The drought response of landraces of wheat from the northern Negev Desert in Israel

Summary Diverse landraces of wheat, collected from the semi-arid (150 to 250 mm of total annual rainfall) Northern Negev desert in Israel were considered as a potential genetic resource of drought resistance for wheat breeding. These materials were therefore evaluated for their reponses to drought stress in agronomical and physiological terms. Up to 68 landraces, comprising of Triticum durum, T. aestivum, and T. compactum were tested in two field drought environments, in one favourable field environment, under post-anthesis chemical plant desiccation which revealed the capacity for grain filling from mobilized stem reserves, under a controlled drought stress in a rainout shelter and in the growth chamber under polyethylene glycol (PEG)-induced water stress. Biomass, grain yield and its components, harvest index, plant phenology, canopy temperatures, kernel weight loss by chemical plant desiccation, growth reduction by PEG-induced drought stress and osmotic adjustment were evaluated in the various experiments.Landraces varied significantly for all parameters of drought response as measured in the different experiments, which was in accordance to their documented large morphological diversity. Variation in grain yield among landraces under an increasing drought stress after tillering was largely affected by spike number per unit area. Kernel weight contributed very little to yield variation among landraces under stress, probably because these tall (average of 131 cm) landraces generally excelled in their capacity to support kernel growth by stem reserve mobilization under stress. Yield under stress was reduced with a longer growth duration of landraces only under early planting but not under late planting. Landraces were generally late flowering but they were still considered well adapted phenologically to their native region where they were always planted late.Landraces differed significantly in canopy temperature under drought stress. Canopy temperature under stress in the rainout shelter was negatively correlated across landraces with grain yield (r=0.67^**) and biomass (r=0.64^**) under stress. Canopy temperature under stress in the rainout shelter was also positively correlated across landraces (r=0.50^**) with canopy temperature in one stress field environment. Osmotic adjustment in PEG-stressed plants was negatively correlated (r=–0.60^**) with percent growth reduction by PEG-induced water stress. It was not correlated with yield under stress in any of the experiments. In terms of yield under stress, canopy temperatures and stem reserve utilization for grain filling, the most drought resistant landrace was the Juljuli population of T.durum.     

巴厘菠萝果实发育期间香气成分的变化

采用顶空固相微萃取技术,研究巴厘菠萝果实发育过程中香气成分的组成及变化。结果表明,巴厘菠萝果实发育过程中共检测出48种成分,主要为酯类、烯烃,其中辛酸甲酯、己酸乙酯、辛酸乙酯等成分是菠萝果实的重要香气成分,是菠萝成熟果实的特征香气。巴厘菠萝在果实发育不同阶段,各香气成分的相对含量变化较大。     

半高丛越橘果实香气成分的GC—MS分析

采用静态顶空和气相色谱—质谱联用技术,以半高丛越橘品种北陆、圣云和北蓝为材料,研究了半高丛越橘果实香气成分。结果表明,半高丛越橘以醇类、酯类、萜类和酮类物质为主。共检测出39种挥发性成分,其中北陆检测出16种,圣云17种,北蓝23种。2-甲基丁酸乙酯和β-芳樟醇是半高丛越橘的特征香气,构成了半高丛越橘特有的香气,同时乙酸丁酯、2-丁酮、D-柠檬酸为北陆的特征香气,丁酸乙酯、2-丁酮为圣云的特征香气,丁酸乙酯、乙酸己酯、己醛为北蓝的特征香气成分,品种间特征香气的差异形成了半高丛越橘品种间独特的风味。     

发酵方法对柿果醋中香气成分的影

采用顶空固相微萃取法、结合气相色谱质谱联用技术,对自然发酵和常规发酵柿果醋中香气成分进行了分离与分析比较,分别从2种柿果醋中分离鉴定出挥发性化合物63种,均含有酯类、羧酸类、醇类、烃类、醛酮类、酚类及少量其他化合物.常规发酵柿果醋香气成分中含有酯类33.78%、醇类32.38%和烃类1.08%,高于自然发酵柿果醋的含量;自然发酵柿果醋香气成分中含有羧酸类61.25%、醛酮类9.66%和酚类6.13%,高于常规发酵柿果醋的含量.采用常规发酵法生产的柿果醋具有较好的感官质量.     

视频和GIS技术在森林防火中的应用

针对浙江省森林覆盖率高,并且发生森林火灾的频率也高,单纯的视频监控在夜晚无法识别等问题,提出了视频技术与地理信息系统技术相结合来监控森林火灾的方案。该方案是在森林的某个高程点上架设视频摄像设备,通过远程传输到达视频监控系统的后台,显示在森林地理信息系统上,然后根据显示的区域来监控森林火情。该方案通过同步跟踪算法实现视频技术与地理信息系统的融合,在森林防火地理信息系统上实时同步跟踪,能够提高森林防火的效率。     

北京怀柔水库流域土地利用变化及其驱动力研究

使用1990~2005年3期遥感影像数据作为信息源,通过GIS手段,分析怀柔水库流域近15年土地利用变化特征,利用主成分分析法,综合社会经济统计数据,定量分析怀柔水库流域土地利用变化的驱动力。分析表明:流域内阔叶林、针叶林、混交林的面积所占比例呈上升趋势,灌木林面积下降趋势明显,农田面积总体变化不大;土地利用变化和经济发展程度密切相关,与人口因素关联度不高。     

Growth and yield responses of upland NERICAs to variable water management under field conditions

This study aimed to investigate the possible causes for inconsistent performances of upland New Rice for Africa (NERICA) varieties in uplands and lowlands, while identifying important determinants in grain yield under deficient soil moisture. We compared the growth and yield of NERICA 1 and NERICA 5 to those of Yumenohatamochi, a Japanese upland variety, and Hinohikari, a Japanese lowland variety, subjected to different water management regimes (continually flooded, supplementary irrigation, and non-irrigation). Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased, whereas the panicle number of the Japanese varieties experienced little change. In contrast, the grain filling ratio was unaffected by water management, irrespective of variety. The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle, and water stress intensity was the primary factor for the degree of this reduction. Variation in the abortion of secondary rachis-branches caused differences between NERICAs in their spikelet number response to soil moisture deficiency. The inconsistency in NERICA performance across uplands vs. lowlands can be partially attributed to variation in yield response to low soil water conditions. Moreover, water stress intensity and the presence of a water gradient along the vertical soil profile may combine to affect the fluctuation in NERICA performance under upland conditions.     

花后不同强度遮光对糯小麦和非糯小麦淀粉组分和理化特性的影响

花后弱光影响小麦淀粉分子积累和结构形成,进而使面粉的加工品质和食用品质变劣。本研究以非糯小麦轮选987和糯小麦农大糯50206为材料,设置3个花后遮光处理(不遮光、遮光30%和遮光60%),研究了花后不同强度遮光对小麦籽粒中淀粉组分及其理化特性的影响。结果表明,花后弱光胁迫使小麦籽粒中总淀粉含量减少,A-型淀粉粒比例增加,淀粉相对结晶度增大。花后光照强度降低,轮选987淀粉的峰值黏度、谷值黏度、最终黏度、稀澥值和反弹值增大,而农大糯50206淀粉的上述参数则呈减小趋势。轮选987淀粉的起始温度、峰值温度和终止温度随弱光胁迫的增强而降低,而糊化焓呈增加趋势;相反,农大糯50206淀粉的上述热力学特征参数呈降低趋势。相关性分析表明,直链淀粉含量、直/支比、A-型淀粉粒体积比例与相对结晶度、峰值黏度、谷值黏度、稀澥值、糊化时间和糊化焓呈显著负相关,与最终黏度和反弹值存在极显著正相关。可见,小麦花后光照强度降低影响籽粒淀粉组分和粒度分布,从而改变了淀粉的晶体、糊化和热力学特性。     

不同基追肥比例对湖南省双季稻产量及干物质积累的影响

为探究不同基追肥比例对湖南省双季稻产量及干物质积累的影响,以‘湘早籼32号’和‘中嘉早17’为早稻供试品种,‘湘晚籼12号’和‘五优308’为晚稻供试品种,设置6种不同施肥比例(T1~T6)与1个不施肥处理(T7)。研究结果表明:施肥能有效提高水稻产量,比不施肥增产16.07%~91.33%。早稻‘中嘉早17’以基追肥比例8:2:0:0产量最高,为7497.00 kg/hm~2,晚稻‘五优308’以基追肥比例6:2:2:0产量最高,为9387.90 kg/hm~2;早晚稻的干物质积累量均以基追肥比例4:3:3:0较高,是一种有利于干物质积累的施肥方式,前轻后重的施肥方式茎秆重、叶片重、穗重显著低于其他处理,基追肥比例0:5:3:2的根系重与茎秆重分别比其他施肥处理少9.72%~63.84%和6.42%~27.82%,表明肥料后移会减少水稻干物质的积累。因此,在湖南地区重施基蘖肥可促进早稻分蘖的发生,晚稻在重施基蘖肥的基础上适当配施穗肥可增加单位面积颖花数、提高结实率,以此获得双季稻的高产。     

减氮配施生物菌剂对土壤肥力及烟叶产质量影响

为探讨生物菌剂在烤烟上的施用效果,研究了减氮配施生物菌剂对土壤肥力及烟叶产质量影响。结果表明:与常规施肥相比,减氮并配施生物菌剂处理能明显提高烟株各生育时期土壤中有机质、速效磷和速效钾含量,明显增加根际和非根际细菌和放线菌数量,烟叶产量提高172~586 kg/hm~2,产值提高8927~21357元/hm~2。烤后烟叶化学成分分析表明,与常规施肥相比,减氮并配施生物菌剂处理降低了中、上部叶总糖和还原糖含量,除处理T5(众邦)外,中部叶和上部叶烟碱含量均有明显下降,下部叶、中部叶和上部叶烟叶钾含量提高幅度为分别为0.12~0.53、0.03~0.41和0.14~0.65个百分点。不同生物菌剂间相比,以处理T4(人元)和处理T2(时科)在经济性状和烟叶化学成分协调性上表现较好。