Juniperus seravschanica is the southernmost population of Juniperus that has a limited habitat in the world near the equator. In Iran, the lone habitat of this species in the Genow mountains has been endangered with thin foliage, abscissing needles, and dried shoots. The current study investigated the effects of climatic, genetic factors, and physiologic indices on the distribution of J. seravschanica. Distribution was evaluated for 450 ha and physiological indices were evaluated for two groups: (A) trees with dried branches and (B) trees without dried branches. Results showed that the distribution of J. seravschanica in the Genow habitat was influenced by elevation, slope degree, aspect, and distance to stream. Results also indicated that max temperature and precipitation are two effective factors that have the highest effects on falling needles and drying branches of J. seravschanica. Chlorophyll, relative water content (RWC), and relative turgidity (RT) are significantly influenced by max temperature. Endangered trees with dried branches had a lower chlorophyll content, RWC, and RT than trees without dried branches. Vulnerability of J. seravschanica was significantly influenced by its genetic structure. Results of AMOVA showed 83% genetic variability between two groups of J. seravschanica trees.

A water deficit can significantly limit the sustainable production of plants, resulting in reduced growth, development, and flowering. The use of biostimulants improves plant stability and promotes growth under low-irrigation conditions. This study evaluated the effects of biostimulators on the growth, development, and flowering of tuberose (Polianthes tuberosa L.) under water-deficit conditions. This experiment was conducted using a completely randomized design with three replications in pots and eight treatments: four irrigation regimes (100%, 80%, 60%, and 40%), and four biostimulant treatments (foliar application of seaweed extract (SE) at concentrations of 500, 1000, and 2000 ppm; humic acid (HA) application at concentrations of 150, 300, and 600 ppm; inoculation of the bed with mycorrhiza; a control treatment without biostimulators). We measured the length, diameter, and fresh and dry weight of the flower pedicel; the number of leaves per plant; the fresh and dry weight of the leaves, stem, and root of each plant; and the content of photosynthetic pigments, phenol, proline, carbohydrates, and flavonoids. The results of this study showed that the growth and development of tuberoses were positively affected by different irrigation levels and biostimulants. The highest morphological characteristics were observed in plants irrigated at 100% field capacity. In contrast, the irrigation regime treatment of 40% of the field capacity combined with 600 mg/l of HA had the most detrimental effect on plant growth indicators. Findings suggest that application of 2000 ppm of SE biostimulant contributes to the mitigation of the negative effects of water deficit in tuberose production under greenhouse conditions as an irrigation water conservation strategy that can be exploited to maintain high yields.

Dog rose (Rosa canina L.) is a medicinal-ornamental shrub that has a natural habitat in some regions of Iran. Climatic and geographical conditions of the habitat are the most important factors that have affected the distribution and habitat suitability of this species. Recognizing the factors affecting the habitat suitability of plants is ...

Water deficit can significantly limit the sustainable production of plants, resulting in reduced growth, development, and flowering. Previous studies have shown that the use of biostimulants improves plant stability and promotes growth under low irrigation conditions. The study aims to evaluate the effects of biostimulators on the growth, development and flowering of tuberose (Polianthes tuberosa L.) under water deficit conditions. The experiment was conducted using a completely randomized design with three replications in pots and eight treatments: four irrigation regimes (100%, 80%, 60%, and 40%), and four biostimulant treatments (foliar application of seaweed extract at concentrations of 500, 1000, and 2000 ppm, humic acid at concentrations of 150, 300, and 600 ppm, inoculation of the bed with mycorrhiza, and a control treatment without biostimulators). The length, diameter, fresh and dry weight of the flower pedicel, the number of leaves per plant, the fresh and dry weight of the leaves, stem and root of each plant, as well as the content of photosynthetic pigments, phenol, proline, carbohydrates and flavonoids were measured. The results of this study showed that the growth and development of tuberoses were positively affected by different irrigation levels and biostimulants. The highest morphological characteristics were observed in plants irrigated at 100% field capacity. In contrast, the irrigation regime treatment of 40% of the field capacity combined with 600 mg/liter of humic acid had the most detrimental effect on plant growth indicators. Under stress conditions, the plant also exhibited increased levels of proline, carbohydrates, and flavonoids, which are commonly used as indicators of stress tolerance.