Pre-Germination Treatments at Operational Scale for Six Tree Species from the Sclerophyll Forest of Central Chile.

Eduardo Cartes-Rodríguez,Marta González-Ortega,Manuel Acevedo,Pedro León-Lobos,Carolina Álvarez-Maldini,Alejandro Urbina-Parra

doi:10.3390/plants11050608

Abstract

Sclerophyll forest in Mediterranean central Chile has been subjected to severe degradation due to anthropic disturbances and climate change and is in need of restoration. Since direct seeding is usually unsuccessful, we need to research seed propagation to produce plants for restoration. Our objective was to assess pre-germination treatments for six native woody species (Acacia caven, Lithraea caustica, Quillaja Saponaria, Porlieria chilensis, Kageneckia angustifolia, and Ceratonia chilensis) of the sclerophyll forest, considering its operational applicability and consequences for nursery plant production. Treatments were selected according to previous studies, and operational applicability in nurseries. Germination and level of seeds water imbibition were assessed. Results indicate that time for seed water imbibition is critical for germination in A. caven, P. chilensis and K. angustifolia, with an average germination of 90.2 ± 2.0%, 85.0 ± 4.7%, and 47.4 ± 2.3%, respectively. Gibberellin did not improve germination compared to water soaking in Q. Saponaria, K. angustifolia and P. chilensis. In addition, physical scarification is a suitable treatment for L. caustica and C. chilensis, instead of chemical scarification, avoiding handling toxic and corrosive compounds in nurseries. We recommend assessing seed water imbibition rates as a key factor for proper germination processes.

Highlights

There are five Mediterranean-type climate regions in the world that represent less than 5% of global surface but and are catalogued as biodiversity hotspots because they harbor 20% of endemic vascular plants of the planet [1,2]
From the estimation of the number of seeds per kilogram, it is observed that bigger seeds belong to A. caven with 7,554 ± 216 seeds kg−1, followed by L. caustica and C. chilensis with 23,066 ± 660 seeds kg−1 and 24,359 ± 543 seeds kg−1, respectively, and P. chilensis with 37,169 ± 2379 seeds kg−1 and Q. saponaria with 112,413 ± 1,396 seeds kg−1; seeds with the lower weight were observed in K. angustifolia with 136,935 ± 3855 seeds kg−1
After soaking in water for 24 h, significant increase was observed in this variable in all evaluated species, while only for A. caven, P. chilensis and K. angustifolia a significant increase in moisture content was observed after 48 h of soaking (Table 1)

Summary

Introduction

There are five Mediterranean-type climate regions in the world that represent less than 5% of global surface but and are catalogued as biodiversity hotspots because they harbor 20% of endemic vascular plants of the planet [1,2] These regions are characterized by higher levels of endemism of the vascular flora, which are adapted to seasonal water deficit and high summer temperatures [3]. The Mediterranean-type climate region of Chile has been subjected to strong anthropic pressures [6] due to changes in soil use, which has reduced the coverage, structure, and composition of this ecosystem, and this has been worsened by the effect of forest and soil degradation and bushfires [7,8,9,10] These events have increased in severity during the last decade, as Chile has been facing a mega-drought since 2010 [11,12,13]. This is even more relevant for sclerophyll forests because it requires greater restoration efforts considering its actual degradation state [18]

Objectives

Methods

Results

Discussion

Conclusion