| .镉胁迫对杨树光合特性的影响[J].农业环境科学学报,2013,32(3):. |
| 镉胁迫对杨树光合特性的影响 |
| Effects of Cadmium on Photosynthetic Gas Exchange and Chlorophyll Fluorescence of Two Species of Poplar |
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| DOI：10.11654/jaes.2013.03.020 |
| 中文关键词: 镉胁迫 杨树 气体交换参数 叶绿素荧光参数 叶绿素含量 |
| 英文关键词: Cd stress poplar photosynthetic gas exchange chlorophyll fluorescence parameters chlorophyll contents |
| 基金项目: |
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| 摘要点击次数: 2201 |
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| 中文摘要: |
| 以灰杨和青杨为试验材料，以土壤、蛭石、蚯蚓粪（V∶V∶V=3∶1∶1）混合物为盆栽基质，设置 0（CK）、 20、 70、 150、 300 、500 mg·kg-1 6种土壤镉浓度，研究了土壤镉胁迫对杨树幼苗生物量、气体交换参数、叶绿素荧光参数和光合色素含量及镉积累量的影响。结果表明，当镉胁迫浓度为20 mg·kg-1时，杨树幼苗生长受到的抑制作用较小；高镉浓度（≥70 mg·kg-1）胁迫下，杨树幼苗的生长受到显著抑制。杨树幼苗不同器官对镉的积累浓度为：根>叶>茎。两种杨树幼苗的生物富集系数（BFC）在镉胁迫浓度为20 mg·kg-1下最大，500 mg·kg-1下最小，灰杨幼苗各器官的BCF均大于青杨；两种杨树幼苗的转移系数（TF）大致相当，在镉胁迫浓度为70 mg·kg-1下达到最大值。随着镉胁迫浓度（20~500 mg·kg-1）的增大，两种杨树幼苗叶片中叶绿素a、叶绿素b、总叶绿素的含量整体均呈下降趋势，当镉胁迫浓度为500 mg·kg-1时下降到最小值；灰杨幼苗叶片中叶绿素a/b值随镉胁迫浓度的增加而增加，但变化不显著；青杨中叶绿素a/b值先降低后升高，但各处理组均显著低于对照组。杨树幼苗叶片光合作用下降的主要原因是非气孔因素，气体交换参数Pn、Ts、Gs随着镉胁迫浓度的升高而降低，而Ci却随镉胁迫浓度的升高而升高；最大光化学量子产量（Fv/Fm）和PSⅡ潜在活性（Fv /F0）整体呈下降的趋势，且变化差异显著。当镉浓度为500 mg·kg-1时，光合作用最低。 通过对杨树幼苗光合作用各参数抑制率的比较发现，不同杨树品种之间耐镉能力存在一定的差异，灰杨幼苗生长受镉胁迫的抑制程度小于青杨。 |
| 英文摘要: |
| The pot experiment was adopted to study the effects of cadmium（Cd） on biomass, photosynthesis, chlorophyll fluorescence characteristics, chlorophyll content and the accumulation of cadmium in grey poplars（Populus×canescens） and cathay poplars（Populus pseudo-simonii K.）. The substrate was the mixture of soil, vermiculite and worm cast with six concentrations of soil Cd treatment（0 mg·kg-1, 20 mg·kg-1, 70 mg·kg-1, 150 mg·kg-1, 300 mg·kg-1 and 500 mg·kg-1）. The results showed that the lower Cd concentration（20 mg·kg-1） did not significantly inhibit the growth of either poplar, while higher concentrations（≥70 mg·kg-1） had significant inhibition effect. The bioaccumulation capacity in two poplars’ roots were higher than that of leaves and stems, and the bio-concentration factors（BCF） of grey poplars was higher than that of cathay poplars, however, their translocation factors（IF） were approximately equivalent. The contents of chlorophyll a, chlorophyll b and total chlorophyll of the leaves of two poplar seedlings were significantly lower in the Cd treatments than those of control, and the contents were negatively related to the Cd concentrations. In grey poplars, the chlorophyll a/b ratio was higher with higher Cd concentrations, though not significantly; in cathay poplars, however, such value showed a trend of increasing after decreasing, with the addition of Cd in the growth medium also caused significant deleterious effect on the net rate of photosynthesis（Pn）, transpiration rate（Ts） and stomatal conductance（Gs） in both species of poplar seedlings, but the intercellular CO2 concentration（Ci） increased dramatically, indicating that the non-stomatal factor accounted for inhibition of photosynthesis in the leaves of poplar seedlings. The ratio of Fv /Fm and Fv/F0 significantly decreased with increasing Cd concentrations in both plants. The comparison of inhibition rate of two plants indicated that grey poplars were less sensitive to the Cd stress. |
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