Articles
FLORAL BIOLOGY STUDY OF ZIZIPHUS LOTUS L.
Article number
840_46
Pages
337 – 342
Language
English
Abstract
Ziziphus lotus L. is a very common species in Tunisia.
It is found mainly in the Mediterranean bioclimatic semi-arid and arid zones according to Emberger classification.
In the Central and the South of Tunisia, it contributes to the landscape formation.
It is usually bushy because of the sandy winds often occurring in these regions and the cattle grazing (goats, sheep and Arabian camels). It grows on deep clayey soils which are good for shrubbing.
It is considered as an ancient weed because formerly people could not uproot it with their usual means.
Its vegetative and reproductive apparatus were studied by using light microscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. Ziziphus is generally bushy but, the state tree can be seen (rarely). Foliage is deciduous and appears at the end of spring and during summer.
The leaves are glabrous with a thin cuticle but the whole plant (leaves, flowers, stems ) is filled with mucilage.
Flowers are usually pentamerous but sometimes 4, 6 and 7-merous ones were observed.
In anther development, there is an asynchronism in the meiosis development and in the release of microspores from anther loculi.
The tapetum is of the secretory type.
Its cell walls persist and form a bag surrounding the pollen grains before their dispersal.
Mature pollen grains are bicellular, tetraedric in shape, breviaxes, tricolporate, angulo-aperturate and oblate.
Exine is striato-rugulate.
Ectexine is columellar in the beginning and seems to become granular later.
The aperture is entirely built up during the tetrad stage.
Apertural intine thickens and forms a zwischenkörper rich with trabecula.
It pushes out the discontinuous and weak exine.
Ovary is inferior and the ovule has two integuments.
It is usually bicarpellate (rarely tricarpellate) and bilocular.
It contains frequently, only single anatropous ovule in each loculus.
Fruit is drupaceous.
It usually contains two seeds.
In conclusion, according to some available descriptions of the Rhamnaceae, Ziziphus lotus shares some morphological and anatomical characters with the other members such as 4 or 5-merous flowers, secretory tapetum, pollen 2-celled, 3-colporate and triangular, anatropous ovule and drupaceous fruit and some ultrastructural features adapted to drought.
Besides the abundant mucilage, other features shall be analysed for the understanding the leaf ultrastructure, with a thin cuticle and numerous naked stomata.
It is found mainly in the Mediterranean bioclimatic semi-arid and arid zones according to Emberger classification.
In the Central and the South of Tunisia, it contributes to the landscape formation.
It is usually bushy because of the sandy winds often occurring in these regions and the cattle grazing (goats, sheep and Arabian camels). It grows on deep clayey soils which are good for shrubbing.
It is considered as an ancient weed because formerly people could not uproot it with their usual means.
Its vegetative and reproductive apparatus were studied by using light microscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. Ziziphus is generally bushy but, the state tree can be seen (rarely). Foliage is deciduous and appears at the end of spring and during summer.
The leaves are glabrous with a thin cuticle but the whole plant (leaves, flowers, stems ) is filled with mucilage.
Flowers are usually pentamerous but sometimes 4, 6 and 7-merous ones were observed.
In anther development, there is an asynchronism in the meiosis development and in the release of microspores from anther loculi.
The tapetum is of the secretory type.
Its cell walls persist and form a bag surrounding the pollen grains before their dispersal.
Mature pollen grains are bicellular, tetraedric in shape, breviaxes, tricolporate, angulo-aperturate and oblate.
Exine is striato-rugulate.
Ectexine is columellar in the beginning and seems to become granular later.
The aperture is entirely built up during the tetrad stage.
Apertural intine thickens and forms a zwischenkörper rich with trabecula.
It pushes out the discontinuous and weak exine.
Ovary is inferior and the ovule has two integuments.
It is usually bicarpellate (rarely tricarpellate) and bilocular.
It contains frequently, only single anatropous ovule in each loculus.
Fruit is drupaceous.
It usually contains two seeds.
In conclusion, according to some available descriptions of the Rhamnaceae, Ziziphus lotus shares some morphological and anatomical characters with the other members such as 4 or 5-merous flowers, secretory tapetum, pollen 2-celled, 3-colporate and triangular, anatropous ovule and drupaceous fruit and some ultrastructural features adapted to drought.
Besides the abundant mucilage, other features shall be analysed for the understanding the leaf ultrastructure, with a thin cuticle and numerous naked stomata.
Publication
Authors
M.B. Nasri-Ayachi, M.A. Nabli
Keywords
Ziziphus lotus, floral biology
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