فصلنامه زیست شناسی گیاهی ایران
سال هفتم شماره 2 (پیاپی 24، تابستان 1394)

Salsola richteri (chenopodiaceae) has been dispersed in desert areas of north and east of the Irano-Turanian region in Iran. In present study، physiological characteristics of S. richteri to drought stress are investigated. Sampling of the plant at flowering stage was performed in the Shahrakht and Boshrooyeh deserts، South Khorasan province، Iran. Relation of drought stress with proline، sodium، potassium، soluble protein، flavonoid concentration and acid phosphatase activity is compared in the two research areas. The results indicated that all of the mentioned parameters in the leaves of S. richteri collected in Boshrooyeh are more than those in Shahrakht. The less soil moisture and the high monthly mean temperature in Boshrooyeh made it a higher drought area comparing to Shahrakht. Therefore، the significant advantage in concentration of the compounds and more activity of acid phosphatase in the species growing in Boshrooyeh area may indicates a better physiological resistance of S. richteri to stress conditions.

Ion balance and osmotic regulation in plants to mitigate the effects of drought is possible with accumulation of osmolytes like proline and glycine betaine. Accordingly، in order to investigate the effect of mycorrhizal fungai species on the eco-physiological characteristics of hyssop، a factorial experimental based on randomized complete block design with three replications was conducted at the Research Farm of Agriculture and Natural Resources of West Azarbaijan in 2013. Experimental treatments included species of mycorrhizal fungi (Glomus mosseae، G. intraradices، G. fasiculatum، G. claroideum، Acaulospora longula and control without mycorrhiza) and four levels of irrigation (irrigation at 80، 70، 60 and 50% of field capacity). The results of ANOVA showed the significant interaction between water deficit and mycorrhizal fungi species on the concentrations of malondialdehyde (MDA)، glycine betaine، proline، total soluble carbohydrates and essential oil percent. The highest concentrations of malondialdehyde (MDA) (125 nmol/g fresh weight)، glycine betaine (2019 μm/g dry weight)، proline (111 μm/g fresh weight)، essential oil percentage (7. 29%) and total soluble carbohydrates (396. 7 mg/g dry weight) were obtained from plants inoculated by G. claroideum، A. longula، A. longula، G. fasiculatum and G. claroideum and irrigated at 50 and 60% field capacity، respectively. The concentration of malondialdehyde (MDA) biomarker was increased at non-mycorrhizal plants compared with mycorrhizal one. Overall، this study suggested that the mycorrhizal species were effective to reduce stress and water use efficiency.

Michauxia laevigata belongs to the Campanulaceae family and grows on Iran and some parts of Armenia. This study was conducted to introduce the plant and to investigate ecophysiological characteristics such as altitude، pH، EC، percent of humidity، soil phosphatase، and measurement of some trace elements in soil. In addition، we evaluated some physiological parameters of M. laevigata including photosynthetic pigments and prolin content in different organs at both vegetative and generative stages. Soil investigations revealed that the region had the extra amounts of some heavy metals such as Cr+2، Pb+2، As+2، Zn+2 and Cu+2 and its pH was about 8. The soil phosphatase was approximately 1571 µmol min-1. There was a positive correlation between the soil pH and the activity of soil phosphatase، while the negative one with the amount of EC. Also، the results exhibited that there was significant (P≤0. 05) difference only in Mg amount between generative and vegetative stages. It seems that M. laevigata grows in sandy soils with nearly high amount of pH and is capable to grow under high concentrations of heavy metals.

Soil salinity is a serious environmental problem in arid and semi-arid regions that have negative impacts on crop production. In this research، because of medicinal and nutritional importance of the garden cress (Lepidium sativum) plant، the interactive effects of salinity (225 mM NaCl) and ascorbic acid (1 mM) were evaluated on growth and its water relations. A completely randomized design with four replications was conducted under controlled conditions. The results showed that salinity decreased growth، relative water content، osmotic potential and soluble proteins and increased soluble sugars، amino acids and proline contents. Many of salinity damaged characteristic were improved by adding exogenous ascorbic acid to salty environment. Exogenous ascorbic acid alone، in comparison with control، enhanced the growth of garden cress by increasing relative water content، soluble sugars and soluble proteins contents. The results indicated that usage of ascorbic acid، as an antioxidant، reduced harmful effects of salinity stress and led to growth improvement in garden cress plants.

Copper (Cu) and zinc (Zn) are the important trace elements for plant growth، which also play key roles in many structural and biochemical function in plants. In this study، regarding the high importance of the Savory (Satureja hortensis) plants in pharmaceuticals and food industries، the effects of different levels of Cu and Zn on essential oils content، yield and composition of reference plant were undertaken to investigate. The employed treatments were considered as Cu (0، 5، 25 mg kg-1 soil from CuSO4. 5H2O) and Zn (0، 10، 50 mg kg-1 soil from ZnSO4. 2H2O) as well as their combination. Isolated essential oil (EO) was analyzed using GC and GC-MS apparatus. The results revealed that the highest and the lowest EO content and yield are obtained in Cu5Zn10 and Cu25Zn50 treatments، respectively. The GC-MS analysis showed that carvacrol، γ-terpinene، p-cymene and delta-3-carene are the main EO constituents and found in Cu5Zn10، Cu25Zn50، Cu25Zn10 and Cu5Zn0 treatments، respectively. The comparison of EO content، yield and compositions of plants treated with different Cu and Zn levels indicated that this characteristics and especially oxygenated monoterpenes value are increased with the low levels of employed elements and subsequently decreased with increasing the elements dosages.

Propagation of wild pistachio as a multipurpose woody species is a hard and tedious task. In this research، an effective in vitro protocol was developed for rapid proliferation of wild pistachio (Pistacia atlantica ssp. mutica) in MS medium supplemented with B5 vitamins and different growth regulators. Rooting of plantlets was tested by two treatments containing Rhizopon and IBA in ex vitro. With respect to the results، the nodal segments explants، produced the highest shoot frequency، leaf frequency and the tallest shoots. On the other hand، the tallest shoots were generated from shoot tip explant and medium containing of TDZ plus IAA. Both treatments (Rhizopon and IBA) led to a remarkable increase in the number of roots، root length and rooting percentage compared to the control. These results may be applied for rapid proliferation to spread the pistachio trees and shrubs that are difficult and time consuming.

Drought stress is one of the major constraints for production and yield of soybean (Glycine max). For this reason، identifying mechanisms associated with drought tolerance in soybean is very impotent for improving and increasing drought resistance by genetic engineering methods. In this study، the effect of drought on growth traits (plant height، fresh and dry weight of shoot and also fresh and dry weight of root) and enzyme activities of isocitrate dehydrogenase (ICDH)، phosphoenolpyruvate carboxylase (PEPC)، malate dehydrogenase (MDH)، glutamine synthetase (GS) and nitrate reductase (NR) were assessed in drought sensitive and tolerant cultivars of soybean. The results showed that growth indicators are higher in drought tolerant cultivar under water availability (control) and water deficient when compared with those of drought sensitive cultivar. An increase in the activity of ICDH was observed in both the cultivars under drought stress as compared with their respective control plants but this activity was higher in tolerant cultivar. The activities of PEPC، MDH، GS and NR were significantly decreased in drought sensitive cultivar whereas the activities of these enzymes were higher in another cultivar. In general، the results of this study showed different behavior in the activities of assayed enzymes in two sets of soybean cultivars differing in drought tolerance and also decline of the activities of these enzymes in drought sensitive cultivar due to water deficit stress may be one of the possible reasons for decreased growth of the soybean plants under drought.