[Absorption and allocation of nitrogen, phosphorus, potassium in Prunella vulgaris and their relationship to dry matter accumulation].

OBJECTIVE

The accumulation of dry matter, nitrogen, phosphorus and potassium in Prunella vulgaris and their relationships under field condition were studied, in order to provide a basis for the rational fertilization.

METHODS

Through the dynamic sampling of P. vulgaris in different growing stages, and the dry weight of plant, the amount of dry matter and the content of N, P and K within each organ of the plant were measured.

RESULTS

The dry weight of P. vulgaris linearly increased with the increase of nitrogen, phosphorus and potassium accumulation, there existed a significant correlation at whole growth period. The maximum stage accumulation rate of dry matter from mid-April to the beginning of May, reached 63.71%. The amount of dry matter was mainly distribution in leaves from late March to mid-April. The distribution ratio in stem was the highest from beginning of May to late May. Until mid-June, the distribution ratio of dry matter in spicas was higher than that in other organs. The absorption amounts of N, P and K were lower before mid-April, and the nutrient element was concentrated in plant leaves. From late April to beginning of May, the N, P and K accumulation reached maximum of total absorptive capacity, which accounted for 72.35%, 59.82%, 87.41%, respectively, and the mineral elements were concentrated distribution of plant stems. When transferred to reproductive stage, both accumulation amount and distribution rate of nutrient elements in spicas increased rapidly, which reached the maximum until mid-June. From elongation stages to quaring period was the period of maximal accumulation of dry matter and showed the maximal efficiency of N, P and K nutrition.

CONCLUSIONS

The time from elongation stages to quaring period is the most crucial period in the growth development stage of P. vulgaris, and should be paid more attention to the supply of mineral nutrition and moisture of plant to promote spicas formation and dry matter accumulation in this stage. The average N, P2O5 and K2O absorption amount per 100 kg dry matter of spicas were 1.62, 0.36, 2.88 kg respectively, and the ratio of N-P2O5,-K2O was 1 : 0.22: 1.77.