Lichtenthaler H K, Abuslima E, Nick P
Botanical Institute, Molecular Biology and Biochemistry of Plants, Karlsruhe Institute of Technology (KIT), D-76133 Karlsruhe, Germany.
Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology (KIT), D-76133 Karlsruhe, Germany.
Photosynthetica. 2023 Jun 1;61(3):297-307. doi: 10.32615/ps.2023.020. eCollection 2023.
A 50-year-old solitary, sun-exposed ginkgo tree had strongly been pruned in the fall of 2021. Very few buds for the formation of new leaves, twigs, and branches were left over. In spring 2022, these few remaining buds responded with the formation of a different leaf type. These leaves were 2.7 times larger and also thicker than in the years before. In addition, the mean content of total chlorophylls [Chl (+)] per leaf area unit of dark-green leaves was 1.45, those of green leaves two times higher as compared to the years before pruning and the two other ginkgo trees which had been investigated in parallel. A comparable increase was also found for the level of total carotenoids (+). The mean content for Chl (+) were 1,118 mg m for dark-green and 898 mg m for green leaves as compared to 435 to 770 mg m in leaves of other trees. The higher values for Chl (+) and total carotenoid content showed up also on a fresh and dry mass basis. Thus, with the formation of a new, larger leaf type by changes in morphology (leaf size and thickness) and the increase of photosynthetic pigments, the pruned ginkgo tree was able to compensate for the much lower number of leaves and photosynthetic units.
一棵50岁的、暴露在阳光下的孤零零的银杏树在2021年秋天被大幅修剪。留下用于形成新叶、嫩枝和树枝的芽非常少。2022年春天，这些剩余的少数芽长出了不同类型的叶子。这些叶子比之前几年的叶子大2.7倍，也更厚。此外，深绿色叶子每单位叶面积的总叶绿素含量[Chl(+)]平均为1.45，绿色叶子的这一含量比修剪前几年以及同时调查的另外两棵银杏树高出两倍。总类胡萝卜素(+)水平也有类似的增加。深绿色叶子的Chl(+)平均含量为1118毫克/平方米，绿色叶子为898毫克/平方米，而其他树木叶子的含量为435至770毫克/平方米。基于鲜重和干重，Chl(+)和总类胡萝卜素含量的较高值也很明显。因此，通过形态变化（叶片大小和厚度）形成新的、更大的叶片类型以及光合色素的增加，被修剪的银杏树能够弥补叶片和光合单位数量的大幅减少。
