Impact of the application of a cambium marking methodology in the evaluation of vessels formed exclusively in the xylem under treatment of water stress

Abstract

Xylem formation is a cyclical process developed from cambium. The seasonal activity of cambium can be studied with different methodologies (in this work a mechanical injury method). Accurately identifying the xylem formed during a period of abiotic stress treatment would allow correct interpretations of the specific effect of stress on xylem production. The objectives were: 1- To assess whether the measurements of the vessels made only in the xylem formed during the period of water stress are more sensitive than when they are made throughout the xylem; 2- Explain the most important points of the marking technique and the subsequent methodological steps in the morphometric analysis. Ten cuttings of Salix matsudana ´NZ692´ were planted in pots: 5 plants were flooded for 35 days and the other 5 plants were control (non-flooded). They subsequently grew for 28 days of recovery. The plants were marked with a scalpel incision at the level of the cambium at the beginning and at the end of the treatment. The vessel’s morphometric analysis was done at three measurement areas: 1- only the treatment area, 2- only the recovery area and 3- all growth (sum of pre-treatment, treatment and post-treatment areas). The vessels produced exclusively during the stress period differed from those formed later and from those measured throughout the stem. Likewise, the cambium marking technique allowed identifying the specific area of ​​xylem formation under water stress. The use of this relatively simple technique can substantially improve the interpretation of anatomical changes that occurred in the xylem under stress.