Different biological methods are gaining recognition for the production of silver nanoparticles (Ag-NPs) due to their multiple applications. One of the most important applications of Ag-NPs is their use as an anti-bacterial agent. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. In this study the biosynthesis of silver nanoparticles using Vitex negundo L. extract and its antimicrobial properties has been reported. The resulting silver particles are characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV–Visible (UV-Vis) spectroscopic techniques. The TEM study showed the formation of silver nanoparticles in the 10–30 nm range and average 18.2 nm in size. The XRD study showed that the particles are crystalline in nature, with a face centered cubic (fcc) structure. The silver nanoparticles showed the antimicrobial activity against Gram positive and Gram negative bacteria. Vitex negundo L. was found to display strong potential for the synthesis of silver nanoparticles as antimicrobial agents by rapid reduction of silver ions (Ag⁺ to Ag⁰).

Cytogenetic and molecular study was performed in 10 tetraploid cotton cultivars (Gossypium hirsutum L.) including parental genotypes and their F1 progenies. Cytogenetic study showed 2n = 4x = 56 in pa rental genotypes which differed significantly in their chiasma frequency and distribution as well as chromosome pairing indicating their genetic differences. Adjacent and alternate quadrivalents were formed in the cultivars studied which in turn bring about new genetic recombination and genetic linkages in the progenies. Out of 30 primers used 22 primers produced reproducible bands. In total 387 bands (loci) were obtained out of which 178 bands were polymorph and only 209 bands were common in cotton cultivars studied. Some of the cultivars showed presence of specific bands while, some bands were present in all except one genotype. Some bands were absent in the parental genotypes but present only in their hybrids, whereas some bands occurred in the parental genotypes but absent in their hybrid, all these indicate genetic diffrences of the cultivars studied which is also supported by clustering of the cultivars based on cytogenetic and RAPD data.

Banana (Musa spp.) is the world’s fourth most important food crop after rice, wheat and maize. The Valery banana cultivar is imported in Iran and well known as economic bananas in southern Iran. Shoots (with 2–3 cm stems) of the “Valery” cultivar of banana (Musa sp.) were selected, and meristematic tissue explants were isolated and cultured. Following embryo development, germination and differentiation, samples of regenerated plantlets were randomly taken and fixed in Formaldehyde, Glycial Acetic Acid, Alchol Ethylic (FAA) solution. Serial sections (10 μm) were prepared and stained in hematoxiline and eosine. An aqueous solution of 8-hydroxyquinoline was used to pre-treat the root tips. A solution of absolute ethanol and glacial acetic acid was used to fix the root tips. The mitotic cells identified with metaphase or prometaphase stages were used for chromosome counting. The meristematic tissue segments became swollen two weeks after cultures were initiated. Calli of the embryogenic line were kept separately; these tissues released embryogenic cells. The highest number of embryos (globular, torpedo and mature) were obtained with embryogenic medium (BM). The mature embryos and regenerated plantlets were cultured on regenerated medium (GM). The percentage of germination and development of completely regenerated banana plants was 90–96%. Histological study of regenerated shoots showed that there were many vascular tissues but of a small size; also that the vascular bundles were large and dispersed. The chromosomes were aggregated in metaphase. The regenerated plants from somatic embryos showed 60% triploidy, 10% diploidy and 30% aneuploidy and the chromosomes are more contracted and spread around the cell.

New advancements in tissue culture techniques have resulted in vitro propagation of several regenerations of horticultural crops. The somaclonal variation which occurs during plant tissue culture is a potential source for inducing new genetic variability in such crops. Several approaches have been utilized to ascertain the occurrence of somaclonal variation. The pomegranate plant can adapt to various environmental conditions and grow well in different kinds of soil and climate. Pomegranate Zagheh cultivar is mainly cultivated in the state of Esfehan, Kashan city in Iran. The present study was performed to investigate the potential occurrence of somaclonal variation in tissue culture regenerated plants of the cultivar Zagheh and provide morphological, cytological and molecular evidences for its occurrence. Nodal segments were chosen for the in vitro propagation of pomegranate. Explants were cultured on MS basal medium. We carried out both molecular (ISSR) and karyological studies in propagation collected. In the present study, we observed variation in both morphological (length of shoot, branch, internode, leaf and root and number of branch and root) and genetic features of the tissue culture regenerated plants. The regenerated plants of the third sub-culture differed from mother plants in the ISSR marker. We observed frequent occurrence of cells with different chromosome numbers, ranging from normal diploid 2n = 2x = 16 to tetraploid 2n = 32 chromosome number.

The experiment was carried out in a greenhouse, located in Tehran city, Iran. The objectives of this study was to evaluate the effects of fertilizer and acidic soil on the foliar and radicular growth of micropropagated plantlets of the pineapple cv. Merr (Ananas comosus L.). We evaluated the growth of that genotype in five different ages of acclimatizing: 1, 2, 3, 4, 5 and 6 months in greenhouse. The hardening of plantlets increased length of shoot, leaf length and leaf number and slip production, accelerated flowering and fruit maturity, caused uniform flowering and fruit ripening, and had no effect on sucker development. When hardening plantlets were at least 60 to 70 cm tall and 10 to 12 months old, an inflorescence bud was observed to form in the center of the leaves. Flowers (light red in color) opened row by row over a period of about two weeks. When fruits were about six months old, about four months after flowering has occurred, these changes were observed. The color of the shell changed from green to rich gold. When the fruit was golden half way up, it could be picked and eaten. The color change of the shell occurred first at the bottom of the fruit and moved upwards. During this change, the fruit became sweeter and the color of the flesh changed from white to yellow. Key words: Pineapple, Ananas comosus L., flowering, fruiting, growth.

Ziziphus jujuba (jujube) one of the well-known species of the ziziphus is medicinally important tree species that is also used as food source for its fruits. Conservation and breeding studies are in hand for this horticultural plant and for this reason a thorough population genetic study was performed. We carried out both molecular (Inter-retrotransposon amplified polymorphism: IRAP) and morphological (fruit characteristics) studies in 71 jujube trees collected randomly from 8 geographical regions in Iran. IRAP markers could differentiate the studied populations, as AMOVA revealed significant genetic difference among the studied populations. Networking and STRUCTURE analyses indicated that the jujube populations can be placed in two main genetic groups. Nm analysis revealed limited gene flow among populations. Jujube populations also differed significantly in their fruit characteristics and PCA analysis showed that these populations are diverged in these characters too. Data obtained can be used in future conservation and breeding studies of this important horticultural plant.