ISSN:
1573-5036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Pea plants (Pisum sativum L.) were cultivated for 42 days in well stirred Richter's nutrient solution maintained (±5%) at concentrations 1, 0.1, 0.01 and 0.001. Data are given for the N, P and K contents of the plants sampled at different times, in terms of mg/g dry matter and µg-atoms per plant; also for the absorption rate of these elements in µg-atoms per g fresh weight of roots per day (IM) and their utilization in dry-matter production. In the most dilute nutrient solution, during the first phases of growth, elimination of N occurred, to a lesser extent also of P and least of all of K. The same order was found in the ratio of the internal plant concentration (fresh-weight basis) to that of the external medium. Maximum yields were obtained with the 1.0 solution concentration when the plants contained 10 times more N, 11 times more P and 14 times more K than those grown in the most dilute solutions. The distribution of elements varied with the treatment; in general the content in the tops as a percentage of the total content changed most in the case of N corresponding to the most intensive loss of this element into the medium. Plant uptake of elements was not proportional to their concentration in the culture medium; increasing the latter from 0.001 to 0.01 increased uptake 5 to 10 times, from 0.01 to 0.1, twice to 5 times and from 0.1 to 1.0, only about twice. As the concentration of the solution increased, the utilization of N, P and K (dry-matter production per unit element content) decreased. Maximum growth was characterized by a certain relative absorption rate (IM), ranging from 5 to 14 µg-atoms P, 20 to 107 µg-atoms N and 31 to 35 µg-atoms K per g fresh weight roots per day, during the period of cultivation. The ratio between the relative growth rate (RGR) and relative absorption rate (IM) for maximum growth of peas ranged in the case of P from 4.0 during the first phases of growth to 1.0 at the time of ripening of the pods; the corresponding ratios for N and K were respectively, 1.10 and 0.135 and 0.73 and 0.40. Higher ratios indicate an insufficient nutrient supply, lower values either an abundant supply or a depressing effect of the solution on growth.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01372880
Permalink