Open AccessDetecting Activity of Juvenile Phase-Specific Translocatable Substances that Influence Rooting Potential Using In Vitro Rooting Assays and Expression of a Specific Gene
Author(s) -
Wesley P. Hackett,
M. Raviv,
Anath Bandhu Das,
O. Reuveni,
Arie L. Gutman
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.32747/1998.7613038.bard
Subject(s) - hedera helix , biology , lamina , petiole (insect anatomy) , auxin , botany , cutting , juvenile , gene expression , gene , clone (java method) , microbiology and biotechnology , genetics , hymenoptera
The objectives of the project for which substantial effort was put forth were to: 1) Verify the relationship between expression of a cDNA clone (HW103) and the rooting potential of reciprocally grafted cuttings of juvenile and mature lamina and petioles of Hedera helix L. 2) Detect rooting promoter fractions in exudates from the juvenile leaves of H. Helix by assaying for rooting with leaf petioles of juvenile and mature plants. 3) Isolate, purify and identify compounds which show activity in assays for rooting potential. Some objectives or aspects of the objectives of the original proposal were not pursued for the reasons put forth in the body of the report. The most significant findings of the project are: 1) The MS medium is a better medium than Romberg medium for performing the leaf petiole rooting assay. 2) HW103 gene expression is cell-type specific with higher levels of expression in mature than juvenile phase H. Helix petioles as evidenced by in situ hybridization which suggests a negative relationship between HW103 expression in specific cells involved in root initiation and the lack of rooting potential in mature petioles 3) HW103 gene expression may be lower in mature petioles which had been grafter to a juvenile H. Helix lamina than mature petioles that had been grafted to a mature lamina and this putative lower expression is related to formation of a higher number of roots. 4) HW103 gene expression is not related to auxin induced ethylene production. 5) Two distinct compounds that possess root initiation promoting activity can be detected mainly in diffusate of juvenile H. Helix leaves using mung bean hypocotyls and H. Helix leaf petioles in vitro. 6) H. Helix diffusate active fractions do not insistenlty promote rooting in avocado mini-cuttings. 7) Chemical identification of the active rooting compounds was not accomplished because of the death of Prof. Becker, one of the collaborators, and the resultant loss of his data. These results indicate that these may be a molecular basis for reduced rooting potential in mature H. Helix petioles and that there are diffusible (translocatable) compounds in juvenile H. Helix leaves which promote rooting in juvenile and mature H. Helix petioles and mung bean hypocotyls.