Cytokinin-producing, plant growth-promoting rhizobacteria that confer resistance to drought stress in Platycladus orientalis container seedlings
Cytokinin-producing, plant growth-promoting rhizobacteria that confer resistance to drought stress in Platycladus orientalis container seedlings
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DOI：
10.1007/s00253-013-5193-2
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发表时间：
2013-10-01
影响因子：
5
通讯作者：
Ma, Bingyao
中科院分区：
文献类型：
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作者：
Liu, Fangchun;Xing, Shangjun;Ma, Bingyao
植物根际促生菌（PGPR）促进植物生长的机制之一是产生植物生长调节物质，特别是细胞分裂素。然而，有关细胞分裂素产生的PGPR接种对生长和水分胁迫的森林容器苗在干旱条件下的一致性的信息很少。研究了枯草芽孢杆菌对水分胁迫条件下植物激素浓度、抗旱性和生长的影响。在水分充足的条件下，接种的侧柏幼苗在干旱胁迫下叶片相对含水量和叶水势均高于未接种的。无论供水水平如何，B都显著增加了根系分泌物，即糖、氨基酸和有机酸。枯草杆菌接种水分胁迫使地上部细胞分裂素含量降低39.14%。然而，接种减少这一赤字只有10.22%。脱落酸（阿坝）浓度的升高与侧柏地上部细胞分裂素水平的升高有关。B显著提高了气孔导度。在充分浇水的幼苗中接种枯草芽孢杆菌。但细胞分裂素对气孔导度的促进作用受到抑制，这可能是由于细胞分裂素和阿坝的共同作用所致。B。结果表明，接种枯草芽孢杆菌后，水分充足和干旱条件下的幼苗地上部干重分别增加34.85%和19.23%，根系干重分别增加15.445%和13.99%。因此，根/冠比显着降低，表明PGPR对地上部生长比根更大的好处。因此，在容器苗中接种产生细胞分裂素的PGPR可以缓解干旱胁迫并干扰对新梢生长的抑制，显示出在干旱环境中作为干旱胁迫抑制剂的真实的潜力。
One of the proposed mechanisms through which plant growth-promoting rhizobacteria (PGPR) enhance plant growth is the production of plant growth regulators, especially cytokinin. However, little information is available regarding cytokinin-producing PGPR inoculation on growth and water stress consistence of forest container seedlings under drought condition. This study determined the effects of Bacillus subtilis on hormone concentration, drought resistance, and plant growth under water-stressed conditions. Although no significant difference was observed under well-watered conditions, leaves of inoculated Platycladus orientalis (oriental thuja) seedlings under drought stress had higher relative water content and leaf water potential compared with those of noninoculated ones. Regardless of water supply levels, the root exudates, namely sugars, amino acids and organic acids, significantly increased because of B. subtilis inoculation. Water stress reduced shoot cytokinins by 39.14 %. However, inoculation decreased this deficit to only 10.22 %. The elevated levels of cytokinins in P. orientalis shoot were associated with higher concentration of abscisic acid (ABA). Stomatal conductance was significantly increased by B. subtilis inoculation in well-watered seedlings. However, the promoting effect of cytokinins on stomatal conductance was hampered, possibly by the combined action of elevated cytokinins and ABA. B. subtilis inoculation increased the shoot dry weight of well-watered and drought seedlings by 34.85 and 19.23 %, as well as the root by 15.445 and 13.99 %, respectively. Consequently, the root/shoot ratio significantly decreased, indicative of the greater benefits of PGPR on shoot growth than root. Thus, inoculation of cytokinin-producing PGPR in container seedlings can alleviate the drought stress and interfere with the suppression of shoot growth, showing a real potential to perform as a drought stress inhibitor in arid environments.