Abstract
Decrease in the grain yield resulted from a low percentage of opened spikelets under high temperature (HT) during anthesis is a serious problem in the seed production of photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) lines, and the mechanism is little understood. Elucidating the physiological mechanism underlying the effect of HT during anthesis on spikelet-opening of PTGMS lines would have great significance in exploring the effective way to mitigate the adverse effect of HT. In this study, two PTGMS lines and one restorer line of rice were used and were subjected to normal temperature (NT) and HT treatments. The results showed that, compared with NT, HT significantly decreased the percentage of opened spikelets, fertilization percentage and seed-setting by significantly increasing the percentage of wrapped spikelets and reducing the spikelet-opening angle, length of spikelet-opening time. The HT significantly decreased the contents of soluble sugars, jasmonic acid (JA) and methyl jasmonate (MeJA) in the lodicules before and at glume-opening, which were significantly correlated with and accounts for the low percentage of opened spikelets under HT for rice, especially for the PTGMS lines.
Highlights
Decrease in the grain yield resulted from a low percentage of opened spikelets under high temperature (HT) during anthesis is a serious problem in the seed production of photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) lines, and the mechanism is little understood
HT markedly enhanced spikelet-opening and increased the number of opened spikelets on the first day from the treatment, when compared with normal temperature (NT), and the increase in opened spikelets was more for the two PTGMS lines (Peiai 64S, 32.08%, Shen 08S, 38.74%) than for the restore line (Yangdao 6, 16.24%, Fig. 1A–C)
HT decreased the number of opened spikelets of both PTGMS lines on the second day from the treatment, the peak of spikelet-opening of the PTGMS lines under HT appeared earlier than under NT (Fig. 1D,E)
Summary
Decrease in the grain yield resulted from a low percentage of opened spikelets under high temperature (HT) during anthesis is a serious problem in the seed production of photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) lines, and the mechanism is little understood. Starch, jasmonic acid (JA), methyl jasmonate (MeJA) and water content of the lodicules have been proposed to be closely associated with the spikelet-opening in rice, the above physiological traits and their relationships with the spikelet-opening and fertilization percentage were observed Such a study would provide insight into the process in the spikelet-opening under HT during anthesis and explore the effective way to alleviate the damage of HT to PTGMS rice lines
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