冰核活性细菌(INA bacteria)对杏花器官ABA、IAA和可溶性蛋白质含量的影响

试验以2个杏品种花器官为试材,研究低温及INA细菌处理下,花瓣、雄蕊及雌蕊ABA、IAA、可溶性蛋白质含量变化。结果表明:随温度下降,未接菌杏花器官内ABA和可溶性蛋白质含量呈上升趋势,-5℃是花器官的受害温度。接种INA细菌后,ABA、可溶性蛋白质含量下降,杏花器官在-3~-4℃受到伤害。接种INA细菌与对照花器官间ABA与可溶性蛋白质含量差异达显著或极显著水平。在低温及INA细菌影响下,IAA在杏花器官间无规律变化。     

冰核细菌对杏花器官抗寒性的影响

 从田间采取两个仁用杏品种的大蕾期花枝, 在室内进行水培。对花器官人工接种冰核( INA)细菌, 置于模拟自然霜夜的半导体制冷电脑控温和自动记录的人工霜箱内, 研究INA 细菌对花器官抗寒性的影响。结果表明: 杏花器官抗寒性顺序为花瓣> 雄蕊> 雌蕊。未接菌仁用杏花器官能抵抗- 4～ - 6 ℃低温, 而INA 细菌能提高仁用杏花器官相对电导率, 破坏膜保护酶SOD、POD 的活性, 使细胞积累大量自由基, 并增强膜脂过氧化作用, 加剧MDA 含量的积累, 使花器官发生严重褐变乃至死亡。INA 细菌能在- 2～ - 3 ℃诱发细胞结冰, 使组织冰点提高2 ℃左右, 因此, INA 细菌可诱发和加重霜冻害。     

INA细菌与杏花期霜冻害研究进展

综述了植物上存在的冰核细菌(INA细菌)种类与分布、影响冰核活性的成冰因素、INA细菌诱发植物霜冻机理的研究进展,重点介绍了杏INA细菌种类、活性及其年消长规律,阐述了INA细菌的存在对杏花器官组织结构、内源激素和可溶性蛋白含量的影响及INA细菌加重杏花晚霜冻害的特点,以及初步报道了应用筛选出的几种药剂在试验室内杀灭杏INA细菌及破坏冰核活性的研究结果。并对今后防御杏晚霜冻害的研究与应用进行了展望。     

黄瓜优质高效种植技术要点

<正>黄瓜是西汉时期张骞出使西域带回中原的,称为胡瓜。五胡十六国时后赵皇帝石勒忌讳"胡"字,汉臣襄国郡守樊坦将其改为"黄瓜"。1黄瓜的生长环境1.1温度黄瓜喜温暖,不耐寒冷。生育适温10～32℃。一般白天25～32℃,夜间15～18℃生长最好;最适地温20～25℃,最低为15℃左右。最适昼夜温差10～15℃。黄瓜高温35℃光合作用不良,45℃出现高温障碍,低温-2～0℃冻死,如果低温炼苗可承受3℃的低温。     

果园霜冻及防御措施

20 0 2年 4月 2 4日晚 ,山东省烟台市果树发生了自195 4年以来最严重的早春霜冻 ,直接经济损失达 5 0多亿元。为给今后搞好防冻工作提供依据 ,本文着重介绍果园霜冻为害的特点及防御措施。1　霜冻为害的特点1.1　霜冻类型　根据霜冻发生时的条件与特点不同 ,分为辐射霜冻、平流霜冻和混合霜冻。辐射霜冻延续时间较短 ,一般为几个小时 ,降温至 - 1℃～ - 2℃ ,较易预防。平流霜冻涉及范围大 ,延续时间长 ,有时可达数夜之久 ,降温剧烈 ,可达 - 3℃～ - 5℃ ,甚至可达- 10℃ ,一般防霜效果不大 ,但不同的小气候之间有很大差异。混合霜冻是上述…     

温室黄瓜优质高效种植技术

<正>1黄瓜生长条件1.1温度黄瓜喜温暖,不耐寒冷。生育适温为10～32℃。一般白天25～32℃,夜间15～18℃生长最好;最适宜地温为20～25℃,最低为15℃左右。最适宜的昼夜温差10～15℃。黄瓜高温35℃光合作用不良,45℃出现高温障碍,低温-2～0℃冻死,低温炼苗可承受3℃低温。1.2光照华南型品种对短日照较为敏感,而华北型品种对日照的长短     

苹果花期霜冻规律及预防调查

宁夏银川平原自然条件虽十分适宜苹果生长 ,但花期霜冻对苹果生产形成了一定的威胁。现将多年来我们预防苹果花期霜冻积累的一些经验介绍于下。1　苹果花期霜冻危害的一般规律苹果花期霜冻与降温幅度、低温延续时间及苹果树的物候期关系十分密切。据资料介绍 ,苹果的花蕾、花朵和初受精的幼果对低温的忍受力是逐渐减弱的。在低温持续 3 0min(分钟 )条件下 ,苹果现蕾期、花期和幼果期所能经受的低温临界期分别是 -4.0℃、-2 .3℃和-1 .7℃ ,这正是苹果中国光和金冠一般受霜冻影响小的原因。国光开花迟 ,在大多数情况下 ,霜冻发生时别的品种正…     

果树晚霜冻害的特点及预防措施

近几年来 ,早春晚霜冻害给果树生产带来严重的损失。损失程度因霜冻持续时间、温度下降幅度、冻结转到解冻的急剧程度及果树所处的物候期等情况不同而有差异。现将晚霜冻害的特点及预防措施总结如下 ,供参考。1　晚霜冻的发生特点与危害特征1.1　发生特点　根据霜冻发生时的条件与特点不同 ,霜冻可分为 3种类型 :①辐射霜冻。这种霜冻延续的时间短 ,一般只是早晨几个小时 ,使局部果园气温下降到- 1℃～ - 2℃ ,因持续时间短 ,危害较小 ,较易预防。②平流霜冻。由强大寒流侵袭从而导致果园温度降至- 3℃～ - 7℃ ,甚至可达 - 10℃。这种霜冻…     

夏菜早熟栽培低温危害的表现及防护

夏菜大多为喜温蔬菜 ,易受低温危害 ,特别是大棚反季节早熟栽培的夏菜 ,低温危害发生更为频繁。1　夏菜对温度的要求早熟栽培夏菜的主要品种有番茄、茄子、黄瓜、蒲瓜等 ,均为喜温性蔬菜。生长适温为 2 0～ 30℃ ,15℃以下生长缓慢 ,10℃生长停止 ,代谢失调 ,易得病 ,5℃以下易受冷害 ,地温低于 10℃ ,根系生长不良 ,易发沤根。 4种夏菜中 ,黄瓜对温度要求最高 ,也最易受冻 ,其它依次为蒲瓜、茄子、番茄。温室黄瓜15℃以下就可能受害 ,黄瓜地温低于 12℃就易发沤根。2　低温危害的类型2 .1　冷害　冷害是指在作物生长期内 ,温度降低到作物当…     

果树晚霜冻害调查及预防补救措施

2004年4月23日山东胶东地区发生霜冻后,笔者在招远、栖霞、莱州、蓬莱、牟平、海阳和平度等地作了大量调查,会同气象部门和有关专家,分析总结霜冻发生规律,提出预防和补救意见,以供专业人员和果农在生产中参考。1霜冻情况调查1.1降温时间和幅度受南下冷空气影响,2004年4月23日晚上8点到24日凌晨6点,胶东烟台范围内发生了仅次于“2002年4月25日”的低温霜冻。全市多数果园普遍遭受冻害。低温持续8～10个小时。本次寒流冷气,来势迅猛,气温由白天中午的21℃下降到晚上的-2～-4℃,降幅超过20℃。1.2冻害类型本次冻害为平流霜冻 辐射霜冻,二者混…     

冰核细菌对仁用杏胚珠超微结构的影响

 应用透射电镜对两个仁用杏品种‘白玉扁’和‘一窝蜂’接种冰核细菌并低温处理后的胚珠超微结构进行了观察, 发现冰核细菌对胚珠的超微结构有一定影响: (1) 使珠心细胞发生严重的质壁分离,细胞质中存在大量泡状结构, 线粒体的内部结构完全被破坏, 呈透明状, 而且有些珠心细胞中形成同心圆状的多膜内含物; (2) 使胚囊中卵细胞的细胞核外膜膨胀, 甚至核膜局部解体, 细胞质中细胞器减少。这些变化致使胚珠发育不正常, 影响受精而导致减产或绝收。接种冰核细菌并低温处理比单纯低温处理对胚珠超微结构的破坏程度重。     

杏花器官组织抗寒性研究

通过人工模拟霜害试验,研究了杏花抗寒性与花器官组织结构的关系,并统计了冻害率。结果表明:4个仁用杏品种的抗寒性由强到弱为优一、白玉扁、一窝蜂、龙王帽;在同一朵花中,抗寒性强弱为花瓣>雄蕊>雌蕊;未接种冰核细菌的花比接菌的抗寒性强。-3℃低温处理后,各品种的子房显微结构均受到不同程度的破坏。     

高温胁迫下水杨酸对黄瓜幼苗生理特性的影响

以"吉利4号"黄瓜为试材,研究高温胁迫下水杨酸对黄瓜幼苗生理特性的影响。结果表明:不同浓度的SA溶液均可降低黄瓜叶片中的相对电导率、丙二醛含量,提高黄瓜幼苗叶片中叶绿素、游离脯氨酸含量,增强根系活力;表明水杨酸能够缓解高温胁迫对黄瓜幼苗的伤害,其中以250 mg/L处理效果最好。     

Pre-harvest application of 2, 6-dichloroisonicotinic acid, -aminobutyric acid or benzothiadiazole to control post-harvest storage diseases of melons by inducing systemic acquired resistance (SAR)

Summary

Field-grown rockmelon plants were treated with -aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA), benzothiadiazole (BTH) or water during fruit development and evaluated for increased resistance against plant diseases or post-harvest pathogens. One experiment was conducted at Camden, NSW, Australia (INA, BABA or water). Two experiments were at Griffith, NSW, Australia (INA, BTH or water). Growing plants and harvested fruits were assessed for disease symptoms from natural infections and assayed for the accumulation of chitinase and peroxidase, two major pathogenesis-related (PR) proteins induced as a result of systemic acquired resistance (SAR). Harvested fruit from both BTH- or INA-treated plants showed a significant (P < 0.05) reduction in the severity and incidence of post-harvest storage diseases mainly caused by Fusarium, Alternaria and Rhizopus. However, there were no differences in disease severity and the incidence of rots between using four fortnightly foliar sprays of INA or BTH during flowering and fruit development, or a single spray of BTH, 2 weeks before harvest. Each approach showed an equivalent reduction in storage diseases. Plants treated with BABA showed less resistance against powdery mildew in the field and storage rots from natural inoculum, and lower increases in chitinase and peroxidase activities than those treated with INA. In all trials, an additional post-harvest dip with guazatine [0.05% (w/v)] gave a substantial reduction in melon storage rots. Pre-harvest application of INA or BTH reduced the occurrence of powdery mildew and downy mildew on the leaves. Over the three field-experiments, INA had a small phytotoxic effect causing lesion-like symptoms on leaves and affected plant growth, but not yield, at Camden, when applied during flowering and 2 weeks after flowering. However, INA did not produce any phytotoxic effects in the two experiments at Griffith when applied serially, four times to plants after flowering.     

外源H2S对低温下日光温室黄瓜光合作用及抗氧化系统的影响

为了探讨外源硫化氢（H2S）对黄瓜耐冷性的调控机理,以‘津优3号’黄瓜为试材,叶面喷施H2S供体硫氢化钠（NaHS）,以清水处理为对照,研究H2S对温度变化的响应,以及对黄瓜叶片光合作用和抗氧化系统的影响。结果表明：随着日光温室内气温降低和低温持续时间的延长,黄瓜叶片的H2S含量及D–/L–半胱氨酸脱巯基酶（CDes）活性先升高,后降低;光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、核酮糖–1,5–二磷酸羧化酶（RuBPCase）活性,以及暗下光系统Ⅱ最大光化学效率（Fv/Fm）、光下实际光化学效率（ΦPSII）、电子传递效率（ETR）和光化学猝灭（qP）逐渐降低,胞间CO2浓度（Ci）、初始荧光（Fo）和非光化学猝灭（NPQ）趋于升高。低温胁迫可使MDA含量增加,超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性先升高后降低。与对照相比,NaHS处理叶片的H2S含量和CDes活性及Pn、Gs、Tr、RuBPCase活性、Fv/Fm、ΦPSII、ETR和qP明显升高,Ci、Fo和NPQ显著降低。低温下NaHS处理的MDA含量显著低于对照,而SOD、POD、CAT、APX和GR活性明显高于对照。NaHS处理的黄瓜产量比对照增加15.3%。可见CDes催化合成H2S受低温胁迫诱导,外源H2S可增强活性氧清除能力,减轻低温对黄瓜叶片光合机构的伤害。     

Cu2+, Zn2+和Mn2+对冷胁迫下嫁接黄瓜幼苗叶片提取液SOD活性的影响

以自根和嫁接黄瓜幼苗为试材,研究叶片Mn、Cu、Zn和Fe含量及低温胁迫下SOD活性的差异,结果表明:嫁接黄瓜叶片Mn、Cu和Zn的含量均显著高于自根黄瓜,而Fe的含量则显著低于自根黄瓜;低温胁迫第3天,嫁接黄瓜叶片SOD、Cu/Zn-SOD和Mn-SOD活性均显著高于自根黄瓜,Fe-SOD则显著低于自根黄瓜。为探索嫁接黄瓜叶片高含量Mn、Cu、Zn与SOD活性之间的关系,向低温胁迫第3天的自根黄瓜叶片SOD提取液中加入Mn2 、Cu2 和Zn2 ,使之与嫁接黄瓜叶片SOD提取液对应组合的Mn2 、Cu2 和Zn2 浓度相等,研究此时的SOD及其同工酶活性的变化,结果发现:Mn2 、Cu2 和Zn2 加入自根黄瓜叶片提取液后均能显著增强SOD活性,其增强作用的大小依次为Mn2 Zn2 ,Mn2 Cu2 ,Mn2 ,Cu2 ,Cu2 Zn2 Mn2 ,Cu2 Zn2 和Zn2 。3种离子的加入都不影响Fe-SOD的活性。这一结果说明黄瓜叶片Mn、Cu和Zn的含量是影响SOD活性大小的重要因素,嫁接黄瓜吸收Mn、Cu和Zn的能力较强是其SOD活性显著高于自根黄瓜的重要原因之一。     

Inhibition of powdery mildew development and activation of antioxidant enzymes by induction of oxidative stress with foliar application of a mixture of riboflavin and methionine in cucumber

Powdery mildew (Sphaerotheca fuliginea Pollacci) infection in cucumber was significantly reduced by foliar application of a mixture of riboflavin and methionine (RM). The effects of fungicidal activity on leaves applied with RM were detected through restriction of progress of colonies and disease severity compared with control plants. The initial response to foliar application of RM was abrupt generation of hydrogen peroxide in the leaves of cucumber plants. Activities of antioxidant enzymes such as SOD and POD were abruptly increased by foliar application of RM. However, activities of antioxidant enzymes in control plants were increased with disease development 9 d after pathogen inoculation. Cucumber leaves have six major SOD isoforms. When plants were foliar-applied with RM, densities of three SOD isozyme bands at SOD-1, SOD-2, and SOD-3 were increased 3 d after foliar application. Leaves of cucumber plants have three major POD isozyme bands. Densities of three POD isozyme bands were increased 3 d after foliar application with RM. Four major PPO isozyme bands were determined in cucumber leaves. Though the overall banding patterns of PPO in control and RM-applied plants were similar, the band profiles in leaves applied with RM were characterized by high densities of the three major isoforms. Activities of PPO in leaves applied with RM increased rapidly during the 3 d after foliar application, and then remained relatively constant for 15 d. Although activities of PPO in the leaves of control plants also abruptly increased after 9 d, it was lower than those of RM-applied plants during the whole time. The difference in lignin content between control and RM-applied plants was detected 9 d after foliar application; it was high in leaves applied with RM.