| 莱茵衣藻活细胞制剂缓解小麦幼苗镉胁迫的效应与机制 |
| 摘要点击 894 全文点击 127 投稿时间：2024-02-22 修订日期：2024-05-11 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 镉（Cd）胁迫 小麦幼苗 微藻活细胞制剂 抗氧化系统 光合作用 重金属吸收和积累 |
| 英文关键词 cadmium （Cd） stress wheat seedling microalgal living cell agent antioxidant system photosynthesis heavy metal uptake and accumulation |
| 作者 | 单位 | E-mail | | 雷春燕 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | vaeleicy@163.com | | 李亚男 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 梁梦静 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 杨泽 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 孙岩 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 季春丽 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 张春辉 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 李润植 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | | | 孙希平 | 山西农业大学农学院, 山西省特用作物遗传与代谢工程研究中心, 太谷 030801 | sxpljj@126.com | | 崔红利 | 中国科学院烟台海岸带研究所, 海岸带生物学与生物资源利用重点实验室, 烟台 264003 | cuihongli@sxau.edu.cn |
|
| 中文摘要 |
| 重金属镉（Cd）污染不仅导致农作物减产,而且可通过食物链传递和积累,对人类健康构成威胁. 减少作物对Cd吸收和富集,以及提高Cd胁迫抗性是绿色健康农业可持续发展的重要议题. 为建立应用微藻防控Cd污染和提高作物抗逆性的新农艺技术,选用莱茵衣藻（Chlamydomonas reinhardtii）和小麦（Triticum aestivum）开展系统研究,以期阐明微藻阻滞Cd迁移和增强作物Cd胁迫抗性的效果及作用机制. 供试作物为冬小麦品种晋麦182（JM182）和春小麦品种津春6号（JC6）. 水培试验设置2个剂量的Cd胁迫即50 mg·L-1（Cd50）和100 mg·L-1（Cd100）. 制备2种剂量的莱茵衣藻活细胞制剂即藻液D680为1.0 （A1.0）和D680为2.0 （A2.0）. 测定小麦幼苗生长、生理响应、Cd吸收、转运和积累,以及重金属转运相关基因转录表达等参数. 结果表明,Cd胁迫严重抑制小麦幼苗生长. 施用莱茵衣藻活细胞制剂可显著增加小麦幼苗光合色素含量和激活抗氧化酶系统活性,显著减轻Cd胁迫对小麦幼苗的伤害. 此外,莱茵衣藻活细胞制剂A1.0和A2.0处理均能下调小麦幼苗重金属吸收和转运相关基因（TaHMA2、TaHMA3、TaNramp1和TaLCT1）的转录表达. 小麦幼苗Cd含量测定显示,Cd50和Cd100胁迫分别导致JC6春小麦幼苗Cd富集量达185.01 mg·kg-1和342.11 mg·kg-1,Cd在JM182冬小麦幼苗积累量达176.76 mg·kg-1和317.65 mg·kg-1. 显然,与JM182品种相比,JC6小麦品种易于吸收和富集Cd. 重要的是,微藻活细胞制剂处理则显著减少2个品种小麦幼苗Cd积累量. 与Cd50处理的JC6品种小麦幼苗相比,A2.0处理的JC6品种小麦幼苗根部和茎叶部的Cd积累量分别下降了76.80%和66.91%,且Cd从根部向茎叶部转移率减低了27.58%. 结果显示,莱茵衣藻活细胞制剂通过调控重金属吸收和转运相关基因的表达,显著减少小麦幼苗对Cd的吸收和从根部向茎叶器官的转运与积累. 莱茵衣藻活细胞制剂亦可通过激活抗氧化系统及增强光合作用等,有效缓解Cd对小麦幼苗的伤害,进而促进小麦生长发育. 研究发现可为微藻活细胞制剂用作生物肥或生物刺激剂以阻滞重金属污染物的迁移和增强植物对重金属的抗逆性提供了科学依据和新策略. |
| 英文摘要 |
| Cadmium （Cd） pollution not only leads to the reduction in crop yields but also migrates and accumulates through the food chain, thus posing a threat to human health. It is an important issue to reduce Cd uptake and enrichment in crops and increase crop resistance to Cd stress for sustainable development of green-health agriculture. To establish a novel agronomic technique using microalgae to control Cd pollution and improve crop stress resistance, the microalga Chlamydomonas reinhardtii and wheat （Triticum aestivum）were employed for systematic investigation so as to the elucidate effects and mechanism of microalgae in blocking Cd migration and enhancing crop resistance to Cd stress. The test crop materials were the winter wheat variety JM182 and spring wheat variety JC6. Hydroponic experiments were used to simulate Cd stress at two dosages, 50 mg·L-1 （Cd50） and 100 mg·L-1 （Cd100）. Two different dosages of C. reinhardtii living cell agents, i.e., the microalgal cell cultures with D680 = 1.0 （A1.0） and D680 = 2.0 （A2.0）, were prepared using conventional microalgal-cultivation methods and subsequently used to treat wheat seedlings under Cd stress. Several physiological and biochemical parameters were determined for wheat seedlings under two doses of Cd stress, respectively, including growth features, photosynthesis, cellular antioxidant enzyme activity, Cd uptake, transportation and accumulation, and transcriptions of the genes associated with heavy metal transportation. The results showed that Cd stress crucially inhibited the growth of wheat seedlings. However, the application of C. reinhardtii living cell agents significantly increased the contents of photosynthetic pigments （chlorophyll a, chlorophyll b, and carotenoids） and activated the antioxidant enzyme system activities （SOD, POD, CAT, GSH, and APX）. The microalgal living cell agents also reduced the damage of Cd stress on wheat seedling growth. Moreover, both doses （A1.0 and A2.0） of C. reinhardtii living cell agents downregulated the expression of the genes related to heavy metal absorption and transportation （TaHMA2, TaHMA3, TaNramp1,and TaLCT1）. Analysis of Cd contents indicated that Cd stress resulted in Cd accumulation in wheat seedlings, with a higher level of Cd in JC6 than in JM182 under both doses of Cd stresses. Cd50 and Cd100 stresses led to Cd levels up to 185.01 mg·kg-1 and 342.11 mg·kg-1 in JC6 wheat seedlings and 176.76 mg·kg-1 and 317.65 mg·kg-1 in JM182, respectively. Notably, the addition of the microalgal living cell agent significantly reduced Cd enrichment in wheat seedlings of both varieties under Cd stresses. Compared to the Cd level in JC6 wheat seedlings under Cd50 stress, the Cd accumulation level in roots and stem-leaf parts of A2.0-treated JC6 wheat seedlings was reduced by 76.80% and 66.91%, respectively, followed by a 27.58% diminution of Cd transport rate from roots toward stem-leaf parts. Collectively, microalgal living cell agents could remarkably reduce Cd uptake, accumulation, and transportation from roots to stem-leaf organs of wheat seedlings by down-regulating gene expressions involved in heavy metal absorption and transportation. The microalgal living cell agent can also activate the antioxidant system and increase photosynthesis, thus mitigating Cd toxicity and promoting the growth and development of wheat seedlings. The present findings provide a scientific basis and new strategy for using microalgal living cell agents as bio-fertilizers or bio-stimulants to impede migration of heavy metal pollutants and enhance plant resistance to heavy metal stresses. |
|
|
|
