Effect of phosphorus (P) nutrition and leaf age on physiological growth parameters in a P-inefficient potato genotype

Abstract

SUMMARYA pot experiment was conducted in a controlled environment growth chamber to investigate the effect of phosphorus (P) nutrition on the physiological growth parameters of old and young leaves in a potato genotype with inefficient P utilisation. The genotype (CGN 18233) was grown under three P regimes (10, 20, and 30 µM; rated low P, medium P, and high P, respectively). The treatments were arranged in a randomised complete block design, with three replications. The results showed that plant dry matter (DM) yield and relative growth rate (RGR) increased with increasing P. The different P treatments did not affect P concentrations and electron transport rates in young leaves, or the photosynthetic rate per unit leaf area, chlorophyll fluorescence yields, starch contents, total soluble sugar (TSS) contents, or SPAD values (chlorophyll content) of young and old leaves. Leaf age affected both leaf P concentration and electron transport rate, but chlorophyll fluorescence, SPAD values (chlorophyll content), the photosynthetic rate per unit leaf area, starch contents, and TSS contents did not differ significantly between young and old leaves. Thus, parameters such as leaf P concentration and electron transport rate need to be determined separately for young and old leaves in such studies, while measurements of parameters such as chlorophyll fluorescence, SPAD value (chlorophyll content), photosynthetic rate per unit leaf area, and starch and TSS contents need not be made separately on young and old leaves.