5 Resin Glands Related to Pollination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
5.1 Resins Produced by Flowers and Inflorescences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
5.2 Resin Glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 736
5.3 Floral Resin: Characteristics and Histochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 738
5.4 The Evolution of Floral Resin Glands Related to Pollination . . . . . . . . . . . . . . . . . . . . . . . 739
6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 739
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740
Abstract
Floral glands that produce substances related to the attraction and reward
of pollinators are crucial for the reproductive success of angiosperms. These
structures may include nectaries, osmophores, elaiophores, and resin glands and
are quite diverse in flowering plants. This chapter presents the diversity of
morphologies and substances produced by the floral glands and how they
improve the pollinator’s attraction. We also describe how some angiosperms
and floral visitors may have coevolved leading to specific pollination systems
in some groups of plants. The integration of morphological, chemical, and
ecological studies allows for a better understanding of the relationships that
evolved between flowers and pollinators along their evolutionary histories.
These comprehensive approaches provide opportunities to dissect the evolution
of secondary metabolites produced by specialized secretory structures in flowers,
including the origin and subsequent modification of these glands and their
produced compounds.
Keywords
Elaiophores · Flowering plants · Nectaries · Osmophores · Pollination · Resin
glands · Secretory structures
List of Abbreviations
CRC Crabs claw
ER
Endoplasmic reticulum
TS
Transversal section
1
Introduction
The majority of flowering plants rely on animals to transfer pollen grains from
one flower to another enabling successful reproduction [1, 2]. Pollinators visit the
flowers searching for resources used as nutrients, for breeding, or for the construction of nests. Therefore, flowering plants have developed different strategies for
attracting pollinators, such as a variety of colors, shapes, and/or the production of
resources by specialized structures [3, 4].
The main specialized structures present in flowers are glands (secretory structures), which produce attractants or resources for the visitors. The relationship
710
E. D. Tölke et al.
5.1 Resins Produced by Flowers and Inflorescences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735
5.2 Resin Glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 736
5.3 Floral Resin: Characteristics and Histochemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 738
5.4 The Evolution of Floral Resin Glands Related to Pollination . . . . . . . . . . . . . . . . . . . . . . . 739
6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 739
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740
Abstract
Floral glands that produce substances related to the attraction and reward
of pollinators are crucial for the reproductive success of angiosperms. These
structures may include nectaries, osmophores, elaiophores, and resin glands and
are quite diverse in flowering plants. This chapter presents the diversity of
morphologies and substances produced by the floral glands and how they
improve the pollinator’s attraction. We also describe how some angiosperms
and floral visitors may have coevolved leading to specific pollination systems
in some groups of plants. The integration of morphological, chemical, and
ecological studies allows for a better understanding of the relationships that
evolved between flowers and pollinators along their evolutionary histories.
These comprehensive approaches provide opportunities to dissect the evolution
of secondary metabolites produced by specialized secretory structures in flowers,
including the origin and subsequent modification of these glands and their
produced compounds.
Keywords
Elaiophores · Flowering plants · Nectaries · Osmophores · Pollination · Resin
glands · Secretory structures
List of Abbreviations
CRC Crabs claw
ER
Endoplasmic reticulum
TS
Transversal section
1
Introduction
The majority of flowering plants rely on animals to transfer pollen grains from
one flower to another enabling successful reproduction [1, 2]. Pollinators visit the
flowers searching for resources used as nutrients, for breeding, or for the construction of nests. Therefore, flowering plants have developed different strategies for
attracting pollinators, such as a variety of colors, shapes, and/or the production of
resources by specialized structures [3, 4].
The main specialized structures present in flowers are glands (secretory structures), which produce attractants or resources for the visitors. The relationship
710
E. D. Tölke et al.