bindu 2004). Since then, some plants’
capabilities to survive in polluted areas and to ease pollutants removal from the
environment had been discovered by humans. The number of plants depends on
the size of the space available and the desired plant density. However, greater plant
densities will achieve canopy closure more rapidly, therefore, water uptake will
also reach a maximum rate more quickly. Lu et al. (2008) stated that there are three
principles for operating an aquatic phytoremediation system. Firstly, implementation
and identification of efficient aquatic plant systems. Secondly, uptake of dissolved
nutrients including N, P and metals by growing plants. Lastly, harvest and beneficial
use of the plant biomass produced from the remediation system. In order to ensure
optimum plant density, the regular harvest grown-up biomass from water bodies is
necessary. Otherwise, the dead plant tissues will decompose and then release the
stored nutrients back to the environment.
There are five types of phytoremediation mechanisms for pollutant removal,
namely, phytovolatilization, phytodegradation, phytoextraction, rhizofiltration and
phytostabilization. Phytovolatilization is the extraction, and subsequent compounds
are released in gaseous form from the foliage into atmosphere. Phytodegradation is
the conversion of organic pollutants into non-toxic forms by plants and associated
microorganisms which occurs at rhizosphere or plant internals. Meanwhile, phytoextraction is the natural ability of plant to take up substances (e.g. organic compounds) from the environment and followed by sequestration of those substances