Influence of Temperature on Seed Germination of Five Wild-Growing Tulipa Species of Greece Associated with Their Ecological Profiles: Implications for Conservation and Cultivation

Abstract

Although tulips are famous worldwide as ornamental plants, the knowledge about the seed germination of wild-growing species remains limited. The aim of the present study was to investigate the effect of temperature on seed germination of the local, wild-growing Greek endemics Tulipa bakeri and T. goulimyi and the sub-Balkan endemic T. undulatifolia, which are threatened with extinction, as well as the Mediterranean T. australis and the Asiatic T. clusiana naturalized on Chios Island (Greece). The germination responses at five constant temperatures (5, 10, 15, 20, and 25 °C) were assessed for all studied species in growth chambers under a 12:12 light–dark photoperiod. The ecological profile for each species was developed in R using open-source bioclimatic data; this was built to illustrate the abiotic environmental conditions of their wild habitats, to facilitate the examination of temperature effects on seed germination, and to facilitate their cultivation in artificial environments. The results indicated that the seed germination requirements of the studied species had a range-specific temperature dependence, reflecting their natural adaptation to local ecological conditions. Seed germination of T. bakeri, T. australis, and T. clusiana was observed only in a narrow range of very low temperatures (5–10 °C), whereas germination of T. undulatifolia and T. goulimyi occurred at temperatures between 5 and 15 °C. A temperature increase to 20 or 25 °C resulted in the absence of seed germination for all five Greek tulip species. The germinated seeds were planted in pots and bulblets were developed under greenhouse conditions. Seeds and bulblets constitute valuable genetic materials for the cultivation and ex situ conservation of these five Greek tulip species, three of which are threatened with extinction.

Adaptability of Wild-Growing Tulips of Greece: Uncovering Relationships between Soil Properties, Rhizosphere Fungal Morphotypes and Nutrient Content Profiles

“…All the data furnished herein can be further exploited in attempts to cultivate ex situ in a sustainable way the diversity of the wild-growing Greek tulip species ( n = 15) and finally domesticate them in artificial settings. Facilitating the latter is a complex and multi-dimensional process given that each of these wild-growing tulips originates from different environmental conditions, has different ecological preferences and has developed different natural adaptations [ 1 , 55 ]. To this end, the data generated herein can be used in the future to formulate species-specific fertilization guidelines to be followed in artificial settings which may benefit to a large extent from the insight into the species-specific nutritional needs, elemental uptake potential, and transport as detected in the original wild habitats of the wild-growing Greek tulips studied herein.…”

Effect of Temperature on Breaking of Morphophysiological Dormancy and Seed Germination Leading to Bulblet Production in Two Endemic Tulip Species from Greece

“…Botanical tulips are almost equally famous ornamental plants [1], and Greek botanical tulips among them are associated with a documented global electronic commerce over the internet involving many nurseries in different European countries [2]. To date, wild phytogenetic resources of tulips have gained research interest leading to domestication efforts for different species with the aim to effectively reproduce and cultivate them in artificial environments; such examples have employed to date several Chinese [3][4][5] and Greek [2,6,7] wild-growing tulips. The focus of research efforts toward this direction to date is due to the interesting ornamental characteristics and the unique identity of certain species of botanical tulips, and their strong natural adaptability (even to cultivation settings) coupled with enhanced resilience to pathogens.…”

“…The focus of research efforts toward this direction to date is due to the interesting ornamental characteristics and the unique identity of certain species of botanical tulips, and their strong natural adaptability (even to cultivation settings) coupled with enhanced resilience to pathogens. These assets may trigger-independently or in combination-horticultural and consumer interest, and therefore, botanical tulips can be engaged in coordinated breeding programs aiming to develop new tulip cultivars through exploitation of interesting phytogenetic resources of wild provenance [2,[4][5][6].…”

“…Among 15 members of the genus Tulipa present in Greece either in mainland and/or insular regions [2,6,8], Tulipa hageri Heldr. and T. orphanidea Heldr.…”

“…The asexual multiplication of tulip bulbs has been efficiently described in various literature sources (e.g., [10][11][12][13][14]). However, the knowledge about the requirements for seed germination of wild-growing tulip species still remains limited [5,6]. Proliferationwise, sexual propagation is considered the commonest and most cost-efficient propagation method used in nurseries [15] and is associated with enhanced genetic diversity due to sexual reproduction.…”