||Not greater than 1 cm, the smallest sizes in Wolffia, from 2-5
Morphological structure - vegetative body - listets or fronds.
||The form of fronds can be reniform, rounded, eliptical, lancate, linear,
||Plants are long-lived and overwinter rarely as seeds, more
commonly they overwinter in the form of fronds. Sometimes the fronds
become thickened, more rounded and fill up with starch. Such formations
call turions or "quiescent kidneys." They are encountered in Spirodela.
In autumn turions submerge to the bottom of the reservoir, and then in
the spring they float up and begin to multiply further. (Pashkovich E,
Yudin B.S., 1978)
Duckweed and the Snail
trisulca. It is interesting that this small-sized plant - widespread
to abundant - is never attacked by snails. This is because of prickly
crystals of calcium oxalate, which are contained in its cells. Fearing
these crystals, snails do not touch it.(Zolotnitskiy N.F., 1993).
V.I. Vernadskiy and duckweeds
On the chemical elementary composition of duckweeds (Lemna) as a
In this work, Vernadskiy studies four duckweeds: Lemna minor,
polyrrhiza, Lemna gibba, Lemna trisulca. It was established
that in the species, which grow in different geographical zones, can vary
in their chemical composition. For the experiment the
duckweeds, which grow in Kiev region and Peterhof region, were studied.
Fourteen elements were investigated:
Н2О, C, N, H, O, K, Na, Ca, Mg, Mn, Fe, Cl, P, S,
It was established that the chemical composition for the separate species
of duckweeds differed little depending on the locality or terrain.
Identifiable differences in chemical composition are specific to the different
species of duckweeds.
On the position of chloroplasts in ivy-leaf duckweed
||Ivy-leaf duckweed can change the color of its fronds.
In indirect or scattered light chloroplasts are arranged along the walls
of the cells, on surface of which the light/world falls at a right angle,
i.e., in the cylindrical parenchyma cells of the leaf on the parallel surfacesto
the leaf surface, and therefore, the tissue of such cells seems dark green,
if we look on them from the side, whence light/world falls.
As soon as direct sunlight begins to have its effect, chloroplasts are
transferred to the walls of cells, in parallel to the direction of the
incident rays/beams. If these are parenchyma cells, then chloroplasts
are grouped on long side walls, while short and lying/horizontal the right
angle to incident light walls prove to be those deprived of chlorophyll
and without pigmentation.
One can see well this displacement especially well in ivy-leaf duckweed,
whose simple tissues contain only two layers of short green cells.