Chloroplast the booting stage, a low temperature cause pollen

Chloroplast biogenesis and its molecular
complexities are still under characterization. The chloroplast itself can be
considered as a separate entity within the plant cell because it contains its
own genome. The genetic system of chloroplast and its coordination with the
nucleocytosolic system, the routing and import of nucleus encoded proteins
together with the organellar division, all contribute to the biogenesis of
chloroplast. They are controlled by the ubiquitin proteasome system which is
part of a network of regulatory mechanisms that intergrade development into
broader programs of cellular development (Jarvis and Lopez-Juez, 2013). The
thylakoids are considered as one of the most important structures within
chloroplast, and are the internal lipid membranes full of protein complexes
which provide a platform for the light reactions occurred during photosynthesis
(Pribil et al. 2014). In monocotyledon plants like rice (Oryza sativa) genetic studies have shown a different regulation of
chloroplast biogenesis at the adaxial and abaxial side between the midrib of
the leaf and the rest of the leaf blade. In a rice chromatin-remodelling factor
4 (chr4) mutant, it was observed an
albino phenotype only at the adaxial side of the leaves, due to a selective
down-regulation of chloroplast development genes in cells of the adaxial side
(Zhao et al. 2012). Cold stress is a major abiotic constraint to plant growth
and development. In rice, two stages of development play a crucial role and are
known to be sensitive to low temperatures; the seedling stage and the booting
stage. At the seedling stage, low temperatures reduce germination and delay
leaf emergence. Common symptoms in this problem are leaf chlorosis and
yellowing (Cruz et al. 2013), suggesting that low temperature arrests
chloroplast development and functioning. During the booting stage, a low
temperature cause pollen sterility and as a consequence is the decrease in
grain yield (Cruz et al. 2013). A low temperature causes swelling of the
thylakoid lamellae, vesiculation of the thylakoid, and ultimately damage of the
entire chloroplast. Low temperatures can affect and inhibit electron transport
and the carbon assimilation apparatus such as the Calvin cycle, ATP synthase,
and RuBisCo (Yamori et al. 2011; Hasanuzzaman et al 2013).