Delftia sp.B9对镉胁迫下水稻种子萌发及幼苗镉积累的影响

为探讨耐镉细菌Delftia sp. B9对镉(Cd)胁迫下水稻种子萌发及幼苗吸收积累Cd的影响,以两种水稻(华润2号、深两优5814)为材料,研究水稻在3种Cd胁迫浓度(0、0.01、0.1 mg·L~(-1))下添加Delftia sp. B9菌液对水稻幼苗生长和积累Cd的影响。结果表明:Cd胁迫浓度为0.1 mg·L~(-1)时,Delftia sp. B9产吲哚乙酸(IAA)能力与对照相比显著减少2.87 mg·L~(-1),产铁载体相对含量下降17.34%。Cd胁迫浓度为0.1 mg·L~(-1)时,添加Delftia sp. B9菌液对水稻种子萌发和耐性系数有显著的促进作用。Cd胁迫下添加Delftia sp. B9菌液的处理(T3)与对照(T1)相比能显著增加两种水稻幼苗的根长、株高、叶绿素a和叶绿素b含量。添加Delftia sp.B9显著降低两种水稻幼苗根、茎、叶中Cd含量,使华润2号根、茎、叶中Cd含量分别降低63.81%、67.59%、70.84%,使深两优5814根、茎、叶中Cd含量分别降低75.95%、74.84%、80.81%。研究表明,耐镉细菌Delftia sp. B9可促进Cd胁迫下水稻种子萌发,增加水稻幼苗叶绿素含量和株高,并降低根、茎、叶中Cd含量。

Effects of Delftia sp. B9 on rice seed germination and cadmium accumulation in rice seedlings under Cd stress

To explore the effects of Delftia sp. B9 strain on seed germination and Cd accumulation in rice seedlings, three different levels of Cd stress (0, 0.01, and 0.1 mg·L^-1) were applied to two rice varieties (Huarun No. 2 and Shenliangyou No. 5814) following inoculation of Delftia sp. B9 strain. The results showed that Delftia sp. B9 produced 2.87 mg·L^-1 less indoleacetic acid under 0.1 mg·L^-1 Cd stress, whereas the siderophore production decreased by 17.34%, accordingly. The addition of Delftia sp. B9 had a significant role in promoting rice seed germination and tolerance coefficient under 0.1 mg·L^-1 Cd stress. Exposure to Delftia sp. B9 stress (T3) significantly increased the root length, height, and chlorophyll a and chlorophyll b content of the two rice varieties compared to that of the control (T1). After the addition of Delftia sp. B9, the Cd concentrations in the roots, stems, and leaves of Huarun No. 2 were decreased by 63.81%, 67.59%, and 70.84%, respectively, and correspondingly decreased by 75.95%, 74.84%, and 80.81% in Shenliangyou No.5814. The results showed that the Cd-tolerant bacteria Delftia sp. B9 promoted germination of rice seed and increase chlorophyll content and plant height of rice seedlings under Cd stress, while reducing Cd content in the roots, stems, and leaves of rice seedlings.