Leaf anatomy of the Mexican species of Greigia (Bromeliaceae).
Greigia belongs to subfamily Bromelioideae and includes 28 species of mainly South American natives. Mexico has three endemic taxa (Smith 1959); Greigia juareziana L. B. Sm. and G. oaxacana L. B. Sm. native to Oaxaca State and G. vanhyningii L. B. Sm. restricted to Veracruz State (Espejo-Serna and Lopez-Ferrari 1994).
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All three species are terrestrial and exhibit herbaceous (fig. 1) large to medium sized shoots bearing spirally arranged leaves bearing closely triangular blades with serrate margins. The scape is lateral, subsessile,simple or compound, capitate to subcapitate (fig. 2), and bears bisexual, sessile or subsessile flowers equipped with free sepals and fused fleshy petals. The filaments are fused (adnate) to the petals, the anthers basifixed, and the inferior ovary ripens into a berry.
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Mexican species of Greigia inhabit oak and coniferous forests, between 2,100 and 2,700 m. Plants are uncommon in culture, but they have ornamental potential by their showy rosette with evergreen foliage. They have a sweet edible fruit with similar flavor to pineapple, locally named "pinuelas" or "pinuelillas" (Espejo-Serna and Lopez-Ferrari 1998).
The goal of this work was to describe foliar anatomy of Mexican species of Greigia.
Samples of each species were collected and segments of the middle part of the blades were fixed in FAA (Sass 1961; Table 1). Samples were dehydrated in an alcohol series, and embedded in paraffin. Sections 15 to 20 [micro]m were cut with a rotatory microtome and stained with safranine-fast green. Epidermal peels were obtained using a 10 % solution of NaOH and NaCl and stained with safranine. For the cellular sizes the averages of 25 measurements are made. Vouchers are deposited in the Herbario Metropolitano of the Universidad Autonoma Metropolitana de Iztapalapa (UAMIZ).
Species studied have a similar leaf anatomy which is described next.
Epidermal cells are rectangular, parallel to the longitudinal axis of the leaf, adaxial cells of 35 to 43 [??] m length by 17-25 [??] m wide, the abaxial cells differentiate in costal and intercostal, the former of 30-40 [??] m length by 16-20 [??] m wide and the second of 26-34 [??] m length by 18-26 [??] m wide. The anticlinal walls (abaxial and adaxial) are thin, in U or [OMEGA] shape, each cell with a central silica body (fig. 3). Stomata of tetracytic type are present only in the intercostal region on abaxial surface, guard cells of 31-35 [??] m length (fig. 4); scanty to abundant scales (0.2-8 scales) are present in the intercostal region on abaxial surface, distributed in longitudinal and parallel rows. Scales of a single layer of randomly aligned cells, with a central region are not differentiated structurally from the peripheral cells (fig.5).
Cuticle of 5-7 [micro]m wide (thick) (adaxial and abaxial). Epidermis (abaxial and adaxial) of one layer of square cells with thick cell walls. There is a hypodermis of 1-2 layers of cells below the adaxial epidermis, with thickened lignified walls. Storage parenchyma (adaxial and abaxial) with isodiametric colorless large cells (fig. 6). Chlorenchyma (only adaxial) has smaller isodiametric cells than the storage parenchyma, it has many chloroplasts. Among vascular bundles there is a spongy parenchyma with lobate cells (fig. 7). Idioblasts with raphides in the storage parenchyma and chlorenchyma. Starch grains are present in the parenchymatic cells near to the vascular bundles, between chlorophyllous parenchyma and spongy parenchyma. Collateral vascular bundles (41-90) are located in the middle portion of the blade, with three order types. Those of first order of 179-213 [micro]m length by 116-135 [micro]m wide, those of second order of 111-125 [micro]m length by 68-89 [micro]m wide, those of third order of 72-84 [micro]m length by 52-69 [micro]m wide. A clerenchymatous sheath surrounds each vascular bundle. A cap of fibers is found in both ends as well as an external parenchymatic sheath (fig. 8). In the adaxial portion the caps of the bundles of first order have a length from 25 to 55 [micro]m, those of second order of 30-49 [micro]m and those of third order of 21-37 [micro]m; in the abaxial portion the caps of the bundles of first order have a 44-72 [micro]m length, those of second order of 81-122 [micro]m and those of third order of 78-114 [micro]m. Stomata abaxial occur at the same level of the other epidermal cells; guard cells with periclinal thickened cell walls. Subestomatal chamber present. Stalk cells are immersed in an inferior level of the epidermic cells (fig.9).
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The three Mexican species of Greigia had similar anatomical characteristics, no diagnostic character was identified to distinguish among them. The species present an inner structure similar to those reported for other genera of the Bromeliodeae subfamily (Aoyama and Sajo 2003; Proenca and Sajo 2004; Dutra da Cruz, Nogueira da Costa et al. 2005).
We thank Ana Rosa Lopez Ferrari, Rosa Cerros Tlatilpa and Teresa Terrazas Salgado for the revision and valuable comments to manuscript.
Aoyama, E. M. and M. G. Sajo (2003). "Estrutura foliar de Aechmea Ruiz & Pav. subgenero Lamprococcus (Beer) Baker e especies relacionadas (Bromeliaceae)." Rev. Brasil Bot. 26(4): 461-473.
Dutra da Cruz, M. S., A. C. Nogueira da Costa, et al. (2005). "Leaf anatomy of Hohenbergia ramageana Mez. (Bromeliaceae) from Restinga Habitat in Rio Grande do Norte State, Brazil." J. Brom. Soc. 55(2): 88-89.
Espejo-Serna, A. and A. R. Lopez-Ferrari (1994). Las monocotiledoneas mexicanas una sinopsis floristica. Bromeliaceae, Burmanniaceae, Calochortaceae y Cannaceae. Mexico, Consejo Nacional de la Flora de Mexico.
Espejo-Serna, A. and A. R. Lopez-Ferrari (1998). "Current floristic and phytogeographic knowledge of Mexican Bromeliaceae." Rev. Biol. Trop. 46: 493-513.
Proenca, S. L. and M. G. Sajo (2004). "Estrutura foliar de especies de Aechmea Ruiz & Pav. (Bromeliaceae) do Estado de Sao Paulo, Brasil." Acta Bot. Brasil 18(2): 319-331.
Sass, J. E. (1961). Botanical microtechnique, 3rd. edition. Ames, The Iowa State University Press.
Smith, L. B. (1959). "Three new Greigia from Mexico." J. Brom. Soc. 9(4): 51-53.
Jacqueline Ceja Romero (1) and Alicia Rojas Leal (2)
(1) Universidad Autonoma Metropolitana Iztapalapa, Division de Ciencias Biologicas y de la Salud, Departamento de Biologia, A. P. 55-535, C.P. 09340 Iztapalapa, D.F., Mexico.
(2) Universidad Nacional Autonoma de Mexico, Instituto de Biologia, Departamento de Botanica, Apartado Postal 70-233, C.P. 04510, Coyoacan, D. F., Mexico.
Table 1. Species studied. Taxa Colector Locality G. juareziana A. Espejo 6688 OAXACA: ca. 16 km UA-MIZ42942 despues de la desv. a San Pedro Yolox, rumbo a la Esperanza. Carretera Oaxaca- Tuxtepec. G. oaxacana A. Espejo 6689 UA- OAXACA: ca. 16 km MIZ42957 despues de la desv. a San Pedro Yolox, rumbo a la Esperanza. Carretera Oaxaca- Tuxtepec. G. juareziana A. Lopez-Ferrari OAXACA: 32 km 3096 UAMIZ 42947 despues de Capulalpan y 21 despues de La Trinidad, rumbo a Talea de Castro G. juaeziana A. Lopez-Ferrari OAXACA: 32 km despues 3097 UAMIZ 42949 de Calpulalpan y 21 despues de La Trinidad, rumbo a Talea de Castro G. vanhyningii A. Lopez-Ferrari VERACRUZ: 5.5 km 3110 UAMIZ 42958 sobre la brecha a Las Minas, a partir de la carretera Perote-Xalapa G. juareziana J. Ceja 1605 UAMIZ OAXACA: ca. 10 km 42952 despues de Talea de Castro. Ca. 1 km despues de la desv. a Santiago Lalopa, rumbo a Ixtlan.
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|Author:||Romero, Jacqueline Ceja; Leal, Alicia Rojas|
|Publication:||Journal of the Bromeliad Society|
|Date:||May 1, 2007|
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