modern research physics

---

Alkaloids are a large group of molecules with biological, physiological and chemical activities. Plants of the genus (Podophyllaceae) are the known sources of alkaloids. In the present study the amount of total alkaloids of tubers of from two different regions of Iran, Marivan - Sanandaj and of from Sanandaj -Naghadeh was determined by spectrophotometry, on the reaction of alkaloid with bromocresol green (BCG). Moreover, the effect of some characteristicts of the soil habitat such as, soil pH, total nitrogen, potassium, altitude, texture soil, and nitrate content of tubers on the amount from total alkaloids was measured. The results of data analysis showed the significant differences between total alkaloid content of Marivan (27.12 ±1.18 mg/g D.W) with Sanandaj  (17.42 ±0.77 mg/g D.W) and of Sanandaj (15.38 ±0.65 mg/g D.W) with Naghadeh (7.4 ±0.32 mg/g D.W). Also there was a significant difference between the species in different regions other than of Sanandaj (17.42 ±0.77 mg/g D.W) with of Sanandaj (15.38 ±0.65 mg/g D.W). Furthermore, the results show that nitrate content of was higher than that of. The soil texture of Sanandaj (L. armeniaca) was loam sand and soil of the rest regions was clay loam. All of soils were mildly alkaline. Results from the effect of environmental factors on the total alkaloid content showed that with increasing amount of total nitrogen and potassium of soil and nitrate content, total alkaloids will be reduced, whereas pH, texture soil and altitude had not significant influence on total alkaloid contents

---

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.