Volume 18, Issue 47 (4-2007)
Abstract
In a green house pot experiment, the effects of salinity and increasing levels of potassium supply on factors determining dry matter production of two barley cultivars(Reyhan and Afzal) were investigated, with regard to yield (Number of tillers and ears, dry weight of ears, straw, roots, thousand grain weight and leaf area). The plants were grown under four levels of potassium (K1= 0,K2=./25, K3 =./5 and K4=1 gr. K/Kg. soil) and 40mM NaCl in a randomized complete blocks design with four replication. The results indicated that by using of NaCl, the number of ears, dry weight of ears, thousand grain weight, biomass and leaf area increased, whereas dry weight of roots ,the number of tillers per plant ,duration of grain filling and maturity period in both cultivars decreased. Increasing of potassium supply significantly increased dry weight of shoots during vegetative growth, but during reproductive- and maturity growth had no marked influence on dry weight production. By increasing the levels of potassium accompanied with salinity no effects on above mentioned parameters were observed. This may be due to a high availability of potassium in the soil , which led to an increase in dry weight of the plant shoots.
Volume 18, Issue 56 (9-2006)
Abstract
Due to the importance of benthic cyanobacteria in nitrogen fixation in paddyfields, the physiological responses of Fischerella ambigua FS 18 to salinity (NaCl 0, 0.5 & 1%) were investigated. Results indicated that growth rate was higher in control and that NaCl did not inhibit growth of other treatments. Similar responses were seen in the case of other physiological processes. Chlorophyll was declined with increasing salinity. Phycobiliproteins (PBP), phycocyanin (PC) and allophycocyanin (APC) were at least in 0.5% but the differences were not significant. The light-saturated photosynthetic rate was higher in control and decreased with increasing in salinity. With respect to nitrogenase activity, the highest rate was in control and the cultures with higher growth rates reached to the maximum level at a shorter time. There was no significant difference between 0.5 and 1% in relation to nitrogenase activity.
