J Integr Plant Biol. ›› 1957, Vol. 6 ›› Issue (3): -.

• Research Articles •    

Fertilizers in Relation to the Growth and Development of Crop Plants. V. On the Relative Growth in Wheat Plant

Yan Yü-rui, Pao Wen-kwei   

Abstract: 1. The growth of roots, shoots, and grains of wheat plant as measured by dry matter accumulation followed all closely the well known S-shaped growth curve . In the growing period of 180 days, about one half of the total dry matter in roots were accumulated within a period of 30 days arround the time of shooting. From shooting to blooming, a period of 75 days, nearly 70% of dry matter of the shoots were accumulated. The accumulation of dry matter in grains was exceedingly rapid. From heading to ripening, within 37 days, grains gained 41% of the total dry matter of the shoots. While in this same period of time, the shoots only gained 10-17% of dry matter. It becomes apparent therefore that at least 58%–75% of dry matter in grains was transferred from the material accumulated in leaves and stems before the time of heading. 2. In the tillering stage of wheat plant, the curve of relative growth rate between root and shoot ((root/shoot) × 100 against the age of plant) as measured by dry matter accumulation goes down to a minimum, then rises rapidly during the end of tillering stage and reaches to a maximum at the time of shooting (about 90–105 days from the time of sowing under the natural condition of Chengtu), after this, the curve drops down rapidly as the plant going to maturation . 3. The more the application rate of fertilizers (NPK) used the lower will be the relative growth rate between root and shoot . However, when the dry weight of root was considered alone with the application rate of fertilizers, the data showed that a maximum root growth was tained for the variety 2419 with an application rate of 2.5 kg of NPK per mow and for the variety Chengtu-beardless, 5 kg. These application rates of fertilizers ware considered, therefore, as the optimum rates used before sowing. While for the shoots, the more the application rate of fertilizers used, the more will be the accumulation of dry matter. 4. Application of fertilizers (NK) at the beginning of shooting would result in lowering the dry matter accumulation in roots. While for the shoots, on the contrary, fertilization at that time would stimulate the accumulation of dry matter greatly. Thus, the relative growth rate between root and shoot would be lowered significantly by ferfilization at that time. 5. It is surprising to mention that the ratio between grain and shoot would be the minimum when the application rate of fertilizers before sowing was optimum . However, the ratio would be raised efficiently by the application of additional fertilizers (NK) at the beginning of shooting. Therefore, in order to secure good yield, proper fertilization practice should involve optimum application rates of fertilizers both before sowing and at the time of shooting. 6. About 15 days after the beginning of shooting the root growth as measured by dry matter would reach the maximum value, and afterward, practically no increment of dry matter in root could be detected. In order to avoid the draw back effect on root growth by additional application of fertilizers at shooting stage, it would therefore be wise to apply the fertilizers a little later than the beginning of shooting.

Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn
Copyright © 2022 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q