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近年来国外学者发现杨树(Populus spp.)对硼表现出很强的富集能力和极强的耐受能力,但其耐硼胁迫的生理机制和种间差异仍不清楚。该研究通过两年的硼梯度控制试验,探讨了硼胁迫对欧洲黑杨杂交种俄罗斯杨(Populus russkii)和银白杨变种新疆杨(P.bolleca)的生长和生理指标的影响。结果表明,新疆杨的耐高硼能力高于俄罗斯杨,其高硼伤害阈值(EC10)为35 mg·kg–1,俄罗斯杨为19 mg·kg–1。两种杨树的过氧化氢酶(CAT)和愈创木酚过氧化物酶(Gu-POD)活性随硼浓度升高而升高,超过EC10后显著下降。尽管两种杨树的叶绿素含量和光化学效率在硼胁迫下降低,但抗硼胁迫能力较强的新疆杨仍然保持了较高的叶绿素a/b值和热耗散能力(非光化学淬灭升高),因此有效地保护了该树种的光合能力。两种杨树的可溶性糖含量随硼胁迫加重而适应性升高,以维持其抗渗透能力,但其叶片可溶性蛋白含量仅在中低强度的硼胁迫条件下有所升高。该研究明确了两个富集硼的杨树种对高硼胁迫的生理响应及其种间差异。
In recent years, foreign scholars have found that poplar (Populus spp.) Shows a strong enrichment ability and strong tolerance to boron, but the physiological mechanism and interspecies difference of boron tolerance are still unclear. This study investigated the effects of boron stress on the growth and physiological indices of poplar (Populus russkii) and P. bolleca (European poplar) Populus hybrids through two years of boron gradient control experiments. The results showed that the high boron tolerance of Xinjiang poplar was higher than that of Russian poplar, and its high boron injury threshold (EC10) was 35 mg · kg-1 and that of Russian poplar was 19 mg · kg-1. Catalase (CAT) and guaiacolperoxidase (Gu-POD) activities of the two poplar trees increased with the increase of boron concentration, but decreased significantly after EC10. Although the chlorophyll content and photochemical efficiency of the two poplar trees decreased under boron stress, the Xinjiang poplar with stronger ability to resist boron stress still maintained higher chlorophyll a / b value and heat dissipation capacity (non-photochemical quenching increased ), Thus effectively protecting the photosynthetic capacity of the tree species. Soluble sugar content of both poplar trees increased adaptively with the increase of boron stress in order to maintain their anti-infiltration ability, but their leaf soluble protein content increased only under moderate and low boron stress. The study identified the physiological responses of two boron-enriched poplar species to high boron stress and their interspecific differences.