Biomedical Engineering Reference
In-Depth Information
maize [ 62 ]. However, M.
giganteus cannot survive winter conditions at some
North European areas, particularly in the first season when started from tissue-
cultured plantlets [ 17 ]. Clifton-Brown and Lewandowski [ 105 ] compared cold
tolerance in Miscanthus spp. using a test for freezing tolerance, finding out that
the lethal temperature at which 50 % of rhizomes killed (LT 50 ) for M.
giganteus
and M. sacchariflorus genotypes was
3.4 C, while LT 50 for M. sinensis genotype
6.3 C. Low temperatures during spring delay the timing for shoot
emergence, subsequently reduce growth time, and reduce Miscanthus yields in
autumn [ 90 ]. The onset of frost after shoot emergence kills shoots and reduces
shoot number. Some genotypes of M. sinensis are able to grow shoots at lower
temperatures than M.
Sin-H6 was
giganteus [ 90 ].
Characterization of the lignin, cellulose, and mineral content is useful for
breeding programs for biorefinery feedstock development. For biorefineries,
processing Miscanthus with low lignin content is preferred because high lignin
content decreases the efficiency of scarification process and increases the cost of
pretreatment of feedstock [ 81 ]. On the other hand, high lignin concentration gives
higher heating value that is preferable for combustion [ 106 ]. M. sacchariflorus and
M.
giganteus constantly showed higher lignin content and lower hemicellulose
content than M. sinensis , and variation of lignin content was observed among
different genotypes [ 81 ]. Our evaluation of lignin content also showed substantial
variation among genetic resources from different collection sites (unpublished).
For biomass combustion process, good quality depends largely on minimizing
moisture, ash, potassium (K), chloride, nitrogen (N), and sulfur (S). Delaying the
harvest of Miscanthus spp. improved the combustion quality by reducing ash,
chloride, nitrogen, and moisture [ 60 ]. Silicon (Si) is important for grass species to
increase the plant resistance to lodging and drought; improve disease, insect, and
nematode resistance; improve soil nutrient availability; and improve reproductive
fertility [ 107 ]. However, silicon reacts with aluminum, chlorine, potassium, and
other alkalis to form slag during the combustion process. Woli et al. [ 107 ] found
that Si concentration in M.
giganteus plants from several locations in the USA
ranged from 0.72 to 1.62 %, indicating that soil type influences Si uptake. Si
concentration in M. sinensis ranged between 0.81 and 3.56 %.
Interspecific Hybridization
The currently propagated natural triploid hybrid M.
giganteus clone came from a
plant that was introduced to Denmark in 1935 from Yokohama, Japan, by a Danish
plant collector, Aksel Olsen [ 108 ].
Being the center of origin of Miscanthus species, there are many sympatric
populations of different Miscanthus species in Japan. In those overlapping
populations, natural hybrids between Miscanthus species can be found [ 36 , 38 ,
109 ]. Recently, three triploid hybrids were found in seeds collected from
M. sacchariflorus that grew in Kushima, southern Japan [ 32 ]. The plants were
confirmed to have 57 chromosomes. Through internal transcribed spacer (ITS)
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