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Glandular and non-glandular hairs in the seasonally dimorphic Origanum dictamnus L. (Lamiaceae) as a means of adaptation to cold stress

100%

Bosabalidis A. M., Sawidis T.

Acta Agrobotanica

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2014

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tom 67

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nr 1

Origanum dictamnus is a seasonally dimorphic plant having different appearance in winter and summer. Shoots of winter plants are leaf-naked except for their apical region which bears a cluster of small leaves covered with a thick indumentum of non-glandular hairs. This indumentum highly contributes to the avoidance of cold penetration into the leaf mesophyll, allowing thus plants to endure winter low temperatures. Shoots of summer plants are vigorous with large green leaves. Non-glandular hairs are dendroid with a 5-celled vertical stub and several lateral branches. Glandular hairs are of two types, large peltate hairs and small capitate hairs. Peltate hairs are numerous and consist of a 12-celled head, a unicellular stalk, and a basal epidermal cell.. They constitute the sites of essential oil secretion. Capitate hairs occur in a small number and are composed of a unicellular head, a unicellular stalk and a basal epidermal cell. They are not secreting essential oil, but a hydrophilic material. The oil secreted by the peltate hairs has antioxidant properties, opposes the oxidative stress resulted from low temperatures, and contributes to the adaptation of the plant to winter cold stress.

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Seasonal distribution of phenolics in leaves of aromatic plants (Origanum vulgare L., Mentha spicata L., Clinopodium vulgare L.) and their ecophysiological implications

100%

Kofidis G., Bosabalidis A. M.

Biological Letters

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2012

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tom 49

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nr 1

3

Leaf anatomy and chloroplast ultrastructure of Mn-deficient orange plants

81%

Papadakis I. E., Bosabalidis A. M., Sotiropoulos T. E., Therios I. N.

Acta Physiologiae Plantarum

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2007

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tom 29

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nr 4

Leaf samples of Mn-deficient and Mn-sufficient (control) ‘Navelate’ orange plants grown in a greenhouse were taken to investigate the effects of Mn deficiency in leaf structure and chloroplast ultrastructure. Total leaf chlorophyll concentration was significantly lower in Mn-deficient plants than in control ones. Entire lamina thickness was not altered due to Mn deficiency. However, Mn deficiency resulted in disorganization of mesophyll cells, mainly of palisade parenchyma cells. The number of mesophyll chloroplasts per cellular area and their length were both affected negatively. The membranous system of chloroplasts was also disorganized. The percentages of starch grains and plastoglobuli per chloroplast of Mn-deficient leaves were significantly greater than those of control leaves.

4

Effects of chilling stress on leaf morphology, anatomy, ultrastructure, gas exchange, and essential oils in the seasonally dimorphic plant Teucrium polium (Lamiaceae)

71%

Lianopoulou V., Bosabalidis A. M., Patakas A., Lazari D., Panteris E.

Acta Physiologiae Plantarum

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2014

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tom 36

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nr 08

The Mediterranean region (and globally also other regions) is characterized by the presence of phryganic plants, i.e. subshrubs that grow under hot and arid environmental conditions. These plants are reported to be affected by summer drought stress. However, in the present study the phryganic plant Teucrium polium (mountain germander) appears to be affected by winter chilling stress rather than by summer drought stress in a specific area. Winter leaves of the plant are smaller and thicker compared to summer leaves, have more stomata and glandular hairs, and their chloroplasts are larger, more numerous, with voluminous starch grains. Moreover, epidermal and mesophyll cells of winter leaves contain in their vacuoles dark phenolics and calcium oxalate crystals. Summer leaves are devoid of vacuolar phenolics and their chloroplasts possess many large plastoglobuli. Leaf gas exchange parameters (photosynthesis, transpiration, stomatal conductance) are significantly higher in winter leaves. Concentrations of osmoprotectors (stress indicators) like proline and soluble sugars are similarly higher in winter leaves. Essential oil assessments showed a significantly higher oil yield of winter leaves compared to summer leaves. Percentages of the major oil components (linalool, terpinen-4-ol, germacrene D, and spathulenol) are remarkably higher in winter oils than in summer oils. In conclusion, low environmental temperatures (1–10°C) appear to decisively influence the structure and function of winter leaves compared to summer leaves. Winter plants undergo chilling stress to which they respond by developing various mechanical and chemical defensive strategies.

Ograniczanie wyników

2 Acta Physiologiae Plantarum

1 Acta Agrobotanica

1 Biological Letters

4 Bosabalidis A. M.

1 Kofidis G.

1 Lazari D.

1 Lianopoulou V.

1 Panteris E.

1 Papadakis I. E.

1 Patakas A.

1 Sawidis T.

1 Sotiropoulos T. E.

1 Therios I. N.

2 2014

1 2012

1 2007

Glandular and non-glandular hairs in the seasonally dimorphic Origanum dictamnus L. (Lamiaceae) as a means of adaptation to cold stress

Seasonal distribution of phenolics in leaves of aromatic plants (Origanum vulgare L., Mentha spicata L., Clinopodium vulgare L.) and their ecophysiological implications

Leaf anatomy and chloroplast ultrastructure of Mn-deficient orange plants

Effects of chilling stress on leaf morphology, anatomy, ultrastructure, gas exchange, and essential oils in the seasonally dimorphic plant Teucrium polium (Lamiaceae)