Zinc affects physiology and biosynthesis of medicinal components in
Dendrobium nobile Lindl.
Abstract
The growth of Dendrobium nobile is often stressed by zinc. To study the
effect of zinc on the growth and biosynthesis of medicinal components,
external zinc was regularly sprayed on Dendrobium nobile. The results
showed that the net photosynthetic rate, transpiration rate, stomatal
conductance, chlorophyll A and B of leaves increased first and then
decreased with the increase of zinc concentration. At 400 μmol/L, they
reached the maximum value, indicating that a certain dose of zinc could
promote the photosynthesis of Dendrobium nobile. When the concentration
of zinc was 400 μmol/L, which could promote the synthesis of SOD, the
content of APX and AsA reach the maximum. The content of polysaccharide
reached the maximum on the 7th day, the content of polyphenols reached
the maximum on the 14th day. This result suggests that exogenous zinc
can promote the accumulation of active components in Dendrobium nobile,
and when the zinc concentration is 400 μmol/L, the promoting effect is
greatest. While, it was found that the polysaccharide can combine with
zinc well to form polysaccharide-zinc chelate, and transform inorganic
zinc into organic zinc, which was stored in the form of
polysaccharide-Zn in vivo and reduced the damage to Dendrobium nobile by
Zn-stress