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根据“倒春寒”气象指标国家标准(GB/T 34816-2017),利用金衢盆地主要城市历史气象资料,整理1981—2020年“倒春寒”个例并计算得到每次“倒春寒”过程的气象指标K值。应用统计分析方法和小波分析方法,分析了金衢盆地“倒春寒”频次和强度变化特征及大气环流背景。结果表明,近40 a金衢盆地“倒春寒”发生频繁,但以轻度“倒春寒”为主,重度“倒春寒”仅占发生次数的3.4%;“倒春寒”气象指标K值在3上下波动;衢州市“倒春寒”次数和气象指标K值分别存在明显的3 a、7 a、19 a和4 a、8 a、20 a左右的年际和年代际周期变化规律;“倒春寒”较强年受贝加尔湖地区强冷空气东移南下影响,槽后冷平流不断渗透影响江南地区,导致金衢盆地气温异常下降,发生较严重“倒春寒”气象灾害。 相似文献
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气候变暖已经成为世界生态恶化的首要原因,因此,以低能耗、低排放、低污染为特征的低碳经济是目前人类应对全球气候变化,减缓温室气体排放的根本出路。农业生产与全球气候变化息息相关,低碳农业将成为今后农业发展的方向和目标。在此背景下,探索性地提出海南发展低碳高效农业的一些思考,在分析海南发展低碳高效农业的优势和制约因素的基础上,提出海南发展低碳高效农业的一些建设性的思路和建议。 相似文献
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低温胁迫对胡椒叶片生理生化及显微结构的影响 总被引:1,自引:0,他引:1
以胡椒主栽品种热引 1 号胡椒(Piper nigrum c.v. Reyin-1)和野生近缘种石南藤(Piper wallichii)为材料,经过 4 ℃低温胁迫处理,研究其在胁迫条件下植株的伤害情况、叶片解剖结构和生理生化指标变化。结果表明:低温胁迫条件下,石南藤比热引 1 号胡椒具有明显的耐寒表型,胡椒叶片厚度变化与叶片受害程度相一致;胁迫 72 h时,热引 1 号胡椒保护酶系统被破坏,石南藤则仍然表现活跃;热引 1 号胡椒的可溶性糖和可溶性蛋白含量呈现升降趋势,石南藤则维持上升;胡椒的丙二醛和脯胺酸含量与其抗寒性呈现负相关。研究结果表明,石南藤为抗寒性种质,其抗寒性比热引 1 号胡椒强,为开展胡椒抗寒育种和胡椒抗寒分子机理研究提供了材料基础。 相似文献
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Puroindolines (PINs) A and B were purified from soft (Paledor) and hard (Recital, Courtot) wheat cultivars. Their purity and heterogeneity due to post-translational processing were characterized by SDS- and acid-PAGE, reversed-phase HPLC and mass spectrometry. By using dynamic light scattering (DLS), asymmetrical flow field-flow fractionation (AF4) and size exclusion chromatography (SEC), we showed that the size distributions of PINA are similar for the three varieties and that, in solution, they self-assembled into small aggregates, mainly dimers. Conversely, PINB isolated from hard varieties (PINB-D1b and PINB-D1d) are assembled into large aggregates while PINB-D1a formed small aggregates, mainly monomers. Mixed solutions of PINA and PINB formed heteromeric aggregates. The large PINB-D1b aggregates were retained even at a high (4:1) PINA/PINB weight ratio. Reversible dissociation of large aggregates into small aggregates suggested that weak interactions control the self-assembly of PINs. The aggregative properties of PINs have now to be taken into account when studying their interactions with other components to decipher the causal relationships between these proteins and grain hardness. 相似文献