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排序方式: 共有478条查询结果,搜索用时 859 毫秒
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于雾凉季测定了叶片叶绿素荧光参数,探讨了4~6 ℃夜间低温对4种相对光强下生长的两种西双版纳沟谷雨林树苗光系统Ⅱ(PSⅡ)活性的影响及雾对植物的可能保护机制。随夜间低温处理时间延长,不同光强下生长的团花树(Anthocephalus chinensis)和玉蕊(Barringtonia macrostachya)叶片日间和长期光抑制,以及PSⅡ反应中心的可逆失活或破坏加剧,生长环境光越强夜间低温的效应越明显,弱光下其效应不显著。间接表明雾使光强减弱利于缓解自然夜温降低对本区热带植物的影响。中光强下玉蕊对照植株发生了胁迫诱导的光抑制;相同处理条件下玉蕊的光抑制程度均比团花树重,表明玉蕊对夜间低温引起的光抑制更敏感。夜间低温处理后,中等和低光强下团花树的热耗散多于玉蕊,表明其光保护作用较强。夜间低温处理期间两种植物的光抑制与热耗散增多和PSⅡ反应中心的可逆失活或破坏的加剧有关。 相似文献
63.
Maize (Zea mays ssp. mays) and eastern gamagrass (Tripsacum dactyloides) are known for their susceptibility to chilling injuries. Their hybrid (Z. mays × T. dactyloides) showed higher tolerance to low temperatures (–2 °C) in the field than its parents. Exposure to 5 °C for 2 or 3 d reduced the variable to maximal chlorophyll fluorescence ratio (FV/FM), an indicator of the maximum photochemical efficiency of the photosystem 2, and the variable to minimal fluorescence ratio (FV/F0) more in maize and eastern gamagrass than in hybrid plants. Chlorophyll contents for rewarming plants (25 °C for 3 d) were lower than before chilling in both parents while values for hybrid plants were similar. Electrolyte leakage was higher in chilled than control plants but it did not show significant differences among genotypes. Our data suggest that hybrid plants have higher capacity to recover from chilling injury in controlled conditions than their parents. 相似文献
64.
冷胁迫诱导、咖啡因抑制的水稻根新基因片段的分离及表达分析 总被引:2,自引:0,他引:2
利用差异显示(Differential display)及H.Y-Yellow琼脂糖凝胶分离等方法,从冷胁迫和甘露醇共同处理的冷敏感水稻(Wase toitsu)根的总RNA中,分离出冷胁迫诱导的cDNA片段,经过测序和同源比较,发现它是一尚未报道的新基因片段。这一基因的表达对温度具有敏感的反应特性,4℃时表达水平明显增加,在正常温度(25℃)下,其表达水平又可快速降低。当幼苗根用0.5mol/L甘露醇预处理2h后,转入冷胁迫,其低温诱导的表达水平增加更为明显。在甘露醇预处理之前加入咖啡因处理根1h,其表达水平明显降低,几乎与正常温度下的对照相同。据此推测,这一基因可能参与了冷胁迫或水分胁迫诱导的耐冷过程中咖啡因敏感信号的传导。
相似文献
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René R Balandrán-Quintana Ana Ma Mendoza-Wilson Gerardo Alvarez-Manilla Carl W Bergmann Irasema Vargas-Arispuro Miguel Angel Martínez-Téllez 《Biochemical and biophysical research communications》2002,290(1):577-584
The effect of pectic oligomers (OG) on ethylene biosynthesis, electrolyte leakage (EL), and CO(2) production was studied in discs excised from zucchini fruit (Cucurbita pepo L.) and stored at 20 or 2.5 degrees C. At 20 degrees C, OG enhanced ethylene biosynthesis and had a transient effect on decreasing EL, but showed little effect on respiratory rate; both the amount and size of the oligomer were important in changing both ethylene synthesis and EL. At 2.5 degrees C, OG increased both ethylene biosynthesis and respiratory rate with a maximum effect at 100 microg of oligomer and peaking at 6 h; shorter oligomers demonstrated an even greater effect on ethylene biosynthesis, but differences were smaller in respiratory rate. EL at 2.5 degrees C was affected most by 1 microg of OG and by monomeric galacturonic acid, with transient increases that peaked at 8 h. We suggest a signaling role for OG in the early steps of cold acclimation or chilling injury. 相似文献
68.
Ca2+-CaM对过氧化氢诱导玉米幼苗耐冷性的影响 总被引:6,自引:1,他引:5
H2O2预处理可提高玉米幼苗的耐冷性及其体内钙调素(CaM)活性。阻断胞内Ca2 库的动员(钌红处理)、降低细胞中Ca2 水平(EGTA处理)及抑制CaM活性(TFP和CPZ处理)均可完全消除H2O2诱导的玉米幼苗的耐冷性。阻止胞外Ca2 跨膜进入胞内(La3 处理)并不抑制、甚至还能轻微地提高H2O2诱导的耐冷性。高Ca2 (20mmol.L^-1)处理削弱H2O2诱导的耐冷性。这些结果表明,CaM及胞内Ca2 库在H2O2诱导的玉米幼苗耐冷性的形成过程中起重要作用,而质外体中高浓度Ca2 和跨膜进入胞内会削弱H2O2诱导的耐冷性。 相似文献
69.
Chickpea is the third major cool season grain legume crop in the world after dry bean and field pea. Chilling and freezing range temperatures in many of its production regions adversely affect chickpea production. This review provides a comprehensive account of the current information regarding the tolerance of chickpea to freezing and chilling range temperatures. The effect of freezing and chilling at the major phenological stages of chickpea growth are discussed, and its ability for acclimation and winter hardiness is reviewed. Response mechanisms to chilling and freezing are considered at the molecular, cellular, whole plant, and canopy levels. The genetics of tolerance to freezing in chickpea are outlined. Sources of resistance to both freezing and chilling from within the cultivated and wild Cicer genepools are compared and novel breeding technologies for the improvement of tolerance in chickpea are suggested. We also suggest future research be directed toward understanding the mechanisms involved in cold tolerance of chickpea at the physiological, biochemical, and molecular level. Further screening of both the cultivated and wild Cicer species is required in order to identify superior sources of tolerance, especially to chilling at the reproductive stages. 相似文献
70.
TOYOMI KOTAKI 《Physiological Entomology》1998,23(1):53-61
Abstract. Diapause adults of Plautia stali Scott maintained at 20°C under short day conditions (LD 12:12 h) were exposed to four temperatures of 5–20°C to examine the effect on diapause development which was assessed in terms of oviposition. Diapause adults kept at 20°C under short day conditions changed their body colour gradually from brown to green and started egg laying after a prolonged preoviposition period. Those transferred to either 10 or 15°C also showed colour change but did not lay eggs. Bugs exposed to 5°C underwent neither body colour change nor oviposition and died more rapidly than those kept at higher temperatures. When 30-day-old diapause adults were chilled at 5, 10 or 15°C for 30 or 60 days and returned to 20°C and long day conditions (LD 16:8 h), the preoviposition period varied primarily depending on the chilling, but not on the temperature. On the other hand, when 60day-old diapause adults chilled for 30 days were observed at 20°C and long day conditions, their preoviposition period tended to be longer as the chilling temperature was lower In this case, a temperature of 10°C appeared to intensify diapause. Therefore, the effect of chilling on diapause development varied depending on the age at which insects were chilled. When chilled bugs were transferred to short day conditions at 20°C, most females failed to lay any eggs and some turned green, then after a while, some green bugs changed to brown again. These results indicate that bugs remained sensitive to short day conditions even after a 60-day chilling at 10 or 15°C. 相似文献