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用土培盆栽试验研究了硫酸盐、硒酸盐单一及交互作用对小白菜生长及其硒生物有效性的影响.结果表明,单施硒时,适量硒(≤1.0 mg·kg~(-1))能促进小白菜地上部的生长,表现为小白菜株高和地上部干重分别较不施硒对照处理增加了8.4%和22.1%(p<0.05),但高剂量硒(≥2.5 mg·kg~(-1))却抑制其生长,小白菜株高和地上部干重分别较对照减少了0.4%、14.2%(2.5 mg·kg~(-1)Se)和15.8%、50.3%(5.0 mg·kg~(-1)Se).小白菜的根系对硒酸盐的胁迫更为敏感,单施硒处理小白菜根长和地下部干重均低于对照处理,且抑制作用随外源硒添加量的增加而增大,外源硒添加量为1.0、2.5、5.0 mg·kg~(-1)处理的小白菜的根长和地下部干重分别较对照下降了20.5%、28.3%、49.4%和29.2%、24.2%、58.5%.施硫能减缓硒对小白菜的胁迫,表现为相同硒剂量下,小白菜根长、地上和地下部干重均随外源硫剂量的增大而增加.另外,施硫处理小白菜叶绿素含量均显著高于相同硒剂量下的无硫处理,过氧化物酶活性却相反.相同硫剂量下,小白菜硒含量随外源硒添加量的增大而显著增大(p<0.05),且地上部对硒的吸收和富集能力均显著大于地下部(p<0.05).与此不同,施硫显著抑制小白菜对硒的吸收与富集(p<0.05),小白菜地上、地下部硒含量和富集系数(BCFSe-shoot、BCFSe-root)均随外源硫剂量的增大而减小.小白菜生物量与其体内硒含量、硒富集系数呈显著负相关.由此可见,硫酸盐是通过抑制硒吸收和富集及调控小白菜自身的生理代谢来减缓硒酸盐对小白菜生长的胁迫.硫酸盐与硒酸盐的相互作用受硫剂量、硒剂量及植株部位的影响.
The effects of sulfate and selenate on the growth and the bioavailability of selenium in Chinese cabbage were studied by pot culture experiments.The results showed that adequate selenium (≤1.0 mg · kg -1) ) Could promote the growth of aboveground part of Chinese cabbage. The results showed that the plant height and aboveground dry weight of Chinese cabbage increased 8.4% and 22.1% respectively (p <0.05), but high dose of selenium (≥2.5 mg · kg -1) decreased the plant height and shoot dry weight by 0.4%, 14.2% (2.5 mg · kg -1) Se and 15.8%, 50.3% 5.0 mg · kg -1 Se.) The root system of Chinese cabbage is more sensitive to selenate stress, the root length and the dry weight of the lower part of Chinese cabbage were all lower than those of the control, And the amount of source selenium added increased. The root length and underground dry weight of cabbage treated with 1.0, 2.5 and 5.0 mg · kg -1 of exogenous selenium decreased by 20.5% and 28.3% respectively compared with the control %, 49.4% and 29.2%, 24.2% and 58.5%, respectively. Applying sulfur can slow the selenium stress on the Chinese cabbage. The results showed that under the same selenium dosage, the root length, Increase and increase. In addition, the sulfur The chlorophyll content of Chinese cabbage was significantly higher than that under the same selenium dosage, but the activity of peroxidase was the opposite. Under the same sulfur dosage, the content of selenium in Chinese cabbage increased significantly with the addition of exogenous selenium (p <0.05), and the uptake and enrichment ability of selenium in shoots was significantly higher than that in the ground parts (p <0.05) .Sulfur application significantly inhibited the absorption and accumulation of selenium in Chinese cabbages (p <0.05) The contents of BCFSe-shoot and BCFSe-shoot in cabbage decreased with the increase of exogenous sulfur dose.The cabbage biomass had a significant negative correlation with its selenium content and selenium accumulation coefficient .Therefore, sulfate inhibits selenite stress on the growth of cabbage by inhibiting selenium absorption and enrichment and regulating the physiological metabolism of Chinese cabbage.The interaction between sulfate and selenate is affected by sulfur dosage, selenium dosage And plant parts of the impact.