Correlation between rice (Oryza sativa L.) seed respiration and vigor

ABSTRACT: Seed respiration is closely related to seed vigor, but the relationship between the two remains unclear. To illustrate the above relations, we selected three varieties of rice (Oryza sativa L.) seeds with different gradients of vigor obtained by natural harvesting. The CO2 generated in the seed respiration process was monitored in real time using self-developed seed respiration detection system based on TDLAS and the vigor indexes were obtained by standard germination tests. We then analyzed the correlation between seed respiration and vigor indexes. The experimental results showed that (1) based on an assessment of five soaking times of 0 h, 12 h, 24 h, 36 h, and 48 h, the optimum soaking time was 36 h for the tested seeds; (2) the curves of rice seed respiration intensity at different harvest periods all showed an “S” shape while the respiration rate curves presented an inverted “U” shape; (3) within the 4th to the 9th hour, the correlation between the seed respiration intensity and the germination rate, germination potential, germination index of three varieties was greater than 0.71, 0.76, 0.91; 0.71, 0.63, 0.67; 0.76, 0.84, 0.73 respectively. (4) within the 3th to the 7th hour, the correlation between seed respiration rate and germination rate, germination potential, germination index of three varieties was greater than 0.73, 0.60, 0.80; 0.71, 0.74, 0.71; 0.85, 0.74, 0.81 respectively. These results indicated that respiration intensity and respiration rate can be recommended as efficient indicators for screening rice seeds with high vigor.