Maryam Madadkar Haghjou, Roya Mohammadkhani Pordanjani,
Volume 4, Issue 13 (Vol. 4, No. 13, 2015 2015)
Abstract
Abstract
As nitrogen source is a necessary element in structure and cell metabolism, studying of nitrogen source and its effect on growth and different behave of photosynthetic organisms has received much attention. In this study, the comparative effects of three nitrogen sources (KNO3, NH4Cl and KNO3+NH4Cl) have been studied on physiological properties of two Dunaliella species, as Dunaliella sp. isolated from Gave-Khooni salt marsh and D.bardawil-UTEX2538, in different salt concentrations (0.1, 0.5 and 3 M NaCl) and cell division, changes in Chl a, Chl b, total Chl, total carotenoid total protein and fresh weight of the cells has been assayed during 24 days. D. bardawil had higher rates in cell growth, and in both strains the highest growth rates were observed at 0.5 M, treated with KNO3.Most of decreases in the amount of measured substances were happened on 8th day of assays and increases in Chl a, Chl b and total Chl contents were occurred in higher salt concentrations (0.5 M and 3 M) treated with KNO3. The cells in 0.5 M had the least fresh weight with the highest cell division rate. In D. bardawil, NH4Cl caused decrease in growth only in 0.1 and 3 M on 8th day. But noticeable decreases in Chl a, Chl b, total Chl, beta carotene and total carotenoid along with an increase in protein amount in both strains were observed only in 3M. After decreases on 8th day, the amount of assayed substances, increased at 3M. KNO3+NH4Cl as nitrogen source improved cell condition compared to cells treated with NH4Cl. D. bardawil responded to nitrogen source more different from other species and some increases in pigment contents occurred on 16th day.
Overall, these results suggest that, NH4Cl make both species more sensitive to higher salt concentrations and after a short period of responses with decreased amount of pigments and arises in protein content, some increases could be a sign for coping with the new condition.
Ms Forough Akbari, Dr. Maryam Madadkar Haghjou,
Volume 7, Issue 24 (vol. 7, no. 24, 2018)
Abstract
One of the important goals of plant physiology in water ecosystems, is biomass and growth increment of green microalgae which led to access to their valuable production. In this regard, many factors are able to influence the increment and decrement of algal biomass. In this research different levels of vanillin (C8H8O3), as 0 (control), 10, 25, 40, 50, 70, 90 and 100 mg. L-1, were investigated during 24 days on cell number, fresh weight, dry weight and some of physiological indices (such as total sugar, reducing sugars, protein and photosynthetic pigments) in two algae, D. badawil-UTEX2538 and D. salina-UTEX200. All experiments were performed as completely randomized design (CRD) in three replications. The highest number of cells was observed at 25, 40 and 50 mg. L-1 vanillin treatments. In D. bardawil, maximum specific growth rate (SGR) and minimum doubling time (DT) of cells were observed at 50 mg. L-1 and in D. salina those were observed at 25 and 40 mg. L-1. Fresh weight, dry weight and total sugar were increased by the most of treatments, but protein and reducing sugars were decreased compared to control. Chl a, total Chl and total carotenoid were increased only in D. bardawil, but Chl b and beta carotene showed decrements. D. salina had a higher growth rate but lower content of protein, total sugar and reducing sugars than D. bardawil. Overall, in contrast to some of the previous researches, vanillin which has phenolic nature induced faster growth rate and cell division in algal suspensions and also in the most of the cases, it led to improvement of physiological indices.
