گلناز تجدد

Ajowan, belonging to Apiaceae, is one of the most medicinal plants in Iran and is naturally distributed in Ethiopia, Egypt, and India. Despite the homogeneity of flower characteristics in the family, nevertheless, a high diversity of flower morphology can be seen in this genus. Given the pharmacological importance of Ajowan, the developmental stages of its male and female organs were examined.

Flower buds in different developmental stages were harvested, fixed in FAA, and maintained in 70% Ethanol. After performing various steps, including clarification and embedding in paraffin, microtomy sections were made. The Hematoxylin-eosin was used to stain the slices.

Based on the results, the initiation pattern of floral organ development is acropetal, in which the sepals initiate first, followed by petals, and finally, stamens. Initiation of gynoecium occurs with delay to the stamen. Isostemonous stamens, secretory tapetum layer, tetrahedral microspore tetrad, spindle shape microspores, mature pollen with two-celled and three germinal furrows. Asynchrony of microspore development was observed in the anthers of the same plant flowers and the pollen sacs of the same anther. Also, the development of male and female gametophytes was not synchronized in the same flower. Inferior ovary, anatropous ovules, the linear type of megaspore tetrad, polygonum type of functional megaspore formation and embryo sac development are other characteristics of this plant.

Advances in the world are causing changes in the living conditions of living things, including plants. Plants must be able to adapt to environmental stressful conditions in a variety of ways, even molecular methods. One mechanism is to regulate gene expression after transcription by miRNAs (microRNAs). MicroRNAs often have 20 to 22 nucleotides, some of whose target genes belong to transcription factors. The expression of microRNAs changes in response to dehydration stress. In the present study, Narcissus bulbs were grown under different irrigation conditions (from once a week to once every two months). The leaves of 60-day-old plants were used to extract the target gene of microRNA 159, MYB and the target gene of microRNA 172, AP2, by qPCR method. The results showed a significant increase in the expression of MYB and AP2 genes and no expression of 159 and 172 microRNAs in the treated and control samples. Therefore, miR172-miR159 is not affected by dehydration stress. Given that the expression of dehydration genes has been evaluated for the first time in the Narcissus pseudonarcissus, therefore, this study can provide a good basis for further investigation in this case.

Due to its great medicinal value, the Moldavian dragonhead, belonging to Lamiaceae, is naturally distributed in Europe, Siberia, and Central Asia and planted in different Iranian provinces. This research studied the development of male/female reproductive organs. Flowers and buds in different stages of development were fixed and preserved in order to prepare microtome sections using appropriate solutions and embed them in paraffin. Hematoxylin-eosin was used to stain the slices. Based on the results, despite the relative simultaneity of the formation of stamen primordium and carpel, stamens develop faster than ovules. Nurses’ cells in secretory and plasmodium types are rectangular, spindle-shaped, and often mononuclear or more. The microspore’s tetrads had tetrahedral ornamentations, and mature pollen grains were hexacolpate with reticulate ornamentation of the exine. The ovules were anatropous, unitegmic, and tenuinucellate. The functional megaspore has a micropillar position, and the embryo sac development belongs to the Polygonum type.

Phytoremediation is one of the available techniques for removing the volatile organic compound from the air. Benzene and toluene are volatile organic compounds that exist in many occupational environments. Plants are able to reduce benzene and toluene in the air and the use of plants is a simple and consistent solution for the nature to reduce these compositions in the air and improve the air quality of work environments. The phytoremediation potential of Dannae racemosa and Hedera helix were evaluated for remediation of benzene and toluene in air.

Dannae racemosa and Hedera helix  were exposed to exposed benzene(250ppm) and toluene(250ppm) each time alone in a chamber and to examine the decrease amount of benzene and toluene during 6 days. Then plants were exposed to 250ppm and 250ppm of benzene three times with a rest day and the processes of reduction were investigated.

Dannae racemosa was able to remove all of benzene and toluene concentrations from the air after 6 days. Hedera helix was able to reduce all of benzene and toluene concentration from the air after 6 and 5 days, respectively. The differences in Benzene and toluene remediation were assessed between the first and the third subsequent exposure and the results showed that the reduction rate increased for Dannae racemosa.

It can be concluded that the Dannae racemosa and Hedera helix could be used for benzene and toluene phytoremediation.

Zinc (Zn) is an essential micronutrient for higher plants that plays an important role in regulating the nitrogen metabolism, cell multiplication, protein synthesis, photosynthesis and auxin synthesis in plants and also a constituent of metalloenzyme or a cofactor for several enzymes but at high concentrations is toxic for plants. The present study investigates the anatomical and morphological parameters like shoot and petiole length, total leaf area and leaf numbers response of Capsicum annum L. under different concentrations (0 (control), 2.5, 5, 7.5, 10 and 15 mM) of zinc. Plants were grown in greenhouse under controlled conditions. Results indicated that increasing zinc concentrations caused significant decrease in stem and petiole length, leaf area and number of leaves (morphological parameters) compared to control plants (P ≤0.05). Also in anatomical studies we noticed several changes in cross section of leaf, stem and root. Certainly, zinc at high levels showed a negative effect on the overall growth of bell pepper plants.

C e s i u m i s v a s t l y o b s e r v e d i n n u c l e a r w a s t e w a t e r s a n d i s p o t e n t i a l l y c o n s i d e r e d a h a z a r d o u s m a t e r i a l, t h e r e f o r e, i t s r e m o v a l f r o m n u c l e a r s i t e w a s t e w a t e r s i s a n i m p o r t a n t t a s k. R e m o v a l o f r a d i o n u c l i d e s a n d h e a v y m e t a l s b y p h y t o r e m e d i a t i o n i s f a s t b e c o m i n g a t t r a c t i v e, d u e t o i t s h i g h e f f i c i e n c y a n d l o w c o s t. F u r t h e r m o r e, n a t i v e p l a n t s, i n t e r m s o f s u r v i v a l, g r o w t h a n d a l s o r e p r o d u c t i o n u n d e r e n v i r o n m e n t a l s t r e s s e s, h a v e m o r e s t a b i l i t y t h a n p l a n t s i n t r o d u c e d f r o m o t h e r e n v i r o n m e n t s. F o r p h y t o r e m e d i t i o n p u r p o s e s, i t i s e s s e n t i a l t o c h o o s e m e t a l t o l e r a n t a n d a c c u m u l a t o r p l a n t s p e c i e s t h a t a r e c a p a b l e o f c o n t a m i n a n t t r a n s p o r t a n d a c c u m u l a t i o n i n a r e l a t i v e l y s h o r t t r e a t m e n t t i m e. I n t h i s r e s e a r c h, t h e p o t e n t i a l o f C h e n o p o d i u m a l b u m f o r p h y t o r e m e d i a t i o n o f s o l u t i o n s c o n t a m i n a t e d w i t h c e s i u m w a s s t u d i e d. C h e n o p o d i u m a l b u m s e e d s w e r e g e r m i n a t e d i n s a n d, a n d t h e n o n e-m o n t h-o l d p l a n t l e t s w e r e t r a n s p l a n t e d i n p l a s t i c t r a y s c o n t a i n i n g n u t r i e n t s o l u t i o n s. H y d r o p o n i c a l l y g r o w n p l a n t s w e r e i n c u b a t e d i n d i f f e r e n t c o n c e n t r a t i o n s o f c e s i u m c h l o r i d e, r e p r e s e n t i n g 0.47, 1.58, 3.95 m g l$^{-1}$ o f c e s i u m i o n s i n t h e s o l u t i o n s, f o r a s e t p e r i o d. A t t h e e n d o f 14 d a y s, c e s i u m c o n c e n t r a t i o n s i n t h e s o l u t i o n s w e r e 0.15$p m$ 0.01, 0.95$p m$ 0.05 a n d 1.85$p m$ 0.29m g l$^{-1}$r e s p e c t i v e l y, m e a n i n g t h a t 68.08$p m$ 2.12%, 39.66$p m$ 3.4% a n d 52.99$p m$ 7.75% o f c e s i u m h a s b e e n r e m e d i a t e d f r o m t h e c o n t a m i n a t e d s o l u t i o n s. {i t C h e n o p o d i u m a l b u m} p l a n t s w e r e f o u n d t o b e e f f i c i e n t i n r e m e d i a t i n g c e s i u m i n a l l c o n c e n t r a t i o n s t e s t e d. P l a n t a n a l y s i s i n d i c a t e d t h a t 396.16$p m$ 6.33,521.4$p m$ 45.65 a n d 1256.66$p m$ 93.07 m g k g$^{-1}$ o f c e s i u m w e r e a c c u m u l a t e d i n p l a n t s a f t e r 14 d a y s. F u r t h e r m o r e, t h e u p t a k e a n d a c c u m u l a t i o n i n c r e a s e d w i t h i n c r e a s i n g m e t a l c o n c e n t r a t i o n s i n t h e s o l u t i o n s. A t l o w e s t c e s i u m c o n c e n t r a t i o n, p l a n t u p t a k e o f c e s i u m w a s f o u n d t o b e h i g h e r. F o r a n a t o m i c a l s t u d i e s a e r i a l o r g a n s o f p l a n t s, i n c l u d i n g t h e s t e m a n d l e a f, w e r e f i x e d, h a n d y s e c t i o n s w e r e p r e p a r e d a n d c o l o r e d a n d, c o n s e q u e n t l y, p h o t o g r a p h e d. A n a t o m i c a l s t u d i e s w e r e p e r f o r m e d i n m a n y p a r t s, i n c l u d i n g t h e p r i m a r y a n d s e c o n d a r y s t r u c t u r e o f t h e c o n t r o l p l a n t s, t h e s t r u c t u r e o f c o n t r o l l e a v e s a n d t h e a n a t o m i c a l s t r u c t u r e o f a e r i a l o r g a n s a f t e r t r e a t m e n t w i t h c e s i u m. M i c r o s c o p i c o b s e r v a t i o n o f a e r i a l o r g a n s i n d i c a t e d t h a t t h e t i s s u e s t r u c t u r e s o f t h e s e o r g a n s h a d n o t c h a n g e d. M o r e o v e r, i n c r e a s i n g c e s i u m c o n c e n t r a t i o n i n s o l u t i o n s c a u s e d a h i g h l e v e l o f c e s i u m a c c u m u l a t i o n i n s h o o t s, f o l l o w e d b y d e v e l o p m e n t i n x y l e m o r g a n s a n d c r y s t a l l i n e. C o o p e r a t i n g c e s i u m i n t h e c r y s t a l s t r u c t u r e a n d i t s a c c u m u l a t i o n i n v a c u o l e s p e r m i t t h e p l a n t t o u p t a k e m o r e r a d i o a c t i v e c e s i u m f r o m t h e e n v i r o n m e n t w i t h o u t a n y s e r i o u s l y i n c u r r e d d a m a g e t o t h e p l a n t. T h e s e c h a n g e s c o u l d b e a c c o u n t e d a s p l a n t r e s p o n s e s t o c e s i u m t o x i c i t y. I t i s c o n c l u d e d t h a t h y d r o p o n i c a l l y g r o w n {i t C h e n o p o d i u m a l b u m} c o u l d b e u s e d a s a p o t e n t i a l c a n d i d a t e p l a n t f o r p h y t o r e m e d i a t i o n o f s o l u t i o n s c o n t a m i n a t e d w i t h c e s i u m. M o r e o v e r, t h e p r e s e n t s t u d y o f f e r s a n e f f e c t i v e a n d h i g h l y e c o n o m i c a l m e a n s o f c o n t r o l l i n g r a d i o a c t i v e w a s t e w a t .