Carrera de Biología, Universidad Mayor de San Andrés, La Paz, Bolivia.
Instituto Experimental de Biología "Dr. Luis Adam Briançon", Universidad Mayor, Real y Pontificia de San Francisco Xavier de Chuquisaca, Sucre, Bolivia.
PLoS One. 2021 Mar 31;16(3):e0248619. doi: 10.1371/journal.pone.0248619. eCollection 2021.
Germination and seedling establishment are two critical processes in the life cycle of plants. Seeds and seedlings must pass through a series of abiotic and biotic filters in order to recruit as members of their communities. These processes are part of the regeneration niche of the species. In arid regions, the regeneration niche is frequently associated to facilitation by shade. Facilitation is a positive interaction between plants, in which one of them acts as a benefactor (the nurse) of the other (the beneficiary). The result of this interaction can be reflected in the increased growth, survival, and/or reproduction of the beneficiary plant. In this study, we determined experimentally the effect of shade and irrigation on the germination and early survival of dominant species of a semi-arid Andean region, the Bolivian Prepuna. An experiment with Acacia feddeana, Prosopis ferox, Cercidium andicola (woody species), Parodia maassii, and Oreocereus celsianus (cactus species) was carried out at an experimental garden in La Paz, Bolivia, with a bifactorial design, considering shaded and unshaded pots, subjected to two irrigation treatments (≈50 and 80 mm of rainfall during the whole study period). Microenvironmental conditions did not affect the seed germination of the woody species. However, they showed differences in seedling survival: A. feddeana survived better under shade, whereas P. ferox and C. andicola survived better without shade. Cercidium andicola, compared to P. ferox, was more affected by shade and low irrigation. Although germination success of cacti was low, both species germinated better under shade and with high irrigation. These results showed differences in the regeneration niche of dominant species of the Prepuna which may favor their coexistence and which may be characteristic of other dry Andean regions.
萌发和幼苗建立是植物生命周期中的两个关键过程。种子和幼苗必须通过一系列非生物和生物过滤器才能成为其群落的成员。这些过程是物种再生生态位的一部分。在干旱地区，再生生态位通常与遮荫促进有关。促进是植物之间的一种积极相互作用，其中一种植物充当另一种植物（受益植物）的保护者。这种相互作用的结果可以反映在受益植物的生长、存活和/或繁殖的增加上。在这项研究中，我们通过实验确定了遮荫和灌溉对玻利维亚半干旱 Prepuna 地区优势物种萌发和早期存活的影响。在玻利维亚拉巴斯的一个实验花园中，进行了一项涉及 Acacia feddeana、Prosopis ferox、Cercidium andicola（木本物种）、Parodia maassii 和 Oreocereus celsianus（仙人掌物种）的实验，采用双因素设计，考虑了遮荫和非遮荫盆，进行了两种灌溉处理（≈50 和 80 mm 的降雨量在整个研究期间）。微环境条件并不影响木本物种的种子萌发。然而，它们在幼苗存活方面表现出差异：A. feddeana 在遮荫下存活得更好，而 P. ferox 和 C. andicola 在没有遮荫的情况下存活得更好。与 P. ferox 相比，C. andicola 更容易受到遮荫和低灌溉的影响。尽管仙人掌的萌发成功率较低，但两种仙人掌在遮荫和高灌溉下的萌发效果更好。这些结果表明，Prepuna 的优势物种的再生生态位存在差异，这可能有利于它们的共存，并且可能是其他干燥的安第斯地区的特征。
