水稻施用植物生长促进菌效果初探

通过田间试验,对一种植物生长促进菌(PGPR)在水稻上的应用效果作了初步探讨。试验结果表明,PGPR制剂与化肥配合施用对水稻生长发育产生了显著的影响。与单施氮、磷、钾化肥相比,PGPR与化肥处理显著提高了水稻的株高、穗数、穗粒数、千粒重,比单施化肥和不施肥对照分别增产26.0%和53.9%。同时,PGPR处理提高了水稻的根系活力,并对灌浆速率产生了积极的影响。     

不同浓度硝基苯对水稻发芽和秧苗生长发育的影响

试验结果表明,硝基苯浓度达到27倍(0.34 mg/L)以上对水稻发芽产生明显影响,致使芽率下降.不同浓度的硝基苯对不同品种的发芽率影响不显著.随着浓度的增加,同一品种株高基本呈降低趋势,根数、叶片与对照差异显著.     

党参根腐病病原菌鉴定及其室内毒力测定

为明确引起甘肃省渭源县党参根腐病的病原菌,并筛选防治该病害的最佳杀菌剂,试验采用组织分离法和单孢分离法对引起党参根腐病的病原菌进行了分离纯化,通过致病性测定、形态学特征、编码转录延伸因子区序列(TEF-1α)聚类分析对病原菌进行了鉴定,并采用生长速率法进行药剂毒力测定.病原鉴定结果表明,引起甘肃省渭源县党参根腐病的病原...     

根系修剪对枳生长及相关基因表达的影响

以枳实生苗为试验材料,通过两年重复试验分析了不切除主根、切除1/3主根、切除1/2主根、切除2/3主根等4个不同水平根系修剪处理下枳实生苗生长发育、根系构型和营养吸收的情况,并检测了不同水平根系修剪处理对侧根发育关键基因表达量的影响.结果表明,切除1/2主根处理增加了枳实生苗的株高、茎粗、地上部鲜重和根系鲜重,改善了根...     

三江平原主栽大豆品种对大豆根腐病尖孢镰孢菌的抗性分析

明确三江平原地区主栽大豆品种对主要大豆根腐病致病菌尖孢镰孢菌的抗性。收集了该地区主栽大豆品种13 个,对其同时进行盆栽接种和大田接种尖孢镰孢菌的抗性分析试验,大田接种试验设不接种对照。‘垦丰16’和‘合丰55’的抗性最好,盆栽试验中均表现为抗病,平均病情指数分别为15.33%和20.67%,大田接种试验中表现为抗病,病情指数分别为25.55%和22.89%,与未接种对照相比,减产率最低,分别为3.55%和3.77%,差异达到显著水平。‘垦丰16’和‘合丰55’是适宜三江平原地区种植的抗尖孢镰孢菌根腐病的抗病品种。     

氮沉降对细根动态和形态特征的影响研究进展

旨在总结前人研究经验以及过去研究的不足,指出未来N沉降对于细根影响研究的发展方向。基于前人研究的成果,总结了N沉降是如何影响细根动态和形态特征,进而又如何影响生态系统C循环。详细分析了全球N沉降现状,表明N沉降呈逐年加重的趋势;分析了细根动态（细根周转和呼吸）和形态特征（根长、直径、生物量、化学组分）对N沉降的响应。既有研究提供了很多N沉降影响细根动态和形态特征的证据,这些证据对于未来开展细根综合研究具有重要借鉴意义。     

地下水埋深对夏玉米根冠生长和耗水量的影响

利用排水式蒸渗仪,借助自制的Mariotte瓶装置,通过设置6种地下水埋深控制处理(地下水位埋深分别为0.2、0.4、0.6、0.8、1.01、.2m),探讨了不同地下水埋深对夏玉米的地上部分、根系生物量及耗水量的影响。结果表明,夏玉米株高和冠层叶面积随地下水埋深减小有增加的趋势,但是当地下水埋深减小到一定程度时就会抑制株高、叶面积,地下水埋深0.6m处理株高和叶面积系数(LAI)最大。各土层根系及其总生物量随地下水埋深增大而增大;地上部总生物量与地下部根生物量的比值随地下水埋深的增大呈明显减少的趋势。夏玉米全生育期和各阶段耗水量分别与地下水埋深呈较好的负相关关系,达到极显著水平(P<0.01);地下水补给量占耗水量的比例随地下水埋深的增大而逐步降低。研究结果可为江淮丘陵区夏玉米灌溉制度的制定及农田排水工程的设计提供参考依据。     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

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Potatoes

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After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Fresh tomatoes

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From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Processing tomatoes

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From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.     

根系分区交替滴灌条件下葡萄根系分布特征及生长动态

采用原位取土法和根系生态监测系统连续两年研究了葡萄的根系空间分布和全生育期根系生长动态,结果表明:葡萄根系在水平方向主要分布在距离树干100 cm的范围内,占到总根系的80％以上,而且在径向方向呈指数衰减;葡萄根系在垂直方向主要分布在0～60 cm范围的土层内,占到总根系的75％以上.根系分区交替滴灌条件下干燥区与湿润区根系生长是不同的,葡萄的新生根系受到土壤水分条件的限制和自身生长的影响.在整个生育期,葡萄根系分区交替滴灌两侧根系生长均呈抛物线变化.     

两种灌木根系对异质生长空间的适应分布特征

为探究灌木根系对异质空间的适应策略,以紫穗槐和胡枝子两种灌木为研究对象,采用盆栽控制生长空间的研究方法,以放置不同形状的木板在盆内模拟不同喀斯特异质空间条件(孔隙型、圆形裂缝型、条形裂缝型和孔隙+岩石阻挡型),研究了异质空间条件下两种灌木根系分布特征。结果表明:(1)异质空间条件下紫穗槐和胡枝子根系各项指标均高于均质空间,异质空间条件对根系生长有促进作用。不同植物受异质空间的影响程度不同,胡枝子在异质空间下的根系生物量显著高于均质空间。不同异质空间对根系生长的影响不同,紫穗槐和胡枝子根系均在孔隙型和圆形裂缝型两种空间条件下最为发达。(2)紫穗槐和胡枝子根生物量分布特征受异质空间影响。在异质空间下两种树种根生物量的垂直分布均集中分布在土层深度5—10 cm和15—20 cm范围内,水平分布均集中分布在距植株中心0—3 cm内。紫穗槐根系生物量的水平分布受异质空间具体形状影响较大,孔隙型空间和圆形裂缝型空间对其水平分布影响较为显著。(3)两种灌木对异质空间的适应策略不同,紫穗槐根系对异质空间的适应策略为寻找更多空间,而胡枝子根系对异质空间的适应策略为占据有限空间。综上,紫穗槐和胡枝子根系生...