An experiment was conducted with laying hens to determine the effects of feeding excesses of methionine in a practical layer diet. One hundred and thirty two laying hens at 61 weeks of age were used for the experiment. Two body weight groups (light and heavy) and three levels of mehionine were assigned to six groups of laying hen in a 2x3 factorial design. The diets were a 16.5% crude protein corn and soybean meal positive control diet (0.33% methionine), and this diet fortified with 1.00% additional DL-Methionine or 1.50% additional DL-Methionine. The diets were fed ad libitum to the hens for 10 consecutive weeks of production. For the total production period, body weight gain, hen-day egg production, egg weight, egg mass, daily feed intake and feed conversion ratio were not significantly different among any of the treatments in the two body weight groups (P>0.05). The study indicated that considerable tolerance exists in laying hens for individual excesses of the DL-Methionine commonly used as supplement in poultry diets.

Salinity stress is one of the most important and common abiotic stress factors that cause significant physiological and metabolic changes in plants, negatively affecting plant growth and development, and causing decrease in product quality and quantity. The elucidation of the molecular control mechanisms associated with salt stress tolerance is based on the activation and /or inactivation of various stress-related genes. Salt Overly Sensitive (SOS) tolerance mechanism under salt stress is of great importance in terms of salt tolerance of the plants. Although this mechanism has been studied for many years, the physiological changes that the plants give as a result of mutation of the genes in the pathway under different levels of sodium chloride (NaCl) during development have not been examined comparatively. In this study, we found that the Arabidopsis thaliana sos1-1 mutant plant showed sensitivity to 10 mM NaCl while the sos3-1 and hkt1-1 mutants showed tolerance. The sos1-1, sos3-1 and hkt1-1 mutants showed increasing sensitivity when NaCl was applied beyon 50 mM of concentration. In addition, plants did not show significant sensitivity for 1 day of stress application, while significant effects were observed in plant root length when exposed to salinity for 3 to 4 days. Col-0, hkt1-1 and sos3-1 roots treated with low levels of NaCl for a short term were positively affected in length. In the light of these results, the amount and duration of salt stress is very critical in Arabidopsis thaliana's responses to the stress and determination of molecular tolerance pathways.

Endojen ve eksojen faktörlere bağlı olan bitki büyüme ve gelişmesi; kuraklık, tuz, yüksek ve düşük sıcaklık derecesi, radyasyon ve ağır metaller gibi abiyotik stres faktörlerinden büyük ölçüde etkilenmektedir. Bitkilerde stresle başa çıkma, olumsuz koşullarda hücre metabolizmasında değişikler yapılması ve savunma mekanizmalarının harekete geçirilmesi ile gerçekleşmektedir. Salisilik asit (SA) bitkilerde bu mekanizmaları harekete geçiren moleküllerden biri olup, özellikle patojen saldırılarına karşı cevap oluşturulmasında etkili olan, içsel bir bitki büyüme düzenleyicisidir. Fenolik bir bileşik olan ve bir bitki hormonu olarak da tanımlanan SA, stres koşulları altında sinyal molekülü olarak görev alarak bitkinin stres koşullarında oluşturduğu cevabı düzenlemekte ve hayatta kalmasını sağlamaktadır. Özellikle eksojen SA uygulamalarının bitkilerde patojenite ile ilişkili genleri aktive ederek hastalıklara direnç sağladığı bilinmektedir. Dışarıdan uygulanan SA’in biyotik stres faktörleri yanında abiyotik stres faktörlerine karşı da bitkinin toleransını artırdığını gösteren çok sayıda çalışma bulunmaktadır. Eksojen SA uygulamaları domates, biber, mısır ve fasulye gibi farklı bitkilerde uygulanmış ve tuz, yüksek ve düşük sıcaklık, kuraklık ve ağır metal streslerine cevap oluşturmada etkin olduğu belirlenmiştir. Buna karşın bazı çalışmalarda eksojen SA uygulamalarının bazı bitki türlerinde vejetatif ve biyokimyasal içeriklerde inhibe edici özelliğinin bulunduğunun gösterilmesi; SA etkilerinin uygulama dozu, bitki türü ve uygulanma şekline bağlı olarak değişebileceği sonucunu vermektedir.

Salinity stress is one of the most important and common abiotic stress factors that cause significant physiological and metabolic changes in plants, negatively affecting plant growth and development, and causing decrease in product quality and quantity. The elucidation of the molecular control mechanisms associated with salt stress tolerance is based on the activation and /or inactivation of various stress-related genes. Salt Overly Sensitive (SOS) tolerance mechanism under salt stress is of great importance in terms of salt tolerance of the plants. Although this mechanism has been studied for many years, the physiological changes that the plants give as a result of mutation of the genes in the pathway under different levels of sodium chloride (NaCl) during development have not been examined comparatively. In this study, we found that the Arabidopsis thaliana sos1-1 mutant plant showed sensitivity to 10 mM NaCl while the sos3-1 and hkt1-1 mutants showed tolerance. The sos1-1, sos3-1 and hkt1-1 mutants showed increasing sensitivity when NaCl was applied beyon 50 mM of concentration. In addition, plants did not show significant sensitivity for 1 day of stress application, while significant effects were observed in plant root length when exposed to salinity for 3 to 4 days. Col-0, hkt1-1 and sos3-1 roots treated with low levels of NaCl for a short term were positively affected in length. In the light of these results, the amount and duration of salt stress is very critical in Arabidopsis thaliana's responses to the stress and determination of molecular tolerance pathways.

An experiment was conducted with laying hens to determine the effects of feeding excesses of methionine in a practical layer diet. One hundred and thirty two laying hens at 61 weeks of age were used for the experiment. Two body weight groups (light and heavy) and three levels of mehionine were assigned to six groups of laying hen in a 2x3 factorial design. The diets were a 16.5% crude protein corn and soybean meal positive control diet (0.33% methionine), and this diet fortified with 1.00% additional DL-Methionine or 1.50% additional DL-Methionine. The diets were fed ad libitum to the hens for 10 consecutive weeks of production. For the total production period, body weight gain, hen-day egg production, egg weight, egg mass, daily feed intake and feed conversion ratio were not significantly different among any of the treatments in the two body weight groups (P>0.05). The study indicated that considerable tolerance exists in laying hens for individual excesses of the DL-Methionine commonly used as supplement in poultry diets.