Detailed Explanation of the Biological Characteristics of Angelica sinensis (Part Three)

(1) Bolting and flowering. Angelica sinensis is a monocarpic plant. Under normal cultivation conditions, it enters the bolting and flowering stage in the third year. About half a month after the plant turns green again, the growing point begins to shift from the vegetative growth state to the reproductive growth state, forming a reproductive growing point, and some protrusions gradually appear at its apex, namely the inflorescence primordia. As the inflorescence primordia elongate and grow, the tip of each primordium begins to widen and produces several small protrusions, namely the umbellule primordia. After the umbellule primordia elongate, they form the rudiment of a compound umbel. At the same time, the basal stem swells and lengthens, forming internodes and constituting the rudiment of the stem. After the umbellule primordia elongate and their tips widen, some small protrusions are produced at their apex, namely the flower primordia, which successively develop into calyx, petals, stamens and pistils, forming flowers. At this time, the stem nodes begin to enter the elongation stage, the internodes grow rapidly and extend above the ground, entering the bolting stage. It flowers from June to July and sets fruit from July to August.

(2) Fertilization process. The stamens of Angelica sinensis consist of two parts: the filament and the anther. When the stamens develop to a certain stage, the pollen sacs inside the anthers produce many pollen grains, and when the pollen grains mature, sperm are produced inside them. The pistil consists of three parts: the stigma, the style and the ovary. The ovary is inferior, 2-locular, with ovules inside. When the ovary and anthers mature, flowering begins. At this time, the filaments elongate rapidly, the anthers extend out of the flowers and release pollen grains. A small portion of them falls on the stigma of the same flower, resulting in self-pollination, while another portion falls on other florets of the same plant or different plants, resulting in cross-pollination. June to July is the peak period of flowering and pollination.

During the flowering and fertilization process, Angelica sinensis requires clear and slightly windy weather, and the relative atmospheric humidity is required to be around 70-80%. Too high a temperature or too low a humidity will cause physiological drought of the stamens and pistils and loss of fertilization ability, thereby reducing the seed-setting rate. In addition, rain during flowering easily causes pollen grains to absorb too much water and rupture or to enter the ground with rainwater, which also affects fertilization and reduces the seed-setting rate.

(3) Fruit formation and maturation. After flowering and pollination of Angelica sinensis, the fertilized ovules develop into seeds, while ovules with poor fertilization or insufficient nutrition shrink into shriveled grains. Subsequently, dry matter in the seeds of Angelica sinensis begins to accumulate in large amounts. By mid-to-late August, the fruits mature and form broad ovate schizocarps.