Abstract Detail

Anatomy and Morphology

Cocoletzi-Vázquez, Eliezer [1], Angeles, Guillermo [2], Gregorio, Glenn [3], Araceli, Patrón [4], Juan Francisco, Ornelas [5].

Bidirectional anatomical effects between the mistletoe Psittacanthus schiedeanus and its evergreen and deciduous hosts.

Parasitism among plants involves a series of modifications in metabolism and morphology. Parasitic plants may tap from its hosts xylem amino acids, organic acids, ions, and water; while from the host’s phloem, they may obtain sugars, ions and amino acids. The hemiparasites are photosynthetic and obtain their resources from the host xylem. The anthropocentric connotation of parasitic plants is that they have negative impacts in hosts of economic importance. By the above the aim of this research was determine the effects caused by Psittacanthus schiedeanus on the morphology and structure of phloem of Liquidambar styraciflua and Quercus germana, two native species of the cloud forest in Mexico. The anatomical interpretations of structure and morphology of phloem in several sections of parasite-host pairwise was made on haustorium and stem samples, which were analyzed quantitatively with optical microscopy and transmission electron microscopy. The secondary phloem of P. schiedeanus was composed of sieve element-companion cell complexes, radial and axial parenchyma fibers and sclereids. In addition, L. styraciflua presented clusters of sclereids in the phloem, while Q. germana had sclereids arranged in tangential bands sometimes disposed parallel to the cambium. The longitudinal axis of the P. schiedeanus forms a right angle with respect to L. styraciflua and Q. germana causing a re-arrangement of phloem and xylem in haustorial zone. In the contact zone, the bark is reduced until be interrupted by transfer cells of the parasite. The sieve elements-companion cells complexes in the parasite are located at one cm from the haustorium forming together with the xylem structures similar to vascular bundles. The interface between the parasite and its host is composed of transfer cells which were characterized by the presence of abundant primary pit fields that may allow the symplasmic continuum among both species. Bidirectional effects are variations in phloem structure of the parasite caused by the host species, as well as changes in phloem structure of the hosts caused by the parasite.

1 - Instituto De Ecologia, A.C., Posgrado, Carretera Antigua A Coatepec 351, El Haya, Xalapa, Veracruz, 91070, Mexico
2 - Instituto de Ecología A. C., Ecología Funcion, Carretera Antigua A Coatepec 351, El Haya, Xalapa, VERACRUZ, 91070, Mexico
3 - Universidade de São Paulo, Dept. de Botânica, Instituto de Biociências, Sao Paulo, Sao Paulo, SP, 05508-900
4 - Instituto Potosino de Investigación Científica y Tecnológica, División de Biología Molecular, San Luis Potosí, San Luis Potosí, SLP, 78216, Mexico
5 - Instituto de Ecología, AC,, Red de Biología Evolutiva, Carretera Antigua A Coatepec 351, El Haya, Xalapa, Veracruz, 91070, Mexico

Keywords:
parasitic plant
Phloem
plasmodesmata
haustorium.

Presentation Type: Oral Paper
Session: 20, Anatomy and Morphology
Location: Fort Worth Ballroom 7/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 8:15 AM
Number: 20002
Abstract ID:544
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award