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    黄小辉, 吴焦焦, 冯大兰, 孙向阳. 缺钾胁迫对核桃幼苗生长及生理特性的影响[J]. 北京林业大学学报, 2022, 44(8): 23-30. DOI: 10.12171/j.1000-1522.20210020
    引用本文: 黄小辉, 吴焦焦, 冯大兰, 孙向阳. 缺钾胁迫对核桃幼苗生长及生理特性的影响[J]. 北京林业大学学报, 2022, 44(8): 23-30. DOI: 10.12171/j.1000-1522.20210020
    Huang Xiaohui, Wu Jiaojiao, Feng Dalan, Sun Xiangyang. Effects of potassium deficient stress on growth and physiological characteristics of walnut seedlings[J]. Journal of Beijing Forestry University, 2022, 44(8): 23-30. DOI: 10.12171/j.1000-1522.20210020
    Citation: Huang Xiaohui, Wu Jiaojiao, Feng Dalan, Sun Xiangyang. Effects of potassium deficient stress on growth and physiological characteristics of walnut seedlings[J]. Journal of Beijing Forestry University, 2022, 44(8): 23-30. DOI: 10.12171/j.1000-1522.20210020

    缺钾胁迫对核桃幼苗生长及生理特性的影响

    Effects of potassium deficient stress on growth and physiological characteristics of walnut seedlings

    • 摘要:
        目的  探讨核桃在短期缺钾胁迫下的适应机理。
        方法  以核桃幼苗为研究对象,设置为期75 d不同程度的缺钾处理:对照(CK)、中度缺钾(MK)和重度缺钾(SK),每隔15 d进行相关指标测定,分析缺钾胁迫对核桃幼苗生长和生理特性的影响。
        结果  (1)在缺钾胁迫下,核桃幼苗地上部分生物量、根系生物量、叶绿素a、叶绿素b和类胡萝卜素含量均显著低于CK,且总体上随着缺钾程度的加重和处理时间的延长下降更明显;(2)相比于CK处理,MK和SK处理后期(60 ~ 75 d)核桃幼苗的最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSⅡ)、电子传递速率(ETR)和光化学猝灭系数(qP)显著下降;(3)随着处理时间的延长,不同缺钾处理下的核桃幼苗中过氧化氢酶(CAT)先上升后下降,MK、SK和CK处理中分别在30、45和60 d时出现最大值;MK和SK处理使超氧化物歧化酶(SOD)活性增加,而SK处理降低了过氧化物酶(POD)活性;处理中期(30 d)后,核桃幼苗中丙二醛(MDA)含量随胁迫程度加深而升高。
        结论  核桃受到缺钾胁迫后,根系和地上部分生长以及光合色素的合成均受到明显影响,但核桃能通过自身调节,加大对根部的投入,以提高吸收能力;并通过增加热耗散来消耗PSⅡ反应中心的过剩激发能,减少胁迫对光合机构的损害,调动体内的酶促抗氧化系统,对缺钾胁迫的伤害产生一定的抵抗能力。

       

      Abstract:
        Objective  The adaptive mechanism of walnut was explored under short-term potassium stress.
        Method  Walnut seedlings were treated with different levels of potassium deficiency for 75 d: control (CK), moderate potassium deficiency (MK) and severe potassium deficiency (SK), respectively. The related indexes were measured every 15 d, and the effects of potassium deficiency stress on the growth and physiology of walnut seedlings were analyzed.
        Result  (1) Under K deficiency stress, the aboveground biomass, root biomass, chlorophyll a, chlorophyll b and carotenoid contents of walnut seedlings were significantly lower than those of CK (control treatment), and the overall decrease was more obvious with the aggravation of K deficiency degree and the extension of treatment time. (2) Compared with CK treatment, Fv/Fm, ΦPSⅡ, ETR and qP of walnut seedlings decreased significantly at the late stage of MK and SK (60−75 d). (3) As the processing time increased, CAT of walnut seedlings increased at first and then decreased under different K deficiency treatments. MK, SK and CK treatments reached the maximum at 30, 45 and 60 d, respectively. SOD activity of MK and SK increased, but POD activity decreased under severe K deficiency. From the middle stage of treatment (30 d) , the content of MDA in walnut seedlings increased with the increase of stress degree.
        Conclusion  The growth of root and aboveground parts, and the synthesis of photosynthetic pigments of walnut are significantly affected by potassium deficiency stress. However, the walnut could increase the input to root system through self-regulation to improve its absorption capacity, and consume the excess excitation energy of PSⅡ reaction center by increasing heat dissipation, in order to reduce the damage of stress on photosynthetic apparatus. Furtherly, the walnut could mobilize its enzymatic antioxidant system, and produce certain resistance to potassium deficiency stress.

       

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