The effect of soil drought on the phloem fiber development in long-fiber flax

The effects of soil drought on various stages of phloem fiber development during the period of flax (Linum usitatissimum L.) rapid growth were assessed. The formation of the secondary cell wall was shown to be most retarded. The content of a tissue-specific galactan was reduced especially sharply, and its side chains were changed. Under conditions of pronounced stress-induced plant growth retardation, fiber intrusive growth was suppressed relatively softly: their number on the stem transverse sections was reduced only by 16%. However, this determined irreversible diversity in the fiber length in various stem regions. Such insignificant suppression of intrusive growth under osmotic stress (simultaneously with substantial retardation of plant growth and metabolism inhibition) indicates the functioning of special mechanisms of its regulation.