Transport direction of photosynthates in Cymbidium sinense at different growth and development stages

This is actually a question of changes in the "sink" and "source" relationship; at different growth and development stages, the growth center is different. 1. Leaf bud growth stage: during this period, the young leaf bud is the primary growth center. Not only are its own photosynthetic assimilates not exported, but it also strongly attracts the photosynthetic assimilates of other leaves for transport to it. A portion of the assimilates from mature leaves is also transported to the roots, mainly concentrated in the root tips. 2. Vegetative growth stage: both the roots and the first-year leaves are metabolic centers, with the former slightly stronger than the latter. This period is mainly the assimilate storage stage, preparing for reproductive growth. 3. Flower bud growth stage: the photosynthetic assimilates of each leaf are transported only to the flower bud, indicating that this is the only growth center among the reproductive organs during this period. 4. Capsule growth stage: at this stage, leaf assimilates are mainly transported to the capsule, but a portion is also transported to the roots. The assimilates transported to the roots and pseudobulbs are mainly stored in the form of starch grains. (Ye Qingsheng, Pan Ruichi)