Vascular tissue
Subnectary
parenchyma
Nectary
parenchyma
Epidermis
Cuticle
Stomata
4
1
2
3
5
7
6
Mitochondrion
Chloroplast
Pl w/ starch
Dictyosome
Vacuole
Nucleus
Rough ER
Sugars/Nectar
Symplast route
Apoplast route
Fig. 4 Nectar production, storage, and secretion. Nectar production may occur through
different mechanisms: (1) production in nectary parenchyma by the organelles therein, such
as rough endoplasmic reticulum and chloroplasts. Afterward the nectar may be modified by
the enzymes present in the cytoplasm and stored in vacuoles; (2) production from the
sucrose of the phloem. (3) The sucrose may be broken down into glucose and fructose,
further modified, and transported outside the nectary or (4) may be stored first in
amyloplasts and/or vacuoles. The secretion of nectar may be released (5) through
granulocrine or (6) eccrine mechanism or (7) by nectarostomata. The representation of
the three mechanisms in the same schematic drawing does not imply that all these mechanisms
occur simultaneously
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E. D. Tölke et al.