Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Marta Vargas,Claudio Inostroza-Blancheteau,Elda Jofré,Carlos Navarrete,Jaime Bravo,Fabiola Jamett,Cristian Ibáñez

doi:10.1186/s40693-018-0075-8

Marta Vargas, Claudio Inostroza-Blancheteau + Show 5 more

Open Access

https://doi.org/10.1186/s40693-018-0075-8

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Abstract

Background“Garra de Leon” (Leontochir ovallei) is an ephemeral endangered Alstroemeriaceae species endemic to Chile. Despite many efforts to improve the conservation of this species, the stimulation of dormant seeds and the production of rhizomes under controlled conditions remain unexplored. The aims of this study were to examine the germination responses of L. ovallei seeds under different in vitro conditions and to evaluate the formation of viable rhizomes after transplantation from in vitro to ex vitro conditions.MethodsWe evaluated five in vitro seed germination treatments: (1) acid scarification, (2) acid scarification followed by imbibition of seeds in aerated water, (3) imbibition of seeds in gibberellic acid, (4) clipping of seeds with a scalpel, and (5) seeds without any treatment (control). Seedlings obtained under in vitro conditions were transplanted to ex vitro conditions following a gradual acclimation process. After eight months, the number of rhizomes per plant was counted. To test asexual multiplication, each rhizome with its respective storage organ was divided using a scalpel and then left to rest for two years before subsequent evaluation of viability. After that period, the rhizomes were re-hydrated, and the emergence of plants after three months was evaluated.ResultsSeeds exposed to treatment 2 showed the highest germination percentage (36%), followed by the seeds whose coats were clipped (14%) and seeds treated with sulphuric acid (8%). The seed germination of the control treatment was 3%. After transplantation to ex vitro conditions, we obtained 220 rhizomes, with an average of three to six rhizomes per plant. After two years of dormancy, a total of 34 rhizomes (of 220 rhizomes) reactivated growth after re-ydration, indicating that, at least, 15,5% responded positively to watering.ConclusionsWe found that the seed germination of L. ovallei was increased by strong acidic conditions, suggesting that the main type of seed dormancy in this species is physical. However, germination was further increased by aeration, indicating embryo dormancy. In addition, we were able to obtain viable rhizomes by transplanting seedlings from in vitro to ex vitro conditions, which may be helpful for the propagation and ex situ conservation of this rare geophyte of Chile and potentially other geophyte species adapted to wet-dry cycle environments.

Highlights

Geophytes are a dominant component of arid plant communities
The O.R. for germination observed for the seeds treated with treatment #4 was 5.3 (2.9; 9.0) higher, whereas O.R. of 2. 8 (1.3; 5.48) and 1.3 (0.4; 3.2) were observed for the seeds subjected to treatment #1 and treatment #3, respectively (Table 1)
Previous studies of Chilean geophytes growing from semiarid to Mediterranean areas and from the Pacific coast to the Andes mountain limits of their distribution have reported that seed germination in several species of Alstroemeriaceae (e.g., Alstroemeria pseudospathulata and Bomarea salsilla) is stimulated by treatments similar to those used in this study, indicating the effectiveness of these treatments for breaking physical and chemical dormancy [36,37,38,39,40,41,42], in contrast to the results for L. ovallei

Summary

Introduction

Geophytes are a dominant component of arid plant communities. Their survival in these water-limited environments depends on two important aspects. These buds re-sprout, and photosynthesis activates the replenishment of storage reserves to enable new life cycles [1, 2] This aspect ensures that plant communities will persist and continuously colonize the environment. Geophytes (like many other plants) must maintain reproduction based on seeds to ensure genetic variability and gene flow between and among populations [3]. This strategy is pivotal for plants to expand their area of distribution and, more importantly, to transmit to the generation information on how to survive in harsh environments. Studies of the propagation of non-domesticated geophytes remain scarce

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