{"title":"Influence of light intensity on the responses of seedlings of neotropical tree species to nitrogen source","authors":"","doi":"10.1016/j.envexpbot.2024.106007","DOIUrl":null,"url":null,"abstract":"<div><div>Light intensity plays a crucial role in N uptake and assimilation in plants, but its interaction with different N sources is overlooked. Considering the high energy required for N assimilation, it is hypothesised that low light is critical for the seedling development with both N sources, but with increased light intensity, growing with nitrate (NO<sub>3</sub><sup>-</sup>) becomes favourable in relation to ammonium (NH<sub>4</sub><sup>+</sup>). Seedlings of <em>Cecropia pachystachya</em> (pioneer), <em>Guarea kunthiana</em> (shade-tolerant, understory) and <em>Cariniana estrellensis</em> (shade-tolerant, canopy) were grown in hydroponic medium with NO<sub>3</sub><sup>-</sup> or NH<sub>4</sub><sup>+</sup> as the sole N source and subjected to low (LL) or high light (HL) for 60 days. All three species showed a decrease in growth when cultivated with NH<sub>4</sub><sup>+</sup>, compared to NO<sub>3</sub><sup>-</sup>, under HL, but not under LL. The decrease in biomass reached 54 % in <em>C. pachystachya</em>, 36 % in <em>G. kunthiana</em> and 26 % in <em>C. estrellensis</em>. Growth reduction was associated with stomatal limitation of photosynthesis and reduced leaf area in <em>C. pachystachya</em>, and with non-stomatal limitation of photosynthesis and oxidative stress in <em>G. kunthiana</em>. Cation uptake was negatively affected by NH<sub>4</sub><sup>+</sup> in all species. <em>Cariniana estrellensis</em> showed no photosynthetic limitation and showed a higher tolerance to NH<sub>4</sub><sup>+</sup> under HL in terms of nutrient content. In conclusion, neither N source significantly favors seedling development under LL, while NH<sub>4</sub><sup>+</sup> is considerably more unfavorable for seedling development than NO<sub>3</sub><sup>-</sup> under HL.</div></div>","PeriodicalId":11758,"journal":{"name":"Environmental and Experimental Botany","volume":null,"pages":null},"PeriodicalIF":4.5000,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Environmental and Experimental Botany","FirstCategoryId":"99","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0098847224003654","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Light intensity plays a crucial role in N uptake and assimilation in plants, but its interaction with different N sources is overlooked. Considering the high energy required for N assimilation, it is hypothesised that low light is critical for the seedling development with both N sources, but with increased light intensity, growing with nitrate (NO3-) becomes favourable in relation to ammonium (NH4+). Seedlings of Cecropia pachystachya (pioneer), Guarea kunthiana (shade-tolerant, understory) and Cariniana estrellensis (shade-tolerant, canopy) were grown in hydroponic medium with NO3- or NH4+ as the sole N source and subjected to low (LL) or high light (HL) for 60 days. All three species showed a decrease in growth when cultivated with NH4+, compared to NO3-, under HL, but not under LL. The decrease in biomass reached 54 % in C. pachystachya, 36 % in G. kunthiana and 26 % in C. estrellensis. Growth reduction was associated with stomatal limitation of photosynthesis and reduced leaf area in C. pachystachya, and with non-stomatal limitation of photosynthesis and oxidative stress in G. kunthiana. Cation uptake was negatively affected by NH4+ in all species. Cariniana estrellensis showed no photosynthetic limitation and showed a higher tolerance to NH4+ under HL in terms of nutrient content. In conclusion, neither N source significantly favors seedling development under LL, while NH4+ is considerably more unfavorable for seedling development than NO3- under HL.
期刊介绍:
Environmental and Experimental Botany (EEB) publishes research papers on the physical, chemical, biological, molecular mechanisms and processes involved in the responses of plants to their environment.
In addition to research papers, the journal includes review articles. Submission is in agreement with the Editors-in-Chief.
The Journal also publishes special issues which are built by invited guest editors and are related to the main themes of EEB.
The areas covered by the Journal include:
(1) Responses of plants to heavy metals and pollutants
(2) Plant/water interactions (salinity, drought, flooding)
(3) Responses of plants to radiations ranging from UV-B to infrared
(4) Plant/atmosphere relations (ozone, CO2 , temperature)
(5) Global change impacts on plant ecophysiology
(6) Biotic interactions involving environmental factors.