CHAPTER ONE
INTRODUCTION
The depletion of world petroleum reserves, oil price hikes and the increased
environmental concerns have stimulated the search for alternative sources to
petroleum based fuel, including diesel fuel. Biodiesel extracted from vegetable oil
is one such renewable alternative under consideration. The production of biodiesel
would be cheap as it could be extracted from non-edible oil sources (Openshaw,
2000; Francis et al., 2005; Chhetri et al., 2008; Dermibas, 2009).
Jatropha curcas L. (physic nut), a non-edible oil bearing and drought hardy
shrub with ecological and other advantages belonging to the family Euphorbiacea,
was found to be a potential renewable source of biodiesel (Raju and Ezradanam,
2002; Chhetri et al., 2008; Idu et al., 2009). In recent years, the plant has received
extensive attention due to its medicinal importance and for its seed oil as a
potential commercial source of biodiesel. The oil can be used as a mixed fuel for
diesel/gasoline engines after transesterification (Achten et al., 2007; Abdullah et
al., 2011; Ram et al., 2012). The seed or oil is not edible due to the presence of a
toxic substance known as curcin (Joubert et al., 1984 and Makkar et al., 1998). The
oil is conventionally used in making soaps, dyes, candles, paints, lubricants and
medicinally as a purgative (Kumar and Sharma, 2000; Misra and Misra, 2010).
Conventionally, the seeds and cuttings are used for its propagation but the
constraints to seed germination caused by dormancy induced by hard seed coat,
poorly developed endosperm and abortion of hybrid embryos in seeds and the
seasonal limitation of cuttings are the major constraints. It has also been reported
that vegetative cuttings are not deep rooted and are easily uprooted as they do not
form a tap root system (Sujatha and Mukta, 1996; Openshaw, 2000; Idu et al.,
2009). To overcome the above mentioned difficulties in conventional methods, in
vitro cultivation of the plant is the better option as it offers rapid and continuous
supply of better planting materials (Sardana et al., 1998; Sathya, 2007; Ram et al.,
2012). The evaluation of micropropagated J. curcas has revealed that they were at
par with seed propagated plants in terms of yield and yield related traits (Sujatha
and Mukta, 1996; Ahmed et al., 2012).
Plant tissue culture and micropropagation techniques play a great role in
genetic conservation programs and management of botanical collection of plants in
a very efficient manner (Smith, 2000; Kyesmu et al., 2004; Sathya, 2007). Embryo
culture techniques can eliminate the constraints to seed germination caused by seed
coat and endosperm and provide a long term storage of germplasm in a disease and
insect free form (Okezie et al., 1994).
In vitro grown plants are devoid or insufficient of photosynthesis, due to
growth taking place in condition unsuitable for photosynthesis. So, they need a
readily available source of carbon which is usually provided in the culture medium
at 3 % (Garcia et al., 2002; Sadhu, 2007; Okafor et al., 2012; Ram et al., 2012;
Rafique et al., 2013). Murashige and Skoog medium (MS) is the most commonly
and widely used culture medium in most plant tissue
INTRODUCTION
The depletion of world petroleum reserves, oil price hikes and the increased
environmental concerns have stimulated the search for alternative sources to
petroleum based fuel, including diesel fuel. Biodiesel extracted from vegetable oil
is one such renewable alternative under consideration. The production of biodiesel
would be cheap as it could be extracted from non-edible oil sources (Openshaw,
2000; Francis et al., 2005; Chhetri et al., 2008; Dermibas, 2009).
Jatropha curcas L. (physic nut), a non-edible oil bearing and drought hardy
shrub with ecological and other advantages belonging to the family Euphorbiacea,
was found to be a potential renewable source of biodiesel (Raju and Ezradanam,
2002; Chhetri et al., 2008; Idu et al., 2009). In recent years, the plant has received
extensive attention due to its medicinal importance and for its seed oil as a
potential commercial source of biodiesel. The oil can be used as a mixed fuel for
diesel/gasoline engines after transesterification (Achten et al., 2007; Abdullah et
al., 2011; Ram et al., 2012). The seed or oil is not edible due to the presence of a
toxic substance known as curcin (Joubert et al., 1984 and Makkar et al., 1998). The
oil is conventionally used in making soaps, dyes, candles, paints, lubricants and
medicinally as a purgative (Kumar and Sharma, 2000; Misra and Misra, 2010).
Conventionally, the seeds and cuttings are used for its propagation but the
constraints to seed germination caused by dormancy induced by hard seed coat,
poorly developed endosperm and abortion of hybrid embryos in seeds and the
seasonal limitation of cuttings are the major constraints. It has also been reported
that vegetative cuttings are not deep rooted and are easily uprooted as they do not
form a tap root system (Sujatha and Mukta, 1996; Openshaw, 2000; Idu et al.,
2009). To overcome the above mentioned difficulties in conventional methods, in
vitro cultivation of the plant is the better option as it offers rapid and continuous
supply of better planting materials (Sardana et al., 1998; Sathya, 2007; Ram et al.,
2012). The evaluation of micropropagated J. curcas has revealed that they were at
par with seed propagated plants in terms of yield and yield related traits (Sujatha
and Mukta, 1996; Ahmed et al., 2012).
Plant tissue culture and micropropagation techniques play a great role in
genetic conservation programs and management of botanical collection of plants in
a very efficient manner (Smith, 2000; Kyesmu et al., 2004; Sathya, 2007). Embryo
culture techniques can eliminate the constraints to seed germination caused by seed
coat and endosperm and provide a long term storage of germplasm in a disease and
insect free form (Okezie et al., 1994).
In vitro grown plants are devoid or insufficient of photosynthesis, due to
growth taking place in condition unsuitable for photosynthesis. So, they need a
readily available source of carbon which is usually provided in the culture medium
at 3 % (Garcia et al., 2002; Sadhu, 2007; Okafor et al., 2012; Ram et al., 2012;
Rafique et al., 2013). Murashige and Skoog medium (MS) is the most commonly
and widely used culture medium in most plant tissue
