伴矿景天春化临界温度及其生理响应初步研究

Preliminary Study on the Critical Vernalization Temperature and Physiological Responses of Sedum plumbizincicola

  • 摘要: 该研究通过控制伴矿景天(Sedum plumbizincicola X. H. Guo et S. B. Zhou ex L. H. Wu)生长时的温度及其持续时间,探明伴矿景天的春化临界条件及生理响应特征。本研究采用盆栽试验,将伴矿景天健壮种苗各8株进行以下处理:分别置于4、8和12 ℃恒温光照生长箱中进行14、21、28、35、42、49和56 d的低温预处理后移至23 ℃恒温光照生长箱中继续培养处理;恒温光照生长箱中始终23 ℃处理;4 ℃低温预处理123 d后移至室外自然环境处理;始终室外自然环境处理。结果表明,4 ℃低温预处理可促进伴矿景天开花,且随着低温预处理时间的延长,其首花日期提前,开花率提高。伴矿景天春化临界温度为4~8 ℃,其中4 ℃条件下其所需春化时间为35 d,49 d后其可完全春化。随着4 ℃低温预处理时间的增加(14~56 d),伴矿景天的茎粗和株高均显著增长,但其地上部生物量无显著差异。4 ℃低温预处理49 d后移至23 ℃恒温光照生长箱中继续培养,完全春化的伴矿景天在收获期的茎粗和株高均显著高于恒温光照生长箱中始终23 ℃处理,但地上部生物量无显著差异。与恒温光照生长箱中始终23 ℃处理相比,4 ℃低温预处理56 d后移至23 ℃恒温光照生长箱中继续培养可显著降低伴矿景天盛花期叶片的叶绿素和全氮含量,但可增加叶片的可溶性糖、淀粉和可溶性蛋白含量并提高碳氮比(C/N)值。本研究认为提高伴矿景天生长期间的环境温度可以有效抑制其春化过程,调控伴矿景天开花期,实现少开花甚至不开花,以实现持续生长和刈割,从而提高超积累植物对污染土壤中镉的吸取率。

     

    Abstract: Most Sedum plumbizincicola shoots will die after flowering, greatly affecting its growth and cadmium (Cd) uptake from polluted soils. Here, a pot experiment was conducted to investigate the vernalization conditions and physiological responses of Sedum to different temperature treatments of varying duration. The study established the following four experimental treatments: a) the Sedum robust seedlings were placed in a 4, 8, or 12 ℃ constant temperature and light growth chamber for 14, 21, 28, 35, 42, 49, or 56 days of low-temperature pre-treatment before being transferred to a 23 ℃ growth chamber for continued cultivation; b) the seedlings received 123 days of continuous 23 ℃ treatment in the incubator before transitioning to ambient conditions; c) the seedlings underwent 123 days of continuous 4 ℃ low-temperature pre-treatment followed by ambient adaptation; d) the seedlings of the control group maintained in outdoor ambient conditions. Eight healthy and robust Sedum seedlings were selected for each treatment. The experiment started on December 22, 2023 and was harvested on July 2, 2024. The results of the study show: The 4 ℃ low-temperature treatment promoted flowering, and the flowering date and rate gradually increased with increasing time in the low-temperature treatment, and the critical temperature of vernalization was 4-8 ℃; In the 4 ℃ treatment the vernalization time was 35 days, and 49 days were required for complete vernalization; From 14 to 56 days the 4 ℃ low-temperature treatment significantly increased plant stem diameter and height but had no significant effect on shoot biomass; After 49 days of the low-temperature treatment at 4 ℃ the stem diameter and plant height at harvest appeared to be higher than those in the consistent 23 ℃ treatment, but no significant difference was observed in shoot biomass between the two treatments; Compared to the consistent 23 ℃ treatment the chlorophyll and total nitrogen contents of leaves decreased significantly after 56 days in the 4 ℃ treatment during the full flowering period; In contrast, the foliar contents of soluble sugars, starch, soluble proteins, and the carbon-to-nitrogen ratio (C/N) were higher in the 4 ℃ treatment than the consistent 23 ℃ treatment. Therefore, increasing the ambient temperature during the growth period of Sedum can effectively inhibit the vernalization process. This provides a valuable basis for the regulation of the flowering period of S. plumbizincicola, the realization of less or no flowering, and the continuous growth and cutting, to increase the Cd phytoextraction efficiency of the hyperaccumulator in polluted soils.

     

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