Key Laboratory of Forest Biotechnology in Yunnan, Southwest Forestry University, Kunming, Yunnan, 650224, P.R. China.
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, Guangxi University, Nanning 530004, P.R. China.
Physiol Plant. 2020 Jan;168(1):188-204. doi: 10.1111/ppl.12934. Epub 2019 Mar 4.
Bamboo is one of the fastest growing plants in the world, but their shoot buds develop very slowly. Information about the sugar storage and metabolism during the shoot growth is lacking. In the present study, we determined the activity of sucrose and starch metabolizing enzymes during the developmental period of Fargesia yunnanensis from shoot buds to the young culms that have achieved their full height. The soluble sugars and starch contents were also determined and analyzed in shoot buds and shoots at different developmental stages. The results showed that there were higher sucrose contents in shoot buds than shoots, which coincides with the sweeter taste of shoot buds. As the shoot buds sprouted out of the ground, the starch and sucrose were depleted sharply. Coupled with this, the activity of soluble acid invertase (SAI), cell wall-bound invertase (CWI), sucrose synthase at cleavage direction (SUSYC) and starch phosphorylase (STP) increased significantly in the rapidly elongating internodes. These enzymes dominated the rapid elongation of internodes. The activities of SAI, CWI, SUSYC and STP and adenosine diphosphate-glucose pyrophosphorylase were higher as compared to other enzymes in the shoot buds, but were far lower than those in the developing shoots. The slow growth of shoot buds was correlated with the low activity of these enzymes. These results complement our understanding of the physiological differences between shoot buds and elongating shoots and ascertain the physiological mechanism for the rapid growth of bamboo shoots.
竹子是世界上生长最快的植物之一，但它们的芽苞发育非常缓慢。关于芽苞生长过程中糖的储存和代谢的信息还很缺乏。在本研究中，我们测定了从芽苞到幼竹（已达到其全高）发育过程中云南箭竹的蔗糖和淀粉代谢酶的活性。还在不同发育阶段的芽苞和幼竹中测定和分析了可溶性糖和淀粉含量。结果表明，芽苞中的蔗糖含量高于幼竹，这与芽苞的甜味一致。随着芽苞破土而出，淀粉和蔗糖急剧消耗。与此相伴的是，在快速伸长的节间中，可溶性酸性转化酶（SAI）、细胞壁结合转化酶（CWI）、蔗糖合酶（SUSYC）和淀粉磷酸化酶（STP）的活性显著增加。这些酶主导了节间的快速伸长。SAI、CWI、SUSYC 和 STP 的活性以及腺苷二磷酸葡萄糖焦磷酸化酶的活性均高于芽苞中的其他酶，但远低于发育中的幼竹中的酶活性。芽苞生长缓慢与这些酶活性低有关。这些结果补充了我们对芽苞和伸长幼竹之间生理差异的理解，并确定了竹笋快速生长的生理机制。
