Chapter 18 The Biology of Thalassia
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Fig. 1. Thalassia testudinum—specimen from Puerto Morelos reef lagoon, Mexican Caribbean. (A) General habit, showing a horizontal
rhizome with a foliage shoot which has formed a lateral branch; on the same rhizome section, a dormant shoot has also branched,
(B) Schematic drawing of rhizome section shown in A, (C) Detail of vertical rhizome showing initiation of branching, (D) Transverse
section through section (indicated by circle in C), the circles indicate location of the apical meristems (Safranin-fast green tinction,
amplification 10 × 1), (E) Lateral branch of a vertical rhizome, showing apex and juvenile shoot, (F). Transverse section through apex
of a foliar shoot showing details of the apex (zone indicated by circle in E; Fuelgen tinction, amplification 10 × 4), (G) Dormant shoot;
note unilateral position of the roots, (H) Transverse section of the apex of a dormant shoot, note that the scale-like leaves are folded
over the meristem (Fuelgen tinction, amplification 10 × 10), (I) Transverse section through dormant shoot in another plane, showing
root primordium (Fuelgen tinction, amplification 10 × 10). M: meristem, P: leaf (or scale) primordium, numbers are assigned in order
of development, P1 being the youngest. SQ: squamule, RP: Root Primordium. (Nomenclature follows Tomlinson and Vargo, 1966 and
van Tussenbroek et al., 2000). Lines in the histological sections represent 0.2 mm. Figs. D, F, H, and I with technical assistance of J.G.R.
Wong and C.A. Galindo Rosete.
417
Fig. 1. Thalassia testudinum—specimen from Puerto Morelos reef lagoon, Mexican Caribbean. (A) General habit, showing a horizontal
rhizome with a foliage shoot which has formed a lateral branch; on the same rhizome section, a dormant shoot has also branched,
(B) Schematic drawing of rhizome section shown in A, (C) Detail of vertical rhizome showing initiation of branching, (D) Transverse
section through section (indicated by circle in C), the circles indicate location of the apical meristems (Safranin-fast green tinction,
amplification 10 × 1), (E) Lateral branch of a vertical rhizome, showing apex and juvenile shoot, (F). Transverse section through apex
of a foliar shoot showing details of the apex (zone indicated by circle in E; Fuelgen tinction, amplification 10 × 4), (G) Dormant shoot;
note unilateral position of the roots, (H) Transverse section of the apex of a dormant shoot, note that the scale-like leaves are folded
over the meristem (Fuelgen tinction, amplification 10 × 10), (I) Transverse section through dormant shoot in another plane, showing
root primordium (Fuelgen tinction, amplification 10 × 10). M: meristem, P: leaf (or scale) primordium, numbers are assigned in order
of development, P1 being the youngest. SQ: squamule, RP: Root Primordium. (Nomenclature follows Tomlinson and Vargo, 1966 and
van Tussenbroek et al., 2000). Lines in the histological sections represent 0.2 mm. Figs. D, F, H, and I with technical assistance of J.G.R.
Wong and C.A. Galindo Rosete.