Biology Reference
In-Depth Information
14.2 Greening Group Affiliation of Green Plants:
Discovery of the Divinyl (DV) and Monovinyl
(MV) Greening Groups of Plants
Prior to 1985 it was assumed that the greening process was uniform across all green
plants i.e. all green plants formed Chl via the same Chl biosynthetic route(s).
Several observations made in the early 1980s, helped dispel, this misconception
as described below.
The first observation related to multiple greening groups of plants was made
in 1985. By then the Chl biosynthetic heterogeneity was already established
(Rebeiz et al. 1983 ). It was realized that different species of plants greened
differently by using different Chl Biosynthetic routes. Thus, On the basis of the
DV-MV biosynthetic heterogeneity, green plants were initially classified into three
different greening groups depending upon MV or DV Pchlide a accumulation
during the dark and light phases of the photoperiod (Carey and Rebeiz 1985 ;
Ioannides et al. 1994 ; Shioi and Takamiya 1992 ). Dark Divinyl-Light Divinyl
(DDV-LDV) plants, such as Pogostemon cablin , cucumber ( Cucumis sativus ),
velvetleaf ( Abutilon theophrastii ), common morningglory ( Ipomea purpurea ),
prickly sida ( Sida spinosa ), and mustard ( Brassica nigra ), accumulated mainly
DV Pchlide a at night and in daytime the analyzed Pchlide a pool consisted mainly
of DV Pchlide a . All representative primitive plant species, including algae,
bryophytes, ferns, and gymnosperms, fell into this greening group. This led
Ioannides et al . ( 1994 ) to propose that this greening group is evolutionary ancestral
(Table 14.1 ).
Dark Monovinyl-Light Monovinyl (DMV-LMV) plants, such as barnyardgrass
( Echinochloa crus-galli ) and johnsongrass ( Sorghum halepense ), accumulated
mainly MV Pchlide a at night and in daytime the Pchlide a consisted mainly of
MV Pchlide a (Table 14.1 ). This greening group comprised a small number of
plants, and evolutionary studies suggested that it is derived (Ioannides et al. 1994 ).
Finally, it was observed that Dark Monovinyl-Light Divinyl (DMV-LDV) plants
such as French bean ( Phaseolus vulgaris L. ), corn ( Zea mays ), wheat ( Triticum
aestivum ), wild oat ( Avena fatua ), barley ( Hordeum vulgare ), soybean ( Glycine
max ), lambsquarter ( Chenopodium album ), jimsonweed ( Datura strmonium ), red-
root pigweed ( Amaranthus retroflexus ), cocklebur ( Xanthium stumarium ), etc.,
accumulated MV Pchlide a at night. In daytime the Pchlide a pool consisted mainly
of DV Pchlide a . This greening group comprised by far the largest number of
surveyed plant species, and evolutionary studies suggested that it was evolutionary
intermediate (Ioannides et al. 1994 ). Plant species of major agronomic importance
belonged to this group.
Table 14.1 extracted from Ioannides et al. ( 1994 ), depicts a brief survey of
various plant species belonging to the three greening groups mentioned above.
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