مجله گل و گیاهان زینتی
سال سوم شماره 2 (پاییز و زمستان 1397)

Undoubtedly cut rose is one of the most economically and favorite ornamental plants in the world. Management of rose architecture plays an important role on the year-round flower production as it greatly determines plant life span, and effects both plant development and the quality of the flowering shoots (length, diameter and weight). Traditional cut-flower rose production involves growing plants in the ground and training the canopy vertically as a tall hedge. However, nowadays rose growers have changed this method by bending the non-productive shoots (stems with low length and diameter and also with blind shoot potential). Bending of shoots results in reduced indigenous IAA hormone and increased cytokinin and ethylene levels which in turn lead to a decline in the growth and an increase in branching and increase in flowering. Shoot bending increase the light capture and it makes more photosynthetic assimilates. Moreover, it changes the translocation of photosynthetic assimilates from the foliage of bended shoots towards the bottom breaks, thus, it increases the growth and flower quality. Bending also increases light absorption and production of photosynthetic assimilates and their translocation from the foliage of the bended shoots towards the bottom breaks. This could increase growth rate and improve the quality of the flowers. In the present research, the management of the cut rose plant structure with an emphasis on shoot bending, has been thoroughly reviewed.

This experiment was performed to evaluate the effect of different nitrogen forms (ammonium to nitrate ratio) on the growth and flowering characteristics of two gerbera cultivars (‘Stanza’ and ‘Double Dutch’). The aim was to recommend the appropriate amount of NH4+:NO3¯ ratio in the nutrient solution to optimize quantity and quality characteristics in gerbera. This experiment was conducted in a completely randomized factorial design with two factors including NH4+:NO3¯ ratios and cultivar type with three replications. The NH4+:NO3¯ ratios (0:100, 20:80, 40:60, and 60:40) were supplied as a first factor and second factor was gerbera cultivars (‘Stanza’ and ‘Double Dutch’). The results indicated that increasing ammonium concentration in the nutrient solution to more than 40% of total N, significantly reduced growth indices and gerbera flower numbers compared to NH4+:NO3¯ ratio of 20 to 80. Results showed that the highest flower number (314 flowers m-2 year-1), stalk dry weight (5.2 g), flower stalk diameter (0.92 cm), flower stalk weight (2.31 Kg) and vase life (14 days) were obtained in 80:20 of NH4+:NO3¯ ratio. Thereofre, nutrient solution with NH4+:NO3¯ ratio of 20:80 is an appropriate solution recommended for commercial production of gerbera cut flowers in order to achieve the optimum quantity and quality yield of Cut Gerbera.

Palm Family (Arecaceae-Palmaceae) is of great importance in tropical and subtropical regions of the world and includes about 184 genera and between 2000-2500 species. Ornamental palms are one of the most important elements of landscapes in tropical and subtropical regions due to their growth habit, forms, color and also their considerable adaptability to climatic and soil conditions. Some rare species are also found in the landscapes of warm temperate, transitional zones and even temperate climates due to their adaptation to low temperature. Ornamental palms are used for mass plantation in groves or groups, for rows, lines or avenues and also as focal points. Palms are used as landscape features for public buildings, parks, streets, swimming pools, restaurants, hotels, recreation centers particularly in coastal zones. Palms are usually low maintenance landscape plants and very suitable candidates for xeriscaping particularly in tropical and subtropical regions with limited water resources. Low temperature is one of the main limiting factors for cultivation of ornamental palms in landscapes especially in transitional, warm temperate and temperate climates that lead to chilling and freezing injury. In this review, some important features of ornamental palms for landscape utilization and some prevailing challenges are addressed. Meanwhile, some plam species which are suitable for cooler areas are listed.

Lisianthus (Eustoma grandiflorum (Raf.) shinn.) is one of the most important cut flowers in the world. However, a relatively short vase life reduces its marketability. Usually Tragacanth gel and hot water treatment is applied in fruits and there are a few reports in cut flowers too. The aim of the present study was to evaluate the effects of tragacanth gel and hot water treatments in extending vase life and increasing the qualitative properties of cut flowers of lisianthus. For this purpose an experiment was conducted based on completely randomized design with thirteen treatments including three levels of tragacanth (1, 2.5 and 5%) in two ways (pulsing and continues), hot water in 35 and 45 °C for 2, 5 and 10 min and control with three replications,. The highest vase life, flower weight and the lowest bacteria population were obtained in 2.5 % tragacanth pulse treatment. Maximum catalase and peroxidase activity was obtained in 1% continues tragacanth treatment. The highest relative water content of leaves and petals was observed in hot water in 35 °C for 2 min and 2.5 and 5% continues tragacanth treatment, respectively. The highest ion leakage was observed in 2.5 and 5% continues tragacanth treatment. The lowest ion leakage was obtained in hot water in 45 °C for 2 min. Generally, both tragacanth and hot water treatments were effective on extending vase life and improving quality properties of lisianthus, but tragacanth pulse treatment showed the best effects.

Flower Paper (Bougainvillea spectabilis Willd) is one of the most important flowers in the tropical region. In this study, effect of different cutting time (June, July, August and September) on different vegetative characteristics of red flower was evaluated. The experiment was conducted in a completely randomized design with four replications. According to the results, the highest fresh and dry weight of root, root length was observed in June. Other traits such as number of leaves, number of shoots, shoot length, fresh and dry weight of shoots and root length significantly increased in cuttings taken in July compared to other months. It can be concluded that July is the best time to cutting red flowers in tropical conditions.

This research was carried out with the aim of introducing, identifying and evaluating the morphology and phenology of species present in the Iranian National Botanical Garden. Initially, the display area of 1.8 hectares was divided into six pieces. Their planting plan was prepared and species were identified. Then, phenological changes were reviewed over 20 years. The results showed that 63 tree species, 87 species of shrubs, 31 species of grasses and 14 species of plantation, overally 195 species and cultivars of 100 genera and 45 families, were located in the experimental plot and adapted to the climate of Tehran. Then, the phenological changes and their uses in forest or green space were studied to determine six groupssuch as: most longitudinal and diagonal growth per year (16 species), relatively stable (12 species), evergreen (33 species), species with changes in leaf color (6 species), long flowering period (10 species), and autumn or winter flowering (5 species).

Plant species with more than two sets of chromosome are called polyploids, which are usually spontaneously created by a mutation during the evolution process. The increased genetic diversity in polyploid plants is considered to be an important strategy in adapting them to new environments which are revolutionizing with time. The changes that are usually associated with auto and allopolyploids include alteration of cell size and morphological or physiological modifications. The aim of this study was to review some aspects of polyploidization and its impact on breeding of ornamental plants. Furthermore, the advantages and disadvantages of the polyploid plants, chromosome doubling agents and application of polyploidization in ornamental plants are reviewed and polyploidization as a modern breeding method is discussed. This review suggested that although there are some disadvantages with polyploid plants, however, they have major advantages over non-polyploids. In using chromosome doubling agents, results indicated that due to complexity of the mode of action of these agents and response of different plants to them, type and concentration of polyploid inducing agents, exposure period and explant type are to be optimized. Moreover, the results suggested that polyploidization induce changes in plant's vigor, size of the fruits and flowers, size and thickness of the leaves, fertility and resistance to biotic and abiotic stresses and therefore it is considered as a modern breeding method for ornamental plants.