This study was aimed to determine the responses of some sunflower hybrids to drought and low temperature stresses during germination and seedling development period. Sunflower hybrids of Sanbro MR, 63LE113, 64LL62 and Meteor were used in the study. Germination percentage, mean germination time, root and shoot length, root / shoot ratio, seedling fresh and dry weight of the sunflower hybrids were investigated at two temperatures (low 15°C and optimum 25°C) and drought stresses (distilled water, -1.5, -3.0, -4.5 and -6.0 bar) induced by polyethylene glycol 6000. The results of the research showed that there were significant differences among the sunflower hybrids in terms of the investigated characteristics. Increased drought stresses led to decreasing germination percentage, root and shoot length, seedling fresh weight, but caused a prolonged germination time and increased seedling dry weight. No significant change was observed in the germination and seedling development of the sunflower up to drought of -3,0 bar. The root / shoot ratio of sunflower hybrids increased at 15°C. The Sanbro MR had the fastest and highest germination along with the highest seedling fresh and dry weight at low temperature and higher drought stresses. It was concluded that sunflower hybrid Sanbro MR gave better performance under drought and low temperature conditions than the other hybrids.

This study was aimed to determine the responses of some sunflower hybrids to drought and low temperature stresses during germination and seedling development period. Sunflower hybrids of Sanbro MR, 63LE113, 64LL62 and Meteor were used in the study. Germination percentage, mean germination time, root and shoot length, root / shoot ratio, seedling fresh and dry weight of the sunflower hybrids were investigated at two temperatures (low 15°C and optimum 25°C) and drought stresses (distilled water, -1.5, -3.0, -4.5 and -6.0 bar) induced by polyethylene glycol 6000. The results of the research showed that there were significant differences among the sunflower hybrids in terms of the investigated characteristics. Increased drought stresses led to decreasing germination percentage, root and shoot length, seedling fresh weight, but caused a prolonged germination time and increased seedling dry weight. No significant change was observed in the germination and seedling development of the sunflower up to drought of -3,0 bar. The root / shoot ratio of sunflower hybrids increased at 15°C. The Sanbro MR had the fastest and highest germination along with the highest seedling fresh and dry weight at low temperature and higher drought stresses. It was concluded that sunflower hybrid Sanbro MR gave better performance under drought and low temperature conditions than the other hybrids.

Küresel ısınma nedeniyle ortaya çıkan su kıtlığı ağaçların büyümesini ve gelişmesini sınırlayarak kuraklık stresine neden olmaktadır. Türkiye’de doğal olarak yetişmekte olan Fagaceae familyasına ait kestane (Castanea sativa) kuraklıktan etkilenmektedir. Bu çalışmada Türkiye’nin Akdeniz bölgesinin üç farklı popülasyonundan (Akseki, İbradı ve Selge); Ege bölgesinden (İzmir-Ovacık), Marmara bölgesinden (Bursa) ve Karadeniz bölgesinden (Düzce) toplanan C. sativa tohumlarından elde edilen fidanlar kullanılmıştır. Sera ortamında farklı sulama rejimlerine tabi tutulan üç yaşında (3+0) kestane fidanlarının kuraklık stresi altındaki yaprak gaz değişim parametreleri [net asimilasyon (fotosentez) oranı (A), stoma iletkenliği (gs), terleme miktarı (E), içsel su kullanım etkinliği (iWUE=A/gs) ve anlık bitki su kullanım etkinliği (WUE=A/E)] ve prolin birikimine etkisi araştırılmıştır. Sonuç olarak, bütün popülasyonların E, A, gs değerlerinin kontrol gruplarına göre önemli ölçüde azalmasının yanı sıra prolin birikiminin kontrol gruplarına göre arttığı gözlenmiştir. Sonuç olarak altı farklı C. sativa popülasyonlarının kuraklığa adaptasyon potansiyellerinin değişkenlik gösterdiği ancak Akdeniz popülasyonlarının kuraklığa adaptasyon potansiyellerinin daha yüksek olabileceği gözlenmiştir.

Çalışma, endofit bakteri uygulamalarının farklı kuraklık stresi altında yetiştirilen biber fidelerinin gelişimi üzerine etkisini ortaya koyabilmek amacıyla, kontrollü koşullarda saksı denemesi şeklinde yürütülmüştür. Biber çeşidi olarak Mostar F1; endofit bakteri olarak da Ochrobactrum sp. (CB36/1) ve Bacillus sp. (CA41/1)) izolatları uygulanmıştır. Bakteri uygulaması, 109 cfu/ml yoğunluğunda iki kez (ilk uygulama 10 ml- ikinci uygulama 15 ml) yapılmıştır. Tohum ekiminden itibaren, 52 gün boyunca tüm saksılar düzenli olarak sulanmıştır. Kontrol (B0) uygulamalarında sulamalara 2 gün aralıklar ile devam edilmiş; ikinci uygulamada (B1) dört günlük bir kuraklık stresi ve son uygulamada (B2) ise 8 günlük bir kuraklık stresi uygulanmıştır. Bitki gelişim parametreleri olarak; gövde çapı, sürgün boyu ve kök uzunluğu, sürgün yaş ve sürgün kuru ağırlığı, yaprak sayısı, kök yaş ve kök kuru ağırlığı incelenmiştir. B1 ve B2 stres uygulamalarının, bitki gelişimine etkisinin genel olarak olumsuz olduğu tespit edilmiştir. Endofit bakterileri uygulamalarının ise farklı kuraklık streslerinin yol açtığı olumsuzluğa karşı nispeten olumlu düzeyde etkilere sahip olduğu belirlenmiştir.

Çalışma, endofit bakteri uygulamalarının farklı kuraklık stresi altında yetiştirilen biber fidelerinin gelişimi üzerine etkisini ortaya koyabilmek amacıyla, kontrollü koşullarda saksı denemesi şeklinde yürütülmüştür. Biber çeşidi olarak Mostar F1; endofit bakteri olarak da Ochrobactrum sp. (CB36/1) ve Bacillus sp. (CA41/1)) izolatları uygulanmıştır. Bakteri uygulaması, 109 cfu/ml yoğunluğunda iki kez (ilk uygulama 10 ml- ikinci uygulama 15 ml) yapılmıştır. Tohum ekiminden itibaren, 52 gün boyunca tüm saksılar düzenli olarak sulanmıştır. Kontrol (B0) uygulamalarında sulamalara 2 gün aralıklar ile devam edilmiş; ikinci uygulamada (B1) dört günlük bir kuraklık stresi ve son uygulamada (B2) ise 8 günlük bir kuraklık stresi uygulanmıştır. Bitki gelişim parametreleri olarak; gövde çapı, sürgün boyu ve kök uzunluğu, sürgün yaş ve sürgün kuru ağırlığı, yaprak sayısı, kök yaş ve kök kuru ağırlığı incelenmiştir. B1 ve B2 stres uygulamalarının, bitki gelişimine etkisinin genel olarak olumsuz olduğu tespit edilmiştir. Endofit bakterileri uygulamalarının ise farklı kuraklık streslerinin yol açtığı olumsuzluğa karşı nispeten olumlu düzeyde etkilere sahip olduğu belirlenmiştir.

Drought stress is one of the most serious abiotic stresses that cause a reduction in plant growth, development and yield in the world. The aim of this study is to reveal the morphological, physiological and biochemical responses of the Demre pepper variety and nine different pepper genotypes against drought stress. Pepper seeds were planted into trays containing peat: perlite (2: 1) mixture. Then, seedlings having two leaves were transferred to plastic pots containing mixture of peat:perlite (2:1) mixture. Drought stress application was started when the plants have four leaves. The control plants were irrigated with nutrition solution. Genotypes were classified according to the severity of leaf damage symptoms by using 0-5 scale. In addition, shoot fresh and dry weight, plant height, stem diameter, leaf number, leaf area, relative water content (RWC), membrane injury index (MII), potassium (K) and calcium (Ca) concentration of shoot, malondialdehyde content (MDA), total chlorophyll and carotenoid, total flavonoid and phenolic content, anitoxidative enzyme activities (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX)) were also determined. As a result of the study, it was determined that drought had negative effect in terms of morphological and physiological parameters, and this effect revealed differences among genotypes. While drought stress increased MDA and antioxidative enzyme activity, BIB-6 and BIB-8 genotypes were found to be the most tolerant genotypes among the genotypes examined.

The aim of the study is to determine the seed quality of different dry bean genotypes, grown under full and limited irrigation conditions. The study was conducted at Nigde Omer Halisdemir University laboratories. Eight different dry bean cultivars (Yunus 90, Cihan, Goynuk 98, Batalla, Alberto, Arslan, Zirve, Noyanbey 98) were used in the study. The study was established with 3 replications according to randomized split-plot design. Quality characters like dry and wet seed weight, water uptake capacity, water uptake index, dry and wet volume, swelling capacity and swelling index, cooking time and protein content were determined. In conclusion, statistically significant differences among applications and cultivars were observed in terms of the all parameters examined. The grains obtained from the limited irrigation plots, had lower values in terms of all evaluated properties. Differences between dry and wet weight, water uptake capacity and index, dry and wet volume, cooking time and protein content between cultivars were statistically significant. In the study, correlation between cooking time and grain size was determined, and it was concluded that enlarging in grains size increases the cooking time. In addition, it was concluded that limited irrigation in the reproductive period had a negative effect on seed quality of different dry bean cultivars and it should not be lowered below 50% of the water capacity in the soil during this period.

The study aimed to identify physiological response of potato to drought. For this aim, a drought experiment was carried out by using two different potato varieties, cv. Desiree and Russet Burbank, under environmentally controlled greenhouse conditions. Drought treatment was initiated at 45 days after emergence (early tuber bulking period) by withholding irrigation for 10 days. Physiological traits such as stomatal conductance, transpiration rate, photosynthetic rate, chlorophyll index, leaf temperature, proline content, malondialdehyde (MDA) accumulation and hydrogen peroxide (H2O2) accumulation, in addition, some yield components average tuber weight, number of tubers and plant tuber yield were evaluated in the study. While the first significant decline in stomatal conductance, transpiration rate, and photosynthetic rate of both varieties was occurred at the 5th day of withholding irrigation, the highest decline was observed at 9th and 10th days of withholding irrigation. Proline content in both varieties increased two times at 10th day of withholding irrigation, however, H2O2 accumulation was not changed significantly by drought treatment. Even though MDA accumulation was increased in both varieties under drought stress conditions, the increase was significant in Desiree whereas, it was not significant in Russet Burbank. In addition, while drought treatment did not change the plant tuber yield in both varieties, it caused to a significant decline in average tuber yield of Russet Burbank, being an important trait for marketable tuber yield.

The study aimed to identify physiological response of potato to drought. For this aim, a drought experiment was carried out by using two different potato varieties, cv. Desiree and Russet Burbank, under environmentally controlled greenhouse conditions. Drought treatment was initiated at 45 days after emergence (early tuber bulking period) by withholding irrigation for 10 days. Physiological traits such as stomatal conductance, transpiration rate, photosynthetic rate, chlorophyll index, leaf temperature, proline content, malondialdehyde (MDA) accumulation and hydrogen peroxide (H2O2) accumulation, in addition, some yield components average tuber weight, number of tubers and plant tuber yield were evaluated in the study. While the first significant decline in stomatal conductance, transpiration rate, and photosynthetic rate of both varieties was occurred at the 5th day of withholding irrigation, the highest decline was observed at 9th and 10th days of withholding irrigation. Proline content in both varieties increased two times at 10th day of withholding irrigation, however, H2O2 accumulation was not changed significantly by drought treatment. Even though MDA accumulation was increased in both varieties under drought stress conditions, the increase was significant in Desiree whereas, it was not significant in Russet Burbank. In addition, while drought treatment did not change the plant tuber yield in both varieties, it caused to a significant decline in average tuber yield of Russet Burbank, being an important trait for marketable tuber yield.