Emine Atalay

Mechanisms of boron tolerance and accumulation in plants: a physiological comparison of the extremely boron-tolerant plant species, Puccinellia distans, with the moderately boron-tolerant Gypsophila arrostil.

The physiological characteristics of the extremely boron (B)-tolerant plant species, Puccinellia distans, were compared with those of the moderately tolerant Gypsophila arrostil, two species collected from a B-mining area of Eskişehir, Turkey. Boron was supplied to plants hydroponically at B concentrations ranging from 0.5 to 50 mg B/L for G. arrostil, and from 0.5 to 2000 mg B/L for P. distans. The results show that P. distans has a strikingly greater tolerance to B than G. arrostil. While G. arrostil was unable to survive B supply concentrations greater than 50 mg B/L, P. distans grew at B supply concentrations exceeding 1250 mg B/L. Our research supports the conclusion that from 0.5 to 50 mg B/L, P. distans is better able to restrict the accumulation of B in the whole plant, and the transport of B from root to shoot, than G. arrostil. We propose that P. distans uses several strategies to achieve B tolerance including the ability to restrict the accumulation of B relative to its accumulation of biomass, the ability to restrict the transport of B from root to shoot, and, to a lesser extent, the ability to tolerate high concentrations of B in its shoot and root tissues.

Endemik Astragalus trojanus Stev’in Nodal Kültür ile Mikroçoğaltımı

Bu arastirmada, tibbi ozelliklere sahip endemik Astragalus trojanus Stev. bitkisinin nodal kulturler ile klonal cogaltimi amaclanmistir. Tohumlar Murashige ve Skoog (MS) besin ortaminda cimlendirilmis ve elde edilen steril fidelerin nodal segmentleri eksplant olarak kullanilmistir. Ilk olarak MS ve Woody Plant Medium (WPM) besin ortamlarinin surgun cogaltimina etkileri arastirilmistir. Eksplantlar farkli konsantrasyonlarda (0.2, 0.5, 1.0, 2.0 mg/L) 6-benzil amino purin (BAP) iceren MS ya da WPM besin ortamlarinda kulture alinmistir. Kulturden 4 hafta sonra en fazla surgun sayisi (2.80 adet/eksplant) 0.5 mg/L BAP iceren WPM ortaminda elde edilmistir. Calismanin devaminda nodal segmentler, sitokinin kaynagi ve konsantrasyonlarinin surgun cogaltimina etkisini belirlemek amaciyla BAP, thidiazuron (TDZ), kinetin (KIN)’in farkli konsantrasyonlarini (0.2, 0.5, 1.0, 2.0 mg/L) iceren WPM temel besin ortaminda kulture alinmistir. 4 hafta sonunda elde edilen surgun sayilari bakimindan TDZ ve KIN’in benzer etki gosterdigi, en yuksek surgun sayisinin (2.09 adet/eksplant) BAP’dan elde edildigi tespit edilmistir. Rejenere surgunler koklenme icin 1 veya 3 mg/L indol-3-butirik asit (IBA), naftalen asetik asit (NAA) veya indol-3-asetik asit (IAA) iceren WPM ortamlarina aktarilmistir. Kulturden 4 hafta sonra en yuksek koklenme yuzdesi (%80) 3 mg/L IBA iceren WPM ortamindan elde edilirken, en fazla kok sayisi (4.33 adet/eskplant) 3 mg/L IAA iceren WPM ortamindan elde edilmistir. Koklenen bitkicikler 1:1 oraninda torf ve perlit iceren plastik bardaklara aktarilarak dis ortama basariyla alistirilmis ve tam bitki gelisimi 15 hafta sonunda tamamlanmistir. Bu arastirma ile, Astragalus trojanus Stev. endemik turunde etkili bir klonal cogaltim metodu tanimlanmistir.