• Journal of Photoscience
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• 제5권2호
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• pp.53-61
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• 1998

Using a squash plant, a chilling-sensitive species, and a spinach plant, a chilling-resistant one, effects of chilling temperature on the photosynthetic machinery were studied in terms of chlorophyll fluorescence. When thylakoid membranes were isolated and subjected to incubation at different temperatures, spinach showed stable photosystem II activity at the low temperature side, in contrast to squash which showed quite severe inactivation at low temperature. When parameters of chlorophyll fluorescence were examined, chilling in darkness did not affect either Fv/Fm or photochemical and non-photochemical quenching, in both types of plants. However, chilling of squash plants under irradiance of medium intensity caused a specific decrease in Fv/Fm accompanied by a decline in energy-dependent quenching. Contrastingly, photosystem li of spinach plants were not much affected by light-chilling. When the pool size of zeaxanthin was examined after exposure to high light at different temperatures, squash plants was shown to have a much lower content of antheraxanthin + zeaxanthin, as compared to spinach plants, during low-temperature photoinhibition. These results suggest that chilling-sensitive plants have low capacity to dissipate excitation energy nonradiatively, when they are exposed to low-temperature photoinhibition, and, as a consequence, more vulnerable to photoinhibitory, damage to the photosynthetic apparatus.

• 한국균학회지
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• 제18권4호
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• pp.203-208
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• 1990

고추 역병균(疫病菌) 유성세대(有性世代)인 난포자(卵胞子)는 원형(円形)이며 막(膜)이 두텁고 크기는 $24.4\;{\mu}m$$(20{\sim}32.5{\mu}m)$ 이며 장난기(藏卵器)는 $26.7\;{\mu}m$$(21{\sim}37.5{\mu}m)$이고 장정기(藏精器)는 도우낫모양으로 크기는 $6.5{\times}4\;{\mu}m(6{\sim}8{\times}5{\sim}6\;{\mu}m)$이었다. 난포자(卵胞子)의 형성단계(形成段階)는 접종(接種) 직후(直後) 각(各) 배우자형(配偶者型)의 균사(菌絲)가 신전(伸展)되어 접촉(接觸)되고 확장기(擴張期)로 이어지면서 완숙난포자(完熟卵胞子)로 되기까지 사단계(四段階)로 구분(區分)되었다. 난포자(卵胞子) 형성(形成)에 최적온도(最適溫度)는 $20{\sim}24^{\circ}C$이었고 온도(溫度)가 $25^{\circ}C$ 이상되면 오히려 감소(減少)하는 경향(傾向)이었다. 새로운 호박배지는 기존(旣存) V-8 한천배지(寒天培地)보다 많은 난포자(卵胞子) 형성(形成)을 보였으나 고추잎배지(培地)에서는 난포자(卵胞子)가 형성(形成)되지 않았다. $1800{\pm}300$ 및 $800{\pm}300$ Lux의 주야(晝夜) 광조사(光照射)는 암조건(暗條件)보다 오히려 난포자(卵胞子) 형성(形成)에 저해적(沮害的)이었다.