Adnan Akcin

Effect of salinity stress on chlorophyll, carotenoid content, and proline in Salicornia prostrata Pall. and Suaeda prostrata Pall. subsp. prostrata (Amaranthaceae)

Salicornia prostrata Pall. and Suaeda prostrata Pall. subsp. prostrata occur together on saline soils in Kızılırmak Delta in Samsun, Turkey. The effects of salinity stress on photosynthetic pigments and proline were investigated in these two species in natural habitats. With the increasing soil salinity, a decrease in chlorophyll (Chl) and carotenoid contents was observed in both taxa. However, in Salicornia prostrata, photosynthetic pigments levels were lower than those in Suaeda prostrata. Proline contents significantly increase with increase in salinity level in both species, whereas Salicornia prostrata produced less proline than Suaeda prostrata. Proline and Chl a contents were significantly different betweesn examined species according to soil salinity. Based on obtained data, we can conclude that at in situ conditions, Salicornia prostrata is more salt tolerant compared with Suaeda prostrata.

Antimicrobial and Antioxidant Activity of the Essential Oil of the Turkish Endemic Species Achillea phrygia Boiss. & Bal.

Abstract The essential oil obtained from the dried flowering aerial parts of Achillea phrygia Boiss & Bal. by hydrodistilation was analysed by gas chromotography-mass spectrometry. Camphor (35.55 %), 2- furaldehyde (16.59 %) and 1,8-cineol (eucalyptol) (10.12 %) were detected as the major components of the essential oil. Essential oil of the plant was also tested for antimicrobial activity using the disc-diffusion method against 6 reference bacterial strains and 65 clinical bacterial isolates. Essential oil of A. phrygia showed antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), Acinetobacter baumannii and bacterial strains as S. aureus ATCC 25923, S. aureus ATCC 43300, Acinetobacter baumannii ATCC 19606. In additionally, the essential oil were not effective against bacterial strains as Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212. Morover, the total antioxidant capacity and the scavenging effect on 2,2diphenil-1-picrylhydrazyl (DPPH) radicals of the essential oil were also evaluated. The radical scavenging activity of A. phrygia essential oil was 40.43 %.

Anatomical Adaptations to Salinity in Spergularia marina (Caryophyllaceae) from Turkey

The present paper deals with the salt effect on root, stem and leaf anatomy of Spergularia marina. Salt tolerant populations of Spergularia marina from low (2.0–4.2 dS/m), medium (9.3–10.7 dS/m) and highly (18.4–26.2 dS/m) saline soils were evaluated for anatomical modifications. Root anatomical characteristics as cortex thickness and xylem vessel diameter were decreased in high saline environments. Increased aerenchyma and periderm thickness in the root were critical for checking water loss and enhancing water storage capability. In stem, higher salinity decreased the thickness of the epidermis and cortex. Increased aerenchyma and increased thickness of vascular tissue seemed to be crucial for its better survival under saline environments. The thickness of sclerenchyma was unchanged under low and moderate salinity but considerably increased under high salinity. Leaf anatomy shows that salt stress resulted in an increase of cuticle and parenchyma thickness as well as an increase of vascular bundle sheath thickness. The presence of the cells with calcium oxalate crystals in the stem and leaf increased at higher salinity. Additionally, under high salinity it was observed that both stomatal index and stomatal dimensions were considerably reduced. These results show that salinity stress shows significant anatomical modifications in Spergularia marina.

Chemical Composition and Antimicrobial Activity of the Essential Oil of Endemic Heracleum platytaenium Boiss. from Turkey

The compositions of the essential oil of Heracleum platytaenium Boiss. aerial parts, grown in Turkey were determined by GC-MS. Twenty-two compounds (95.24 %) were determined. The major compounds in the oil were found to be octyl acetate (85.53 %), octyl hexanoate (3.06 %), (Z)-4-octenyl acetate (1.60 %) and octyl octanoate (1.24 %). The antimicrobial activity of essential oil extracted from H. platytaenium against various yeast and bacteria species using the disc diffusion method was investigated during the present study. The extract exhibited strong antimicrobial activity against Candida glabrata with inhibition zones varying between 12-32 mm. In contrast, the growth of all the tested bacteria were not affected by the extract. In conclusion, this study confirms that H. platytaenium essential oil could be considered as a natural anticandidal source.

Effects of Grazing on Soil Parameters in Meadow Ecosystems

Bu çalışma Samsun-Türkiye’de alüvyal delta ovalarındaki çayır ekosistemlerinde otlatmanın toprak parametrelerine etkilerini belirlemek için yürütülmüştür. 2000-2003 yıllarında 5×5 m lik beş adet eksklosür çalışma alanında floristik bileşim ve habitat koşulları bakımından homojen alanlarda kurulmuştur. Toprak örnekleri eksklosürlerin içerisinden ve dışından olmak üzere en üst toprak yüzeyi uzaklaştırıldıktan sonra 20 cm derinlikten bir yıl boyunca aylık olarak alınmıştır. Toprak organik maddesi, pH, azot, fosfor, potasyum, CaCO 3 ve toplam tuzluluk standart yöntemlerle ölçülmüştür. Genellikle CaCO 3 ve toplam tuzluluk otlatılan ve korunan kısımlar arasında istatistiksel olarak önemli derecede farklı çıkmıştır.