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酸、镉胁迫对金丝草种子萌发、幼苗生长及亚显微结构的影响
引用本文:赵雅曼,陈顺钰,李宗勋,李启艳,侯晓龙,蔡丽平.酸、镉胁迫对金丝草种子萌发、幼苗生长及亚显微结构的影响[J].草业学报,2019,28(12):63-74.
作者姓名:赵雅曼  陈顺钰  李宗勋  李启艳  侯晓龙  蔡丽平
作者单位:1.福建农林大学林学院,福建 福州 350002; 2.海峡两岸红壤区水土保持协同创新中心,福建 福州 350002; 3.南方红壤区水土保持国家林业和草原局重点实验室,福建 福州 350002
基金项目:福建省科技厅重点项目(2017Y0001),福建省环保科技计划项目(2018R012)和福建农林大学科技创新专项基金项目(CXZX2018126; CXZX2018137)资助
摘    要:金丝草可在土壤酸化和镉污染的矿区正常生长,其可能对酸和镉(Cd)胁迫具有特殊的响应策略。为此,以金丝草种子为试验材料,在人工气候箱中进行种子萌发试验,设置不同酸(pH 5.5、4.5、3.5)和镉(5、10、20 mg·L-1)胁迫处理,分析不同胁迫条件下金丝草种子萌发、幼苗生长、根系质膜完整性及芽亚显微结构等指标的差异。结果表明:酸胁迫可提高金丝草种子发芽率,不同酸胁迫处理其发芽率均与对照无显著差异(P>0.05);随pH的逐渐减小,金丝草萌发指标呈减小趋势,pH 3.5处理,金丝草种子除发芽率外的其他萌发指标均显著小于对照(P<0.05);随着Cd浓度的增加,金丝草种子萌发和幼苗生长指标值均呈逐渐减小的趋势,表现出抑制作用,但Cd 20 mg·L-1处理金丝草种子发芽率仍可达40%以上。相关性分析和隶属函数值分析发现,pH大于3.5,Cd浓度小于10 mg·L-1对金丝草种子萌发和幼苗生长无显著影响,但随pH的进一步减小和Cd浓度的提高,对金丝草种子萌发和幼苗生长抑制作用明显,根尖质膜和芽亚显微结构造成较大损害,出现细胞器膜破裂和细胞空泡化等现象。综上,金丝草种子萌发对酸和镉胁迫有较强耐性,表现出轻度酸和镉胁迫对种子萌发和幼苗生长促进,而强酸和镉胁迫则抑制。

关 键 词:金丝草  胁迫  种子萌发  亚显微结构  质膜完整性  
收稿时间:2019-06-10

Effects of acid and cadmium stresses on seed germination,seedling growth,and submicroscopic structure of Pogonatherum crinitum
ZHAO Ya-man,CHEN Shun-yu,LI Zong-xun,LI Qi-yan,HOU Xiao-long,CAI Li-ping.Effects of acid and cadmium stresses on seed germination,seedling growth,and submicroscopic structure of Pogonatherum crinitum[J].Acta Prataculturae Sinica,2019,28(12):63-74.
Authors:ZHAO Ya-man  CHEN Shun-yu  LI Zong-xun  LI Qi-yan  HOU Xiao-long  CAI Li-ping
Institution:1.College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China; 2.Co-innovation Center for Soil and Water Conservation in Red Soil Region of the Cross-straits, Fuzhou 350002, China; 3.Key Laboratory of the State Forestry and Grassland Administration for Soil and Water Conservation in Southern Red Soil Region, Fuzhou 350002, China
Abstract:Pogonatherum crinitum can grow normally in mining areas with soil acidification and cadmium contamination. It may therefore be inferred that this plant species has special adaptations to soil acidity and cadmium stresses. Germination experiments with P. crinitum seed were carried out in an artificial climate chamber under different acidity (pH 5.5, 4.5, 3.5) and cadmium (5, 10, 20 mg·L-1 Cd2+) stress treatments. Differences in seed germination, seedling growth, plasma membrane integrity of roots and submicroscopic structure of P. crinitum between different stress treatments were measured and compared. It was found acid stress improved the germination rate of the seeds, and there was no significant difference between acid stress treatments and the control for germination rate (P>0.05). The germination index of P. crinitum showed a gradual decreasing trend with decrease of pH. In the treatment pH 3.5, other germination indexes except for germination rate were significantly reduced compared with those of the Control (P<0.05). With increased Cd concentration, the seed germination and seedling growth gradually decreased and were eventually inhibited. However, the germination rate of seeds treated with 20 mg·L-1 Cd was still greater than 40%. Analysis of correlation and membership functions indicated that when the pH value is greater than 3.5 and Cd concentration lower that 10 mg·L-1, the seed germination and seedling growth will not be affected. However, with the decrease of pH value and the increase of Cd concentration, the seed germination and seedling growth were significantly inhibited, causing obvious damage to the plasmalemma of root tip cells and submicroscopic structure of buds, which resulted in rupture of organelle membranes and cell vacuolation. In summary, our results showed that seed germination and seedling growth of P. crinitum can be promoted by mild acid and cadmium stress and inversely inhibited by strong acid and Cd stresses.
Keywords:Pogonatherum crinitum  stress  seed germination  submicroscopic structure  plasma membrane integrity  
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