Mithat Nuri Gevrek

Studies on the Adaptation of Azolla mexicana in the Aegean and the Mediterranean Regions

abstract Azolla (Azolla anabaena) is an aquatic fern plant that can be used as a green manure and organic matter resource in many countries where irrigation water is not a problem. A. mexicana is one of the azolla species adapted to the environmental conditions of Izmir (Turkey). The objective of this research was to determine the adaptation and agronomic potential of azolla plants to the Mediterranean climate regions. The research was conducted at three locations (Izmir and Aydın located in the Aegean region and Antalya located in the Mediterranean region of Turkey) in 1999, 2000 and 2001. Fresh azolla was planted in April, May, June and October at the rate of 300 g m−2 at each application. The growing azolla plants were harvested 15 days after planting. The highest fresh yield (1481 g m−2) was obtained in April at Izmir. The total N, P, and K values were between 2.93-3.31 %, 0.43-0.54 % and 1.10-1.37 % at Izmir, Aydın, and Antalya, respectively. The shortest time to reach a two-fold increase was 3.53 days at Izmir based on the average of three years.

Physiological and Biochemical Responses of Achillea Millefolium Group-Related Cultivar Proa to Different Nitrogen Regimes

ABSTRACT In the present study the effect of different nitrogen amounts (0 g [N0], 0.45 g [N1], 0.9 g [N2] and 1.35 g N [N3] per pot, corresponding to 0 kg·ha−1, 50 kg·ha−1, 100 kg·ha−1 and 150 kg·ha−1 N application in field conditions) and application times (at sowing, vegetative stage and pre-bloom stage) on the yield, relative water content, total nitrogen content and nitrogen use efficiency in plants of the Achillea millefolium group-related cv. Proa was investigated. Antioxidant activity, flavonoid content, rate and composition of the essential oils were also determined. Application of N2 increased the dry herbage and flos production, total nitrogen amount and nitrogen use efficiency, without affecting the essential oil rate while reducing the antioxidant activity. Higher amounts (N3] of nitrogen maintained the dry herbage and flos yield at levels similar to N2 but decreased the antioxidant activity and rate of the essential oil. The major component of the essential oil, chamazulene, was negatively (N1, N2) or not influenced (N3] by the nitrogen application, while variable changes were registered in the content of the other components. The data point to the nitrogen regime being a subtle tool for regulating the performance of cv. Proa plants.