Effects of soil moisture content on the growth and physiological status of ginger (Zingiber officinale Roscoe)

Abstract

Ginger (Zingiber officinale Roscoe), one of the most valuable economic plants from the Zingiberaceae family, is used worldwide as a spice and flavoring agent in the beverage, bakery, confectionary, and pharmaceutical industries. Soil moisture is one of the most important constraints in ginger cultivation. In the present paper, the phenotype, physiology, biochemistry, and expression difference of genes coding for key enzyme for endogenous hormone metabolism in ginger under different soil moisture conditions (water-filled pore space, WFPS) were measured. Our results indicated that with the increase of soil moisture content, the ramet number of Z. officinale gradually increased, and the ramet number increased to 26.7 ± 3.7 at 40% humidity. However, the stem height, stem diameter, and the relative chlorophyll content were highest at 25% humidity. Similarly, the activities of superoxide dismutase (SOD) and peroxidase (POD) as well as the contents of abscisic acid (ABA) and ethylene (Eth) content remained relatively low at 25% humidity, whereas they were relatively high at lower moisture (10%) and higher moisture (30–40%) levels. In addition, the expression patterns of key enzyme-coding genes involved in ABA synthesis and Eth metabolism were analyzed to elucidate the effect of soil moisture on ginger cultivation. The results showed that the expression of the genes were in accordance with the variation of ABA and Eth under different soil moisture levels. In sum, soil moisture significantly affects the growth of Z. officinale, and 25% soil humidity is suitable for the growth of Z. officinale.