【作者】 张艳洁；

【导师】 赵琦；

【作者基本信息】 首都师范大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 古树生长年代久远,出现了不同程度的衰老症状。随着古树的衰老,其养分、水分、矿质营养元素、激素和酶系统等都有显著变化。本实验从古树生理生化特征及叶绿体结构与功能等方面比较了古树和幼树的差别,并选择和确定了可作为古树衰老标记的生理指标。①通过显微观察银杏和国槐的叶绿体超微结构,发现古银杏叶片的叶绿体呈梭形,随树龄增长,叶绿体排列有相对疏松的趋势,叶绿体数目相对减少;国槐叶绿体呈椭球形,贴壁排列,百年国槐较对照国槐叶片细胞排列疏松。②通过超微结构观察,随季节变化,银杏叶绿体中淀粉粒的数量及体积均呈上升趋势,树龄越大,上升程度越大;国槐叶绿体中淀粉粒数量及体积也有同样趋势。在同一生长时间,古树叶绿体内淀粉粒的数量及体积均比对照明显增加,增加程度与树龄成正比,古树的叶绿体基粒片层数量与清晰度呈下降趋势,树龄越大叶绿体基粒片层数量越稀疏且片层模糊。③古树叶绿素含量测定结果显示,不同树龄的树木叶绿素含量均在8月达到当年生长季节的最高值,当年5月和10月叶绿素含量较低;而对照树相同月叶绿素含量均比古树高。④通过叶绿素荧光测定对古、幼树的光合特性进行研究。荧光动力学参数揭示出古树的光合速率较低,树龄越大,光合速率越低;在最适条件下经过暗适应后的Fv/Fm值揭示出古银杏、古国槐明显受到胁迫,受抑制程度与树龄成正比;qP值揭示出古树的光合活性较对照低,光合活性大小与树龄成反比,树龄越大光合活性越小;qN值揭示出古银杏更适于接受强光照射。⑤通过太赫兹(THz)时域图,发现THz透过率与树龄成反比,水分蒸发量也与树龄成反比,树龄越大银杏叶片水分的蒸发速率越低。⑥应用气-质联用仪测定了不同树龄的银杏和国槐的脱落酸和生长素含量,结果显示,脱落酸的含量与树龄成正相关,树龄越大脱落酸含量越高。同一株树,脱落酸的含量与生长季节成正相关;在同一生长月份,生长素的含量与树龄成反比关系,树龄越大生长素含量越低。⑦基于以上生理方面特性表征古树与幼树的差异,推测在分子基因水平上可能会有差异,因此通过选取与光合作用相关的rbcL基因,进行序列对比,发现不同年龄的的基因碱基突变位点差异性较明显,说明rbcL基因序列可作为银杏衰老的特性表征之一。可能是由于国槐古幼树树龄差距小,国槐rbcL基因序列的差异性较小,国槐古幼树在分子水平上差异不明显。更多还原

【Abstract】 Old tree is became aging gradually with the passage of time.As old trees aging, nutrition,water,hormone and enzyme show obvious changes.Physiological structure,biochemical index and molecular marker were compared between young trees and old trees in this experiment,in order to select indicator to characterized aging.①Leaf ultrastructure of Ginkgo biloba and Sophora japonica were observed through light microscopy,the results showed that cells of Ginkgo biloba leaf were regular shape,shape of chloroplast was spindle,the arrangement of leaf cells became loose and the quantity of chloroplast decreased with the passage of time.Cells of Sophorajaponica leaf were ellipse,shape of chloroplast was ellipse,the arrangement of centennial Sophora japonica leaf cells were more loose than contrast.②Leaves of Ginkgo biloba and Sophora japonica were collected in different seasons to observe through electron microscopy.The results showed that quantity and volume of starch of old Ginkgo biloba and Sophora japonica increased with time, compared control.The change of quantity and definition of chloroplast of old and control trees showed declined trend.The quantity and volume of starch of old trees were more than contrast and proportional to the age in the same time.③The change of chlorophyll content of old and contrast trees were determined, the results showed that the chlorophyll content of old and contrast trees reached the highest point in May,the chlorophyll content of contrast was more than old tree in every month.④The photosynthetic activity of old and young trees were studied,through determined chlorophyll fluorescence.Fluorescence kinetic parameters showed that photosynthetic rate was higher than old trees,the value of Fv/Fm showed that photosynthetic rate of old trees decreased,degree was proportional to the age,the value of qP showed that photosynthetic activity of old trees was lower than contrsat, degree was inversely proportional to the age,the value of qN showed that old Ginkgo biloba were more adaptive to intense light.⑤Transmittance of THz and Moisture evaporation was inversely proportional to the age,through THz-TDS.⑥ABA and IAA were determined through Gas - MS.The results showed that the content of ABA was proportional to the age in same month,the content of ABA of the same tree was proportional to the time,the content of IAA was inversely proportional to the age in same month.⑦rbcL gene was choose to be sequences alignment.The results showed that the difference of bases mutant between different trees were obvious,because this,the rbcL gene could be a marker to characterize Ginkgo biloba aging.The difference of bases mutant between old and young Sophora japonica were less evident,partly because the age distance between old and young was small.更多还原