Effect of Nutrient Solution Concentration at the Heading Time on the Growth, Development, and Seed Storage Protein Content of Rice Plants in a Controlled Environment

Abstract

Genetically modified (GM) rice varieties that store up pharmaceutical proteins in seeds have recently been developed. Since the pharmaceutical protein-encoding genes of these varieties are connected with the promoter of seed storage protein-encoding genes, the pharmaceutical protein content increases as the seed protein content increases. Rice varieties were grown in hydroponic culture at different nutrient solution concentrations at the heading time in a controlled environment. Emergence of non-productive stems was inhibited through an early reduction in the nutrient solution concentration due to accelerated translocation from the leaf blade, leaf sheath, and stem to the seed. Further, the seed storage protein composition was altered by regulating the concentration of the nutrient solution. When the nutrient solution concentration was increased just before heading occurred, translocation to the seeds as well as the generation of non-productive stems decreased. The total protein concentration of rice seeds was not increased by the treatments of nutrient solution concentration, however, it was greater in the plants grown in the present study than in plants grown in field cultivation. Seeds in which high concentrations of total protein and seed storage protein accumulate can be produced when the nutritional content is kept constant in hydroponic culture.