The symptoms of boron deficiency in rapeseed vary greatly depending on the degree of boron deficiency. In severe cases, the seedlings are atrophied and die, and light individuals show signs of disease after flowering. The roots of the diseased plants are stunted. The fibrous roots are not long, the epidermis turns brown, some root and neck enlarge, and the cortex cracks. The leaves become dark green at first, the leaf shape becomes smaller, the leaf mass becomes thicker, becomes more brittle, the leaf ends are rewinded, and the leaf is not flat. Then, the edge of the lower middle leaf begins to turn purple, and then develops to the interior, and then turns into a blue-purple; the veins and its nearby tissues turn yellow, resulting in the formation of blue and purple patches. The last part of the leaf margins died, and the entire leaf turned yellow and fell off earlier. After the convulsions, the growing point atrophies or dies. The stolons are cracked. The transmission system and fertilization are destroyed. Carbohydrates are trapped in the leaves. The flowering is slow, the inflorescences are shortened, the small branches are clustered and the flowers are not strong (commonly called "flowers but not real"). Or the grains are not full, and when ripe, the pods are short as radish horns. The epidermis of the keratinocytes and culms becomes purple-red or blue-purple, longitudinal slits appear in the lower cortex of the stem, and cracks appear in the upper part.
Prevention and remedial measures: Boron-poor soil, 0.5 to 1 kg of borax per acre applied as basal fertilizer for site preparation. The transplanted seedlings were transplanted with boron prior to transplantation. Borneol or 0.1% to 0.2% borax was sprayed on rape seedlings, before bolting, before flowering, or when boron deficiency was found in plants.
Prevention and remedial measures: Boron-poor soil, 0.5 to 1 kg of borax per acre applied as basal fertilizer for site preparation. The transplanted seedlings were transplanted with boron prior to transplantation. Borneol or 0.1% to 0.2% borax was sprayed on rape seedlings, before bolting, before flowering, or when boron deficiency was found in plants.