酸铝胁迫下常绿杨根冠超微结构变化

中国的亚热带地区气候温暖湿润、雨量充沛，是中国速生丰产林基地，森林土壤多呈偏酸性和酸性，为富铝化酸性土壤，容易造成植物铝毒害。A-61/186（Populus×enramericana cv.）是澳大利亚 L．D．Pryor 博士选育的半常绿杨树无性系（semi-evergreen poplar clone），母本为美国南方种的落叶型美洲黑杨（Populus deltoids Marsh），父本为原产智利的常绿品种欧洲杨智利变种（Populus nigra cv.Chile），是中国林科院郑世锴研究员于1987年从巴基斯坦引入中国的3个常绿杨品系之一，适合热带亚热带种植。以常绿杨A-61/186（Populus×euramericana cv.）根冠细胞为材料，采用水培酸铝胁迫实验，在胁迫30 d、60 d和90 d时在透射电子显微镜下进行根冠细胞超微结构的观察及拍片，研究在酸铝胁迫下浓度和作用时间对其超微结构的影响，探究铝毒条件下杨树根冠细胞的超微结构变化，并为根冠细胞铝毒亚显微水平评价提供资料。结果表明，随着铝浓度的升高，根冠细胞壁溶解断裂；细胞基质由凝胶态向分散碎块转变；淀粉粒数量有减少的趋向，淀粉质体数量有增加的趋向，而淀粉粒堆重心偏向由明显到不明显的趋向。随着铝作用时间的延长，根冠细胞在60 d浓度0.370 mmol·L^-1淀粉粒急剧减少；在90 d浓度0.666 mmol·L^-1淀粉粒质体急剧减少；淀粉粒堆或淀粉质体堆无重心偏向。

Acid and Aluminum Stress on Root Cap Ultrastructure of Evergreen Poplar Clone

The climate of China’s subtropical area is warm humid, abundant rainfall, is fast-grown forest base. Forest soil is partial acidic or acidic, rich in aluminum. Which easily cause aluminum poisoning for the plant.A-61/186 （Populus×euramericana CV.） is the semi-evergreen poplar clone cultivated by Australian doctor L.D.Pryor, which female parent is Populus deltoids Marsh from the southern United States, and the male parent is originated Populus nigra CV. of Chile. It is one of three evergreen poplar clones and suitable for tropical and subtropical areas were introduced from Pakistan in 1987 by Mr. Shikai Zheng, who is a researcher of state forestry administration P.R.China. The changs in Ultrastructure of root cap cells were studied under controlled concentration and acting time by evergreen poplar clone A-61/186 （Populus euramericana CV.）, using hydroponic experiment acid aluminum stress. Root cap cell ultrastructure were observed and shooting under the transmission electron microscopein in 30 d, 60 d and 90 d. Acid concentration and acted time under aluminum stress on its ultrastructure were explored. Used for revealing changes of poplar root cap cells ultrastructure under aluminum toxicity, then for aluminum toxicity submicroscopic level evaluation of root cap cells. The results showed that cellwall was dissolved and brokend with the increasing of stress concentration, and Al content 3 was obvious . Cell matrix changed from gel state to Scattered debris. Starch grain declined in the number and amyloplasts increased in the number. While the core deviation of starch grain heap were changed from non-clear to clear trend. With the development of acting time, Starch grain were sharply reduced in Al content 2 under 60 d stresse and amyloplasts in Al conten 3 under 90 d stress. The core of starch grain heap was not deviated obviously.