砧木年龄对美国山核桃嫁接苗光合特性的影响

为研究砧木年龄与嫁接苗生长的关系,笔者对3年生、5年生和9年生美国山核桃砧木嫁接苗的新梢生长特征进行分析,并比较了它们新梢叶片叶绿素含量及荧光、光合特性的差异。结果表明:不同年龄美国山核桃砧木嫁接苗新梢平均长度和粗度均是9年生>5年生>3年生; 砧木年龄越大,其嫁接苗新梢叶片的净光合速率、叶绿素含量、水分利用效率越高,蒸腾速率越小。试验结果说明砧木年龄越大,嫁接苗的光合能力及抗旱能力越强。

Effects of rootstocks ages on the shoot growth and leaf photosynthetic fluorescence characteristics of pecan seedling

The ‘Pawnee' pecan cuttings were grafted onto rootstocks which were 3-year-old, 5-year-old and 9-year-old respectively. The growth, chlorophyll contents, capabilities of fluorescence and photosynthetic characteristics of the new shoots were measured. The results showed that the average length and diameter of the grafted seedling at the end of the first growth season were influenced by the ages of rootstocks. The shoot length and diameter of seedlings grafted with 9-year-old rootstock was the highest. The grafts with older rootstock possessed the higher net photosynthetic rate, total chlorophyll content, water use efficiency and lower transpiration rate in new shoot leaves. This study indicated that the grafted seedlings with older rootstocks had advantages over the ability of photosynthesis, water consumption regulation and drought adaptation.