Ca2+信号在DIDS(4,4-二异硫氰-2,2-二磺酸)抑制茶树吸收氟的功能研究

[目的] 茶叶富含有利于人体健康的多糖、咖啡因、多酚和氨基酸等有益物质,但茶树能够在正常含氟(F)土壤中超积累F,导致过量饮茶易诱发氟斑牙和氟骨病的发生。因此,降低茶叶中的F含量对人体健康具有重要意义。[方法] 以‘福鼎’大白茶茶籽为研究对象,通过激光共聚焦和非损伤微测技术研究Ca2+信号在阴离子通道抑制剂4,4-二异硫氰-2,2-二磺酸(DIDS)抑制茶树吸收F过程中的作用。[结果] 随着DIDS前处理时间的延长,显著削弱了茶树对F的吸收富集。同时DIDS调控了茶树根尖成熟区区域A和B的Ca2+荧光强度的反向变化,区域A从858.42降低至565.42 AU,区域B从499.28升至570.42 AU;同时DIDS显著刺激了茶树根部成熟区Ca2+的跨膜运输,平均外排量从静息量的9.43提高至350.35 pmol？cm-2？s-1。此外,Ca2+螯合剂EGTA前处理分别削弱了DIDS对Ca2+信号强度的增强和对F的吸收抑制作用。[结论] 茶树根尖成熟区Ca2+信号可能通过跨膜运输参与了DIDS抑制茶树对F的吸收富集。
[Objectives] Tea plant is beneficial for people’s health due to the elements of polysaccharide, caffeine, polyphenol and amino acid. However, tea plants(Camellia sinensis L.)can accumulate large amounts of fuoride(F), while the over-intake of fluoride through drinking tea can cause dental fluorosis and fluorosis of bone. Therefore, the research of reducing F content in tea plants has an important effect on human’s body health.[Methods] In this study, ‘Fuding’ variety of tea plant was used as materials to carry out the experiments. Using laser confocal scanning microscopy(LCSM)and Non-invasive Micro-test Technique(NMT)approaches, the role of Ca2+ signal on DIDS(4, 4-diisothiocyanostilbene-2, 2-disulfonic acid)-inhibited F accumulation in tea plants was investigated.[Results] The pretreatment of DIDS significantly inhibited F accumulation in tea plants. DIDS altered Ca2+ fluorescence intensity in the mature zone of tea root, which decreased from 858.42 to 565.42 AU in region A and increased from 499.28 to 570.42 AU in region B. In addition, DIDS significantly stimulated Ca2+ efflux from the root mature zone cells, ranging from 9.43 to 350.35 pmol？cm-2？s-1. Whilst, EGTA pretreatment inhibited DIDS-induced the increase of Ca2+ fluorescence intensity in tea lateral roots, and also significantly impaired DIDS-decreased F accumulation in tea plants.[Conclusions] Taken together, the endogenous Ca2+ in the mature zone of tea root might participate in the F accumulation in tea plants inhibited by the pretreatment of DIDS