Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus
The epiphytic growth habit in many Ficus species during their juvenile stages has commonly been hypothesized to be an adaptation for avoiding deep shade in the forest understory, but this has never been tested experimentally. We examined growth and ecophysiology in seedlings of three hemiepiphytic (...
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2013
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00319317_v148_n1_p74_Hao http://hdl.handle.net/20.500.12110/paper_00319317_v148_n1_p74_Hao |
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paper:paper_00319317_v148_n1_p74_Hao2023-06-08T14:58:59Z Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus Goldstein, Guillermo Hernan water adaptation article biomass drought Ficus photosynthesis physiology radiation exposure seedling sunlight xylem Adaptation, Biological Biomass Droughts Ficus Photosynthesis Seedling Sunlight Water Xylem The epiphytic growth habit in many Ficus species during their juvenile stages has commonly been hypothesized to be an adaptation for avoiding deep shade in the forest understory, but this has never been tested experimentally. We examined growth and ecophysiology in seedlings of three hemiepiphytic (Hs) and three non-hemiepiphytic (NHs) Ficus species grown under different irradiance levels. Both Hs and NHs exhibited characteristics of high light requiring species, such as high plasticity to growth irradiance and relatively high maximum photosynthetic assimilation rates. Diurnal measurements of leaf gas exchange showed that Hs have much shorter active photosynthetic periods than NHs; moreover, leaves of Hs have lower xylem hydraulic conductivity but stronger drought tolerance as indicated by much lower rates of leaf diebacks during the drought treatment. Seedlings of NHs had 3.3- and 13.3-fold greater height and biomass than those of Hs species after growing in the nursery for 5months, indicating a trade-off between growth and drought tolerance due to the conflicting requirements for xylem conductivity and cavitation resistance. This study does not support the shade-avoidance hypothesis; rather, it suggests that the canopy regeneration in Hs is an adaptation to avoid alternative terrestrial growth-related risks imposed to tiny Ficus seedlings. The NHs with terrestrial regeneration reduce these risks by having an initial burst of growth to rapidly gain relatively large seedling sizes, while in Hs seedlings more conservative water use and greater drought tolerance for surviving the canopy environment are intrinsically associated with slow growth. © Physiologia Plantarum 2012. Fil:Goldstein, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00319317_v148_n1_p74_Hao http://hdl.handle.net/20.500.12110/paper_00319317_v148_n1_p74_Hao |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
water adaptation article biomass drought Ficus photosynthesis physiology radiation exposure seedling sunlight xylem Adaptation, Biological Biomass Droughts Ficus Photosynthesis Seedling Sunlight Water Xylem |
| spellingShingle |
water adaptation article biomass drought Ficus photosynthesis physiology radiation exposure seedling sunlight xylem Adaptation, Biological Biomass Droughts Ficus Photosynthesis Seedling Sunlight Water Xylem Goldstein, Guillermo Hernan Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| topic_facet |
water adaptation article biomass drought Ficus photosynthesis physiology radiation exposure seedling sunlight xylem Adaptation, Biological Biomass Droughts Ficus Photosynthesis Seedling Sunlight Water Xylem |
| description |
The epiphytic growth habit in many Ficus species during their juvenile stages has commonly been hypothesized to be an adaptation for avoiding deep shade in the forest understory, but this has never been tested experimentally. We examined growth and ecophysiology in seedlings of three hemiepiphytic (Hs) and three non-hemiepiphytic (NHs) Ficus species grown under different irradiance levels. Both Hs and NHs exhibited characteristics of high light requiring species, such as high plasticity to growth irradiance and relatively high maximum photosynthetic assimilation rates. Diurnal measurements of leaf gas exchange showed that Hs have much shorter active photosynthetic periods than NHs; moreover, leaves of Hs have lower xylem hydraulic conductivity but stronger drought tolerance as indicated by much lower rates of leaf diebacks during the drought treatment. Seedlings of NHs had 3.3- and 13.3-fold greater height and biomass than those of Hs species after growing in the nursery for 5months, indicating a trade-off between growth and drought tolerance due to the conflicting requirements for xylem conductivity and cavitation resistance. This study does not support the shade-avoidance hypothesis; rather, it suggests that the canopy regeneration in Hs is an adaptation to avoid alternative terrestrial growth-related risks imposed to tiny Ficus seedlings. The NHs with terrestrial regeneration reduce these risks by having an initial burst of growth to rapidly gain relatively large seedling sizes, while in Hs seedlings more conservative water use and greater drought tolerance for surviving the canopy environment are intrinsically associated with slow growth. © Physiologia Plantarum 2012. |
| author |
Goldstein, Guillermo Hernan |
| author_facet |
Goldstein, Guillermo Hernan |
| author_sort |
Goldstein, Guillermo Hernan |
| title |
Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| title_short |
Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| title_full |
Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| title_fullStr |
Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| title_full_unstemmed |
Is hemiepiphytism an adaptation to high irradiance? Testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic Ficus |
| title_sort |
is hemiepiphytism an adaptation to high irradiance? testing seedling responses to light levels and drought in hemiepiphytic and non-hemiepiphytic ficus |
| publishDate |
2013 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00319317_v148_n1_p74_Hao http://hdl.handle.net/20.500.12110/paper_00319317_v148_n1_p74_Hao |
| work_keys_str_mv |
AT goldsteinguillermohernan ishemiepiphytismanadaptationtohighirradiancetestingseedlingresponsestolightlevelsanddroughtinhemiepiphyticandnonhemiepiphyticficus |
| _version_ |
1768542072016470016 |