• ISSN 1008-505X
  • CN 11-3996/S

外源钙缓解花生低温光合障碍的调控机制

Foliar calcium application alleviates cold stress-induced photosynthetic inhibition in peanut

  • 摘要:
      目的  北方春季低温冷害是限制花生生产的主要环境因素之一,钙素营养可提升花生耐冷性和光合碳同化作用,本研究进一步探究外源钙缓解花生低温光合障碍的调控机制。
      方法  以花生品种‘小白沙’为试验材料,在人工气候室内进行了盆栽培养试验。设常温喷清水对照(夜温/昼温为20℃/28℃,幼苗叶面喷清水);在低温胁迫(夜温/昼温为9℃/15℃)下,分别设幼苗叶面喷清水(+H2O)、喷15 mmol/L CaCl2 (+Ca)、喷施钙抑制剂(+EGTA)处理,共4个处理。将真叶展开一周的花生幼苗栽于盆中,连续两天进行叶面喷施处理,然后在低温胁迫下生长7天,恢复常温后再生长7天,共培养14天。于低温和常温处理期间,测定花生幼苗生长发育、光化学活性、非结构型碳水化合物以及活性氧积累。
      结果  低温胁迫抑制花生生长,导致叶片非结构型碳水化合物和活性氧(ROS)过量积累,同时造成严重的光损伤,表现为调节性能量耗散的量子产量Y (NPQ)和非调节性能量耗散的量子产量Y (NO)显著上升,PSI和PSII实际量子产量显著降低。外源Ca2+增加了花生幼苗株高、叶面积和叶绿素含量,也显著缓解了低温依赖性光损伤,避免了叶片中非结构型碳水化合物的过量积累,增强了花生光合作用水平;外源Ca2+有效降低了ROS过量积累,有效保护光合机构。
      结论  低温胁迫及恢复常温过程中,外源Ca2+可以通过有效激发花生生长发育和光化学活性,维持叶片中非结构型碳水化合物有效外运,降低非结构型碳水化合物和ROS过度积累,全面缓解低温对花生产生的光抑制。

     

    Abstract:
      Objectives  Chilling damage in early spring is one of the main environmental limiting factors in peanut production in northern China. Calcium has been proven to enhance chilling tolerance and photosynthetic carbon fixation in peanut, hence, we investigated the regulatory mechanisms underlying the alleviation effect of exogenous Ca to low temperature stress in peanut.
      Methods  Peanut cultivar ‘Xiaobaisha’ was used as the experimental material in the study conducted in an artificial climate chamber. The control room temperature was 20°C/28°C (night/day) with foliar spraying of ultrapure water. The low temperature stress was set as 9°C/15°C, with foliar spraying of ultrapure water (+H2O), 15 mmol/L CaCl2 (+Ca), or 5 mmol/L ethylene glycol tetraacetic acid (+EGTA). At one week of true leaf expansion, the peanut seedlings were grown in the vessels and foliar spray was treated for two consecutive days, then treated under low temperature stress for 7 days, followed by normal temperature for 7 days. The plant growth, photochemical activity, non-structural carbohydrates and reactive oxygen species accumulation were measured.
      Results  Low temperature stress inhibited peanut growth, leading to excessive accumulation of non-structural carbohydrates and reactive oxygen species (ROS) in peanut leaves. The low temperature stress also caused severe photo-damage such as significant increments of regulated-energy dissipation Y(NPQ) and unregulated energy dissipation Y(NO), and decrements of the unregulated energy dissipation of PSI Y(I) and PSII Y(II). Exogenous Ca2+ enhanced plant height, leaf area and relative chlorophyll concentration of peanut seedlings, and also significantly alleviated low temperature-induced photodamage, reduced excessive accumulation of non-structural carbohydrates in leaves, and enhanced photosynthesis in peanut. Further, exogenous Ca2+ reduced the excessive accumulation of ROS and protected photosynthetic apparatus effectively.
      Conclusions  During low temperature stress and normal temperature recovery, exogenous Ca2+ can alleviate chilling-induced photo-inhibition by effectively stimulating peanut growth and photochemical activities, maintaining non-structural carbohydrates efflux, and reducing excessive accumulation of non-structural carbohydrates and ROS.

     

/

返回文章
返回