Varietal difference in stomatal aperture in rice seedlings in relation to the cool temperature susceptibility in Tongil group varieties

• Published in: Japanese Journal of Crop Science Vol. 56; no. 4; pp. 482 - 490
• Main Authors: Nishiyama, I. (Agricultural Research Center, Tsukuba, Ibaraki (Japan)), Lee, M.H, Yun, Y.D
• Format: Journal Article
• Language: Japanese; English
• Published: CROP SCIENCE SOCIETY OF JAPAN 1987
• Subjects: ARROZ IRRIGADO; COLD; ESTOMA; FRIO; FROID; GENETIC VARIATION; IRRIGATED RICE; MOUVEMENT; MOVEMENT; MOVIMIENTO; PLANTULAS; PLANTULE; PROPIEDADES TERMICAS; PROPRIETE THERMIQUE; RIZ IRRIGUE; SEEDLINGS; STOMATA; STOMATE; THERMAL PROPERTIES; VARIACION GENETICA; VARIATION GENETIQUE; VARIEDADES; VARIETE; VARIETIES
• ISSN: 0011-1848; 1349-0990
• DOI: 10.1626/jcs.56.482

The varietal difference of stomatal aperture in rice seedlings was studied in the phytotron, in relation to the cool temperature susceptibility of Tongil group (an indica-japonica hybrid group) varieties. Eight varieties including 4 japonica and 4 Tongil group were used. They were Sangpungbyeo (cool temperature tolerant), Daecheongbyeo (medium), Odaebyeo (medium) and Hwasongbyeo (medium) as japonica type, and Suwon 339 (moderately susceptible), Iri 377 (moderately susceptible), Samgangbyeo (susceptible) and Yongmunbyeo (susceptible) as Tongil group. The seedlings were grown in a natural light room of the phytotron upto the early hardening stage. The temperature treatments were started at the middle hardening stage (approximately 2-leaf stage) in the artificially lit room, under about 30, 000 lux illumination (0700-1900 hours) and at about 60 percent relative humidity. The set temperatures were (1) 20°C, (2) 16°C, (3)20°C → 16°C from the 6th day, (4) 20°C → l2°C from the 8th day and (5) 16°C → 12°C from the 8th day. Several fAactors affecting the estimation of stomatal aperture of rice seedlings in the artificially lit room were examined (Tables 1-4, Figs. 1 and 2). The following results were obtained in relation to the varietal difference of stomatal aperture in rice seedlings : (1) Stomatal aperture was larger in the Tongil group varieties than in the japonica type, and varietal difference was observed also within the japonica type or the Tongil group varieties (Tables 1-6 and Figs. 3-6). (2) More tolerant varieties of cool temperature generally showed smaller stomatal aperture, except Daecheongbyeo which showed particularly small aperture (Figs. 3-6). (3) Stomatal aperture decreased at lower temperature, and the degree of decrease was smaller in the Tongil group varieties (Figs. 3 and 4). Accordingly, the varietal diffecrence was larger at lower temperature. (4) Preliminary experiments showed that reactions in the stomatal aperture to the temperature shift from 20°C to 16°C, 20°C to 12°C and 16°C to 12°C were all different (Figs. 5 and 6). (5) Stomatal aperture showed a diurnal change, higher in the afternoon, in the experimental condition in the artificially lit room (Figs. 3 and 4). These results implies that stomatal aperture has a high reciprocal correlation with the cool temperature tolerance of rice seedlings, and that thus the estimation of stomatal aperture would contribute to the elucidation of physiological mechanism of cool temperature tolerance in rice seedlings.