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Zahra Heidari Sureshjani, Ghasem Karimzadeh, Sajad Rashidi Monfared,
Volume 9, Issue 1 ((Spring and Summer) 2022)
Abstract

Extended Abstract
Introduction: St. John’s wort is one of the most amazing and medicinal plants of interest worldwide, which is nowadays known as a certain cure for depression. However, the presence of dormancy and low seed germination is a barrier to the progress of its breeding programs. Despite the richness of the plant’s genetic resources, there are only a few studies reported on its propagation and maintenance in Iran, most of which do not mention the geographical origin of the used seeds or explants. The current study was carried out aiming to evaluate in vitro plant propagation of eight Iranian endemic populations of St. John’s wort seeds which belonged to different geographical origins, emphasizing seed dormancy phenomena.
Materials and Methods: Following the collection of eight populations of St. John’s wort (Hypericum perforatum L.) seeds from different geographical regions of Iran, the Murashige and Skoog culture media (common salt mixture as a control, MS improved with gibberellic acid and a modified combination of MS) was used in an effort to investigate the effect of culture medium as well as seed collection locations on the germination percentage of these populations.
Results: The results showed that the interaction between the seed collection locations and the culture medium on seed germination was significant at P<0.01. Besides, the effect of changing culture media on seed germination was significant in all populations at P<0.01, except for Meshkin-Shahr. In other words, the seeds collected from Meshkin-Shahr germinated easily as well as notably under in vitro conditions (97.3% on average), and there was no need either to modify the combination of MS medium or to use gibberellic acid for seed dormancy elimination. The seeds originated from Challus and Peresk had the lowest germination in the control medium (22.3%, on average). Seeds from Challus and Saqqez had better germination in the media enriched with gibberellic acid compared to the control and the modified MS media (88% and 65%, respectively). However, less than half of the Parvar seeds germinated in the MS medium improved with GA3, compared to the control. Cultivation of seeds obtained from Fereydunkenar in common MS medium also led to better germination than using GA3 and modifying the combination of medium with 95% and 99% confidence levels, respectively.
Conclusion: The results of the current study demonstrated that the observed difference in seed germination percentage is remarkable in the Iranian endemic St. John’s wort populations under in vitro conditions. Moreover, the variation among national populations was significant. Besides, the response of the seed populations originating from different locations varied with respect to the changes in the culture medium and in the different cases. This shows the considerable effect of the growth location of the maternal plant on the characteristics of the next generation seeds, especially the way they germinate. Hence, it is very important to pay attention to the seed’s origins in the studies and it is investigable.

Highlights:
  1. This is the first report on the in vitro seed dormancy elimination in the eight Iranian St. John’s wort populations.
  2. It was for the first time bringing up the geographical origins of seeds in the national germination studies on the St. John’s wort.
  3. It is a quite new method to use a modified combination of MS medium for seed dormancy elimination in the St. John’s wort.

Iraj Rahimi, Ismail Asadi, Pejman Tahmasebi, Alireza Monfared, Ali Abbasi Suraki,
Volume 9, Issue 2 ((Autumn & Winter) 2023)
Abstract

Extended Abstract:
Introduction: Predation is the common fate of most seeds produced by plants. Loss of seeds due to predation can be harmful to plants and causes such species to become rare, as rare species are vulnerable to extinction through processes that disrupt the mechanisms of plant dispersal. Therefore, the purpose of this study was to investigate the effects of pre-dispersal seed predation on rare astragalus species and their common counterparts.
Materials and Methods: In order to investigate the effects of pre-dispersal seed predation, 12 species including 6 species with herbaceous life form (including three rare species (A. Caraganae, A. Heterophyllus and A. Holopsilus) and three common species (A. Angustiflorus, A. Curvirostris and A. Effusus) and 6 species with shrub life form (including three rare species (A. Cephalanthus, A. Camphylanthus and A. Cemerinus) and three common species (A. Verus, A. Susianus and A. Rhodosemius) were compared in 2018 and 2019. From each plant type, 20 and from each plant type 10 pods (for each plant type 200 pods), randomly selected and the parameters of area size, perimeter length, length, width, length-to-width ratio, circularity, and distance between IS and CG from the seed center were measured and compared for both pods and seeds of these species. Also, pod mass and seed mass, number of pods and seeds attacked by predators, number of healthy seeds, pod shape and seed shape of species were compared.
Results: The results of comparing the mean morphological characteristics of seeds between herbaceous and shrub astragalus species showed the highest and lowest area size, perimeter length, length, width, length-to-width ratio, circularity, and distance between IS and CG from the seed center, was related to common astragalus species. in the case of shrub species, most of the characteristics were related to common astragalus species, and the lowest characteristics were related to rare astragalus species. The results of morphological characteristics of pods between herbaceous and shrub species showed that the highest and lowest characteristics belonged to both groups of common and rare species. The results showed that the highest and lowest means of seed mass, number of damaged seeds, number of healthy seeds, and seed shape under the influence of pre-dispersal seed predation among herbaceous species showed that the highest and lowest means of seed mass, number of damaged seeds, belonged to common species. the highest and lowest numbers of healthy seeds and seed shapes belonged to rare species. Among the shrub astragalus species, the highest seed mass, the number of damaged seeds, the number of healthy seeds, and the seed shape were related to common astragalus species, and the lowest of these characteristics were related to rare astragalus species.
Conclusion: The overall results showed that the more species that can produce seeds of larger and smaller sizes, the better the distribution status. And the larger the seed and pod mass of the plant and the larger the shape, the more predators attack those species, but the amount of predator attacks does not lead to the rarity of the species.

Highlights:
  1. The role of pre-dispersal seed predation on rare and common astragalus species was investigated.
  2. Morphological characteristics of seeds and life forms of rare and common astragalus species were compared.


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