| 不同密度甘肃马先蒿寄生和内生真菌互作对紫花针茅内源激素及生物碱含量的影响 |
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| 引用本文： | 鲍根生,宋梅玲,王玉琴,刘静,王宏生.不同密度甘肃马先蒿寄生和内生真菌互作对紫花针茅内源激素及生物碱含量的影响[J].草业学报,2020,29(4):147-156. |
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| 作者姓名： | 鲍根生 宋梅玲 王玉琴 刘静 王宏生 |
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| 作者单位： | 1.青海大学畜牧兽医科学院,青海 西宁 810016; 2.青海大学省部共建三江源生态与高原农牧业国家重点实验室,青海 西宁 810003; 3.兰州大学草地农业生态系统国家重点实验室,甘肃 兰州 730020 |
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| 基金项目： | 国家自然科学基金项目(31660690, 31700098)和青海省“高端创新人才千人计划”拔尖人才培养计划项目资助 |
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| 摘 要： | 根寄生植物是禾草生长过程中的一种生物逆境,禾草内生真菌能增强其对生物或非生物逆境的耐受能力;然而,有关禾草内生真菌对不同密度根寄生逆境下禾草生长、内源激素水平和生物碱含量变化的研究鲜有报道。基于此,通过开展温室盆栽试验,以建立根寄生关系的带菌(E+)和未带菌(E-)紫花针茅及根寄生植物-甘肃马先蒿为研究对象,比较E+和E-紫花针茅在不同甘肃马先蒿寄生强度下生长、内源激素和生物碱含量变化。结果表明,与未寄生紫花针茅相比,随着甘肃马先蒿密度增加,紫花针茅生物量降低80%,株高、分蘖数和根长均降低25%,吲哚乙酸、脱落酸含量分别增加43%和51%,细胞分裂素含量降低50%。内生真菌侵染显著提高紫花针茅生长特性,增加内源激素和生物碱含量;带菌紫花针茅在根寄生逆境下生物碱含量持续增加,同时甘肃马先蒿利用根部木质部通道可获取寄主内生真菌合成的生物碱。由此可见,内生真菌通过调控紫花针茅体内有关生长和逆境预警相关内源激素水平及改变生物碱含量的方式增强紫花针茅对甘肃马先蒿根寄生逆境的耐受能力,为利用禾草内生真菌共生体修复甘肃马先蒿型退化草地提供新视角。
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| 关 键 词： | 根寄生植物 内源激素 生物碱 内生真菌 紫花针茅 密度 |
| 收稿时间： | 2019-07-08 |
| 修稿时间： | 2019-10-10 |
Interactive effects of different densities of Pedicularis kansuensis parasitism and Epichloё endophyte infection on the endogenous hormone levels and alkaloid contents of Stipa purpurea |
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| BAO Gen-sheng,SONG Mei-ling,WANG Yu-qin,LIU Jing,WANG Hong-sheng.Interactive effects of different densities of Pedicularis kansuensis parasitism and Epichloё endophyte infection on the endogenous hormone levels and alkaloid contents of Stipa purpurea[J].Acta Prataculturae Sinica,2020,29(4):147-156. |
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| Authors: | BAO Gen-sheng SONG Mei-ling WANG Yu-qin LIU Jing WANG Hong-sheng |
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| Institution: | 1.Academy of Animal and Veterinary Medicine, Qinghai University, Xining 810016, China; 2.State Key Laboratory Plateau Ecology and Agriculture, Qinghai University, Xining 810003, China; 3.Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China |
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| Abstract: | Root hemiparasites of grasses in the natural environment impose a biotic stress on their hosts. Conversely, Epichloё endophytes enhance their hosts’ tolerance or resistance to biotic and abiotic stresses. However, only a few studies have explored the interactive effects of different densities of hemiparasite infection and the presence or absence of Epichloё endophyte on the growth, endogenous hormone levels and alkaloid contents of the host grasses. Therefore, we set up a two factor pot experiment with endophyte-infected (E+) and endophyte-free (E-) plants of Stipa purpurea as the host grass, grown without (control) or with one or three plants of the hemiparasite Pedicularis kansuensis. Various plant growth parameters and endogenous hormone levels were determined for E+ and E- S. purpurea, while alkaloid concentrations of endophyte-infected S. pupurea plants and their hemiparasites (where present) were measured. Comparing parasitized and unparasitized S. purpurea, biomass of parasitized plants was decreased 80%, plant height, tiller number and root length were reduced 25%, and indole-3-acetic acid and abscisic acid levels of S. purpurea were increased 43% and 51%, respectively. However, zeatin-riboside levels were decreased by 50%, while the growth parameters, and endogenous hormone levels of E+ host grasses were significantly higher than those of their E- counterparts. Furthermore, under parasitic stress, alkaloid production of Epichloё-endophyte-infected plants was enhanced, and alkaloids were transferred from E+ host grass plants to their root hemiparasites through the xylem bridge formed by haustoria. In conclusion, our results show that Epichloё endophyte has a potential role in improving its host grass resistance or tolerance to parasitic stress by up-regulating host grass alkaloid contents and endogenous hormone levels, especially those hormones typically sensitive to biotic stress. Our results also suggest that use of the Epichloё endophyte symbiont has potential as a tool to assist recovery of degraded grassland in the Qinghai Tibet Plateau where root hemiparasites are widely distributed. |
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| Keywords: | root hemiparasite endogenous hormone alkaloid Epichloë endophyte Stipa purpurea density |
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