Style head in Apocynaceae: a very complex secretory activity performed by one tissue
Nuptial glands are very diverse and associated with different pollination mechanisms. The greater the specificity in the pollen transfer mechanism from anther to stigma, the greater the morphological elaboration of flowers and functional complexity of the nuptial glands. In Apocynaceae, pollination...
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Format: | Article |
Language: | English |
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PAGEPress Publications
2024-04-01
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Series: | European Journal of Histochemistry |
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Online Access: | https://www.ejh.it/ejh/article/view/4027 |
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author | Danielle Maximo Diego Demarco |
author_facet | Danielle Maximo Diego Demarco |
author_sort | Danielle Maximo |
collection | DOAJ |
description |
Nuptial glands are very diverse and associated with different pollination mechanisms. The greater the specificity in the pollen transfer mechanism from anther to stigma, the greater the morphological elaboration of flowers and functional complexity of the nuptial glands. In Apocynaceae, pollination mechanisms reached an extreme specificity, a fact that was only possible due to an extreme morphological synorganization and a profusion of floral glands. Although these glands are of different types, the vast majority have secretory cells only in the epidermis. In general, these epidermal cells produce many different compounds at the same time, and previous studies have demonstrated that in the style head, the functional complexity of epidermis has become even greater. Four types of style head are found in the family, which have different degrees of functional complexity in relation to the secretion produced and pollen dispersal mechanism. The secretion is fluid in types I, II and III, and the pollen is dispersed and adhered to the pollinator by the secretion produced by the style head. In type IV, the secretion hardens and acquires a specific shape, moulded by the spatial constraints of the adjacent floral organs. This evolutionary alteration is accompanied by changes in the structure and arrangement of the secretory cells, as well as in pollen aggregation and position of stigma. Histochemical analysis has shown that the secretion is mixed and highly complex, especially in the style head type IV, where the secretion, called translator, is formed by a rigid central portion, which adheres to the pollinator, and two caudicles that attach to two pollinia. The translator has a distinct composition in its different parts. Further studies are needed to answer the new questions that have arisen from the discovery of this highly functional complexity of the secretory tissue.
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format | Article |
id | doaj.art-6b0c22aa34894f5c9e98bc326cef13c1 |
institution | Directory Open Access Journal |
issn | 1121-760X 2038-8306 |
language | English |
last_indexed | 2024-04-24T15:21:19Z |
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publisher | PAGEPress Publications |
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series | European Journal of Histochemistry |
spelling | doaj.art-6b0c22aa34894f5c9e98bc326cef13c12024-04-02T08:00:38ZengPAGEPress PublicationsEuropean Journal of Histochemistry1121-760X2038-83062024-04-0168110.4081/ejh.2024.4027Style head in Apocynaceae: a very complex secretory activity performed by one tissueDanielle Maximo0Diego Demarco1Departamento de Botânica, Instituto de Biociências, Universidade de São PauloDepartamento de Botânica, Instituto de Biociências, Universidade de São Paulo Nuptial glands are very diverse and associated with different pollination mechanisms. The greater the specificity in the pollen transfer mechanism from anther to stigma, the greater the morphological elaboration of flowers and functional complexity of the nuptial glands. In Apocynaceae, pollination mechanisms reached an extreme specificity, a fact that was only possible due to an extreme morphological synorganization and a profusion of floral glands. Although these glands are of different types, the vast majority have secretory cells only in the epidermis. In general, these epidermal cells produce many different compounds at the same time, and previous studies have demonstrated that in the style head, the functional complexity of epidermis has become even greater. Four types of style head are found in the family, which have different degrees of functional complexity in relation to the secretion produced and pollen dispersal mechanism. The secretion is fluid in types I, II and III, and the pollen is dispersed and adhered to the pollinator by the secretion produced by the style head. In type IV, the secretion hardens and acquires a specific shape, moulded by the spatial constraints of the adjacent floral organs. This evolutionary alteration is accompanied by changes in the structure and arrangement of the secretory cells, as well as in pollen aggregation and position of stigma. Histochemical analysis has shown that the secretion is mixed and highly complex, especially in the style head type IV, where the secretion, called translator, is formed by a rigid central portion, which adheres to the pollinator, and two caudicles that attach to two pollinia. The translator has a distinct composition in its different parts. Further studies are needed to answer the new questions that have arisen from the discovery of this highly functional complexity of the secretory tissue. https://www.ejh.it/ejh/article/view/4027glandshistochemistrypollinariumsecretionsynorganizationtranslator |
spellingShingle | Danielle Maximo Diego Demarco Style head in Apocynaceae: a very complex secretory activity performed by one tissue European Journal of Histochemistry glands histochemistry pollinarium secretion synorganization translator |
title | Style head in Apocynaceae: a very complex secretory activity performed by one tissue |
title_full | Style head in Apocynaceae: a very complex secretory activity performed by one tissue |
title_fullStr | Style head in Apocynaceae: a very complex secretory activity performed by one tissue |
title_full_unstemmed | Style head in Apocynaceae: a very complex secretory activity performed by one tissue |
title_short | Style head in Apocynaceae: a very complex secretory activity performed by one tissue |
title_sort | style head in apocynaceae a very complex secretory activity performed by one tissue |
topic | glands histochemistry pollinarium secretion synorganization translator |
url | https://www.ejh.it/ejh/article/view/4027 |
work_keys_str_mv | AT daniellemaximo styleheadinapocynaceaeaverycomplexsecretoryactivityperformedbyonetissue AT diegodemarco styleheadinapocynaceaeaverycomplexsecretoryactivityperformedbyonetissue |