桃需冷量遗传特性的研究

对桃的９个杂交组合４６３株杂种实生苗需冷量进行测定,统计结果表明：桃需冷量是由多基因控制的,Ｆ＿１需冷量平均值较亲中值短,不同组合偏离程度不同,南山甜桃、红日、玛丽维拉、白凤、大久保需冷量育种值分别为１５９、２１６、３１９、８３１、８３４ｈ,遗传传递力分别为７９%、５４%、９２%、８３%、９３%。需冷量的遗传力为８９．６９%。萌芽开花与需冷量密切相关。     

葡萄品种需冷量及打破休眠研究

对上海地区葡萄促成栽培的几个主要品种的休眠需冷量进行了调查,发现在供试的5个品种中以里扎马特的需冷量最低,自然条件下仅为447.5h;其次为京亚和巨峰,需冷量均低于1000h;绯红和无核白鸡心需冷量最高,均超过1000h。由此推算,上海地区葡萄结束自然休眠的时间在1月上旬至2月中旬。打破休眠的试验表明以20%石灰氮12月中旬处理效果最佳。     

橡胶树低温伤害的生理反应

在人工零上低温下,巴西橡胶树(Hevea brasiliensis)叶质膜透性随低温处理时间的延长而持续上升,抗冷品系的上升速率比不抗冷品系慢。呼吸强度和ATP含量均随处理时间的延长而持续下降,抗冷品系下降速率比不抗冷品系慢。叶绿体Mg~(++)—ATPase活性也表现出明显抗性差异。可见,低温下叶组织的质膜透性、呼吸强度、ATP含量以及Mg~(++)—ATPase活性的变化与品系抗冷性有关。低温下呼吸强度、ATP含量与质膜透性变化呈负相关,质膜透性的变化与供能有关。     

亚硫酸氢钠处理减轻低温对温州蜜柑光合作用的影响

 低温胁迫使温州蜜柑叶片的净光合速率(Pn)、光系统Ⅱ的光化学效率(Fv/Fm)及光合电子传递速率(ETR)下降，反映跨膜质子动力势的叶绿素毫秒延迟发光(ms-DIE)减弱，叶片中的ATP含量降低。低温胁迫前，用NaHSO₃ 5 mmol/L涂于叶片表面，可使处理植株叶片的Pn和Fv/Fm分别少下降了11.5%和11.6%，ETR和ATP含量几乎没有下降，ms-DLE的下降幅度减少。可见，在柑橘上施用NaHSO₃能够减轻短期低温对光合机构及光合作用的影响。     

桃品种需冷量评价模式的探讨

 通过1986～2001年对450余份桃品种需冷量的7．2℃模式、0～7．2℃模式(不包括0℃)和犹它模式比较分析，归纳出桃品种需冷量的评价模式为：以秋季日平均温度稳定低于7．2~C的日期为需冷量测定的起点，以0～7．2℃累积低温值作为需冷量的评价标准比较适宜；犹它模式在中需冷量和长需冷量范围内能有效预测休眠的结束，而不适宜低需冷量品种的测定；7．2℃模式不适宜作为需冷量的评价模式。品种的需冷量与叶芽开放和始花期的相关系数分别为0．52和0．58，均达到极显著水平。提出了桃品种需冷量评价的系列标准参照品种。     

影响湖南早稻生产的五月低温的风险评估

五月低温是影响湖南双季早稻的一种常见的低温冷害。近年来,五月低温发生频率较大,影响早稻生产,对粮食安全生产造成威胁。本文根据湖南省96个气象站1961-2009年5月逐日气象资料和湖南省《气象灾害术语和分级》地方标准,系统分析了五月低温的地域分布特征和发生时段的分布规律。并根据低温对水稻影响的原理,综合考虑低温发生的不同时段和低温程度对冷积温的意义,改进了冷积温计算方法,创建了当量冷积温。同时利用五月低温强度指数,结合湖南早稻种植实际情况,定量评估了基于早稻种植现状的五月低温的生产风险。结果表明：湘北和湘中地区发生五月低温的气象风险较高,且是早稻种植主产区,早稻生产的低温风险较大,是防范重点区域;湘南等地早稻五月低温气象风险小,仅在五月低温发生较重的年份须注意防范;湘西虽是五月低温气象风险的高发区,但由于该区域双季早稻种植面积小,低温对早稻生产影响不大。最后提出了各区域双季早稻生产安排防灾避灾的建议。     

Ca^2＋,BR对玉米呼吸器官耐冷性的影响

研究了外源Ｃａ２＋、ＢＲ对低温下玉米胚芽呼吸速率、膜透性以及对线粒体呼吸控制比、ＳＯＤ活性和ＭＤＡ含量的影响。结果表明，Ｃａ２＋、ＢＲ处理，相应提高了种苗胚芽的呼吸速率，降低膜透性。低温下经Ｃａ２＋、ＢＲ处理的玉米种苗，其线粒体有较高的呼吸控制比。Ｃａ２＋处理的线粒体中ＳＯＤ活性比对照高；ＭＤＡ含量比对照低。Ｃａ２＋和ＢＲ可能是在低温下通过维持膜系统的正常结构和功能来提高玉米种苗的耐冷性的     

Auswirkungen des Klimawandels auf die Verfügbarkeit von Kältewirkung (Chilling) für Obstgehölze in Deutschland

To quantify the effects of climate change on fruit production in Germany, this study aimed at determining long-term trends in winter chill, as calculated with the Chilling Hours and Dynamic Models (Chill Portions). An idealized daily temperature curve was used to convert daily temperature records from 43 weather stations, taken throughout the twentieth and late nineteenth centuries, into an hourly dataset, which was then converted to units of winter chill. Besides exposing temporal trends in winter chill, the data could be spatially interpolated, yielding contiguous maps of typical winter chill in Germany around 2010, as well as chilling losses since 1950. Throughout Germany, winter chill varied between 1700 and 3000 Chilling Hours or 125 and 150 Chill Portions. The areas of highest winter chill were located in the northern parts of the country. For the whole of Germany, there were no significant temporal trends. The extent of interregional variation in winter chill depended on the chilling model used. While the Chilling Hours Model showed strong declines in winter chill for the areas around Dresden and Leipzig, as well as for the Lake Constance region, the Dynamic Model did not detect such dramatic changes. More than a decline in winter chill, increased heat during the winter months might become a challenge to German fruit growers. As already experienced during the extraordinarily warm winter of 2006/07, warm temperatures during the winter can cause fruit trees that fulfill their chilling requirements relatively early to bloom prematurely. This can then lead to elevated risk of frost damage and hamper the homogeneity of flowering.     

Polyamines enhance chilling tolerance of cucumber (Cucumis sativus L.) through modulating antioxidative system

Cucumber chilling-resistant cultivar Changchun mici and -sensitive cultivar Beijing jietou were used in this study to investigate the effects of exogenous PAs on protection against chilling injury as well as on changes of physiological features, and the fluctuation of free PAs content in the leaves under chilling stress. Upon chilling treatment, free spermidine (Spd), spermine (Spm) and putrescine (Put) were remarkably induced in the leaves of cv. Changchun mici 1 day after treatment. The induction of Put declined thereafter, whereas Spd and Spm levels increased steadily. In the leaves of cv. Beijing jietou, Put content was increased only at 1 day after chilling while Spd content decreased significantly upon chilling treatment. Chilling reduced soluble protein content, and decreased the activities of antioxidant enzymes, including superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) only in Beijing jietou. However, these changes could be renovated by exogenous application of Put and Spd. It was also found that pretreatment with Put and Spd diminished the increased electrolyte leakage and malondialdehyde (MDA) content caused by chilling in the leaves of both cultivars. Pretreatment of methyglyoxal-bis-(guanylhydrazone) (MGBG), the PAs biosynthetic inhibitor cancelled the effects of PAs in most of the treatments. Moreover, histochemical staining and quantitative measurements showed that exogenous application of Put and Spd eliminated but MGBG exaggerated the hydrogen peroxide (H₂O₂) accumulation caused by chilling stress, especially in leaves of Beijing jietou. Interestingly, Changchun mici was found to contain higher endogenous free PAs contents compared to Beijing jietou. While no significant difference of SOD, POD and CAT activities was found between non-chilling Changchun mici and Beijing jietou seedlings, the former exhibited higher APX activity than the latter. These results suggest that PAs play important roles in the tolerance of cucumber against chilling stress, which is most likely achieved by acting as oxidative machinery against chilling injury.     

二苯胺处理对鸭梨果实冷害的影响

研究了贮前二苯胺（DPA）处理对在低温条件下（0℃）贮藏鸭梨果实的果心褐变及生理变化的影响。结果表明：急骤降温（0℃）可产生严重的早期果心褐变,贮前二苯胺处理在一定条件下可减轻鸭梨果实的早期褐变,贮藏60 d时DPA处理果实的褐变指数为0.233,而对照为0.417;同时DPA处理可降低果实的乙烯释放量、抑制多酚氧化酶活性、保持果实酚类物质含量,对丙二醛（MDA）含量和果实相对电导率也有一定影响。