The water-saving potential of using micro-sprinkling irrigation for winter wheat production on the North China Plain

The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain. Water-saving technologies and procedures are thus urgently required. To determine the water-saving potential of using micro-sprinkling irrigation(MSI) for winter wheat production, field experiments were conducted from 2012 to 2015. Compared to traditional flooding irrigation(TFI), micro-sprinkling thrice with 90 mm water(MSI1) and micro-sprinkling four times with 120 mm water(MSI2) increased the water use efficiency by 22.5 and 16.2%, respectively, while reducing evapotranspiration by 17.6 and 10.8%. Regardless of the rainfall pattern, MSI(i.e., MSI1 or MSI2) either stabilized or significantly increased the grain yield, while reducing irrigation water volumes by 20–40%, compared to TFI. Applying the same volumes of irrigation water, MSI(i.e., MSI3, micro-sprinkling five times with 150 mm water) increased the grain yield and water use efficiency of winter wheat by 4.6 and 11.7%, respectively, compared to TFI. Because MSI could supply irrigation water more frequently in smaller amounts each time, it reduced soil layer compaction, and may have also resulted in a soil water deficit that promoted the spread of roots into the deep soil layer, which is beneficial to photosynthetic production in the critical period. In conclusion, MSI1 or MSI2 either stabilized or significantly increased grain yield while reducing irrigation water volumes by 20–40% compared to TFI, and should provide water-saving technological support in winter wheat production for smallholders on the North China Plain.     

糖对椰枣组织培养物的影响

【目的】为降低椰枣愈伤组织褐化率和提高体胚发生率,研究培养基中不同糖处理对愈伤组织和体胚发生的影响,为优化培养基配方提供依据。【方法】以椰枣组织培养物为研究对象,进行3种糖处理（蔗糖、蔗糖+果糖、蔗糖+葡萄糖）的组织培养试验,统计椰枣愈伤组织褐化率及体胚发生率,测定不同糖处理下愈伤组织、体胚和不定芽的淀粉、蔗糖、果糖、葡萄糖含量,综合分析不同糖处理对椰枣组织培养物影响的差异。【结果】在蔗糖培养基中增加果糖,体胚和不定芽的蔗糖含量和葡萄糖含量下降,愈伤组织和体胚的果糖含量及愈伤组织的淀粉含量上升,愈伤组织褐化率升高。在蔗糖培养基中增加葡萄糖,不定芽蔗糖含量和愈伤组织果糖含量降低,愈伤、体胚和不定芽的淀粉含量上升,愈伤和体胚的葡萄糖含量上升,体胚发生率升高。愈伤组织和体胚的淀粉和果糖含量显著高于不定芽的淀粉和果糖含量（P<0.05,下同）,愈伤组织的葡萄糖含量显著高于体胚和不定芽,体胚的蔗糖含量显著高于不定芽,不定芽的蔗糖含量显著高于愈伤组织。相关分析结果表明:愈伤组织褐化率与愈伤组织果糖含量、不定芽果糖含量均呈显著正相关;体胚发生率与体胚淀粉含量呈显著正相关;体胚发生率与体胚蔗糖含量、愈伤组织褐化率与愈伤组织果糖含量均呈极显著正相关（P<0.01,下同）;体胚发生率与体胚蔗糖含量、愈伤组织葡萄糖含量、体胚葡萄糖含量均呈极显著正相关,同时,与体胚淀粉含量呈显著正相关。【结论】在椰枣愈伤组织诱导与增殖培养过程中减少果糖的用量,在体胚发生培养时增加葡萄糖的用量,可降低愈伤组织的褐化率,提高体胚发生率。     

The Metabolic Responses of Aspergillus flavus to N-Acetylcysteine, Ascorbate, and H2O2

Aflatoxin, the secondary metabolite of Aspergillus flavus and A. parasiticus, is the most toxic product in nature. In this study, N-acetylcysteine （NAC）, ascorbate, and H2O2 were used to ascertain their effects on fungal metabolic response of A. flavus. The results demonstrated that NAC did not affect fungal growth, but inhibited the aflatoxin Bt production, with the concomitant sporulation reduction. NAC increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG）, but decreased the activity of glutathione reductase （GR）. Ascorbate had similar effect on fungal growth, sporulation, and GR activity, but GSH/GSSG and total glutathione （tGSH, including GSH and GSSG） were significantly increased. H2O2 at high concentration （5 mM） inhibited fungal growth, but the aflatoxin production was increased. At the same time, it reduced GR activity and enhanced tGSH. Though reductive agents had different effects on GSH metabolism, reductive conditions inhibited aflatoxin production and sporulation without any effect on fungal growth. The results in this report confirmed that the relationship between oxidative stress and aflatoxin production is theoretically important in controlling aflatoxin contamination.     

甘蓝型油菜MYB28转录因子对根肿菌和水杨酸的响应特征

MYB转录因子参与植物的生长发育和逆境胁迫过程,在植物防御相关信号反应中起着重要的调控作用。 为了明确MYB28在油菜与根肿菌互作中的作用,对感病甘蓝型油菜中双11中MYB28家族基因在根肿菌接种以及 水杨酸处理后的表达模式进行了分析。不同组织表达模式分析显示,相比于根和叶,BnaMYB28 在茎和种子中的表 达水平更高;BnaMYB28 基因在根肿菌和外源水杨酸处理下均有不同程度的表达响应,外源水杨酸处理下Bna⁃ MYB28-1 和BnaMYB28-3 上调表达,BnaMYB28-2 表达则受抑制。根肿菌侵染后,BnaMYB28-1 在整个侵染期表达 量均显著上调,但在加入水杨酸后表达被显著抑制;BnaMYB28-3 表达量在接菌后7 d和28 d显著上调,在关键皮层 侵染期（接菌后14 d）表达量与对照组相比没有变化,但在施加水杨酸处理后表达量显著上调。综上,外源水杨酸能 正向调控BnaMYB28-1 和BnaMYB28-3 表达,BnaMYB28-3 可能通过水杨酸信号路径参与油菜与根肿菌的互作。     

芝麻黄化突变体YL1的叶片解剖学及光合特性

表型性状标记在作物遗传育种中具有重要的应用价值。在芝麻地方种质"庙前芝麻"中发现了能够稳定遗传的黄化突变体YL1,对该突变体的叶片解剖特征、光合特性及农艺性状的比较分析表明,突变体YL1黄化心叶和平展叶在各个发育时期的叶绿体结构均与同时期野生型存在明显差异,下表皮气孔保卫细胞数是正常叶的2倍左右。YL1的叶绿素a、总叶绿素、类胡萝卜素含量均只有同时期正常含量的30%~40%,叶绿素b含量只有正常叶的20%;光合速率在初花期及以前均显著低于同期正常叶,但到终花期与正常叶相当;YL1的生育期和初花期显著推迟,株高和单株蒴果数明显降低,每蒴粒数和千粒重略微降低。显微观察表明,YL1的叶绿体形态结构发育不规则,基粒和基粒片层数目明显少于野生型,使得叶绿素含量过低,属于叶绿体发育异常导致的叶绿素缺少型突变体。     

氮钾肥施用技术对芝麻养分积累、产量和品质的影响

研究了氮钾肥用量和施用方法对芝麻养分积累、产量和品质的影响。结果表明,试验条件下,芝麻最高产量施肥量为N 155.8 kg/hm2、K2O 111.4 kg/hm2;氮肥深施和肥料分次施用有利于提高肥料利用率;芝麻粗脂肪含量与粗蛋白质含量存在负相关,施用钾肥芝麻粗蛋白质含量可提高0.61%～2.39%,粗脂肪含量降低0.47%～0.76%,施用氮肥均有提高芝麻粗脂肪含量和粗蛋白质含量的趋势;氮和磷主要存在于芝麻子粒中,钾主要存在于果壳和茎秆中,硼主要存在于茎秆中;在芝麻产量830.8～2 064.1 kg/hm2条件下,芝麻共带走氮35.0～94.2 kg/hm2、磷7.6～19.8 kg/hm2、钾40.9～133.8 kg/hm2、硼57.5～119.5 g/hm2;每生产100 kg芝麻子粒,芝麻共带走氮3.9～5.4 kg、磷0.8～1.1 kg、钾4.1～7.4 kg、硼4.3～6.9 g。     

湖北省花生平衡施肥技术研究Ⅴ.花生养分积累分配规律

分析了花生的养分积累及分配变化规律。结果表明,花生总干物质量、养分积累量除钙、镁在荚果膨大期最大外其余均随生育进程而增加,至收获期达到最大。每生产100 kg荚果,花生带走氮3.63 kg,磷0.47kg,钾1.45 kg,钙0.90 kg,镁1.00 kg,铁1.38 kg,铜0.02 kg,锌0.26 kg,硼0.05 kg。开花下针期是花生养分积累的关键时期。开花下针期后,花生除钙、镁外的营养元素主要从叶片和茎向荚果逐渐转移,根系分配变化较小。