盐逆境胁迫下施钾对降低小麦盐害的生理效应研究

在盐逆境下施用钾肥可以增加小麦灌浆期旗叶的叶绿素含量,延长叶片的功能期,提高植株叶片的K+及K+/Na+,增强叶片的保水能力,提高旗叶光合速率和籽粒产量。在本试验条件下,以施用K2O 90kg/hm2处理效果最佳,在此基础上再增加施钾量则效果下降。     

Abnormally modified tau and hypoxic-ischemic brain damage

Tau is the most abundant microtubule-associated protein in the brain. If tau protein lost the normal function, the toxic effect should be showed and plays an important role in various central nervous system lesions. Hypoxic-ischemic encephalopathy (HIE) is an important cause of mortality in the neonatal period and it is mainly characterized by neurological deficits such as cognitive limitations. However, the mechanism still needs further study, and the underlying relationship between tau protein and HIE lacks direct evidence. Some recent clinical study reported that tau protein expression elevated in the serum of asphyxia children and had a high correlation with behavior deficient. In this review, we focus on 3 key points to provide new insights to understand the tau protein-related pathogenesis of HIE as followed: (1) tau protein and its phosphorylation change during central nervous system development; (2) comparison of tau protein expression in developing brain and adult brain under some neurological disorders; (3) potential pathological change of tau in HIE related pathological conditions, such as dysmyelination, inflammation response and glutamate metabolism.     

毕节地区新造林地鼠兔危害状况调查及防控对策

对啮齿类动物鼠兔害的防治.危害调查、标本制作、种类鉴定、生活习性观察,探索有效控制措施.本文着重从森林环境资源的核算评估鼠兔害对新造林地经济损失.     

一种新型玉米收获机摘穗装置设计与分析

分析了玉米收获机械的发展现状,针对现有摘穗装置的缺点,设计了一种利用惯性摘穗的装置,并设计了配套输送装置;利用摘穗原理的创新,从根本上解决了玉米收获机对籽粒造成损伤的问题;理论计算验证了摘穗的可行性,利用仿真分析验证了理论计算结果的正确性;同时分析比较了两种秸秆处理方式的优缺点.     

Timber quality after thinning from above and below in stands of Pinus sylvestris

Timber quality and logging damage after different thinning types in Scots pine (Pinus sylvestris L.) stands were studied in a field experiment in north Sweden. Thinning operations were mechanized and carried out according to normal Swedish practise. The treatments were thinning from below and thinning from above. The quality of the residual stand was evaluated using variables such as diameter of the thickest branch, stem taper, annual ring width, straightness and lean of trees. The only variables showing differences between treatments were lean of tree and stem straightness. No difference in the frequency of trees with logging damage was found. The conclusion of this study is that differences between thinning types in first thinning may be evened out when carried out as in commercial forestry due to extraction of strip road and damaged trees. Consequently, differences in timber quality and logging damage in the residual stand may be small.     

果蝇对云南杨梅的危害及发生规律研究初报

通过对云南杨梅主产区的果蝇种类鉴定、栖息场所及危害发生规律调查,结果表明：危害云南杨梅果实的主要害虫为双翅目（Diptera）果蝇科（Drosopilidaes）果蝇属（Drosophila）果蝇.果蝇广泛分布于杨梅园及其周边多种生态环境,具有发酵物、潮湿阴凉的生态环境,是果蝇栖息的主要场所和主要虫源;成虫的日活动高峰期为清晨和黄昏;果蝇对杨梅发生危害时期较早,杨梅生长中后期,果实肉质生硬,味酸稍甜时即被果蝇取食危害,随着杨梅的不断成熟,危害加剧,且果蝇对不同杨梅品种的危害程度和空间分布存在显著差异.     

黄淮冬麦区晚霜冻易发时段冠层内最低气温分布及估算

利用2016年和2017年3月中旬?4月下旬两次典型低温过程中,冬小麦田间不同高度逐小时气象观测数据,分析晚霜冻易发时段冬小麦冠层内最低气温出现高度及其变化规律,构建基于150cm高度处气象因子和地表0cm温度的冠层内最低气温估算模型。结果表明：（1）与150cm高度相比,两次典型低温过程中0℃以下气温在冠层高度附近出现时间更早,持续时间更长且温度更低;（2）最低气温总是出现在4/5冠层高度附近,并在2：00?6：00时段,尤以5：00左右发生频率最高;（3）冠层内最低气温与150cm高度处相对湿度、风速的相关性通过了0.01水平的显著性检验,与不同高度气温、不同土壤深度地温的相关性也通过了0.001水平的显著性检验,与地温的相关性随着土壤深度的增加而逐渐降低;（4）冠层内最低气温与150cm高度处气温、风速、相对湿度,以及0cm地温的偏相关系数大小排序表现为,气温＞风速＞地温＞相对湿度;利用以上因子构建基于多元线性回归函数的冠层内最低气温估测模型,其估测值与实测值拟合结果的决定系数达到0.967,均方根误差为0.915。说明基于气象台站常规观测数据构建冠层内最低气温估测模型具备一定可行性,可为冬小麦晚霜冻害的监测预报提供数据支持。     

不同种植年限对菜地土壤结构的影响

为了探究不同种植年限对菜地土壤结构的影响情况,为土壤培肥提出切实可行的方法,采用萨维诺夫法分析了重庆市九龙坡区白市驿镇蔬菜基地种植1年、5年、10年的菜地土壤团聚体的组成情况及其差异。结果表明：水稳性团聚体含量以及稳定性在不同种植年限土壤间存在较大差异。对于0~20 cm土层土壤,1~0.25 mm、>3 mm和>5 mm水稳性团聚体含量均表现为1年>5年>10年,20~40 cm土层也存在类似变化。表明随着种植年限的增加,各土层土壤水稳性团聚体含量逐渐降低。对于0~20 cm土层,1年土壤>0.25 mm团聚体平均破坏率为27.78%,5年和10年土壤>0.25 mm团聚体平均破坏率分别高达49.86%、58.74%;对于各种植年限土壤20~40 cm土层也存在相同的趋势。说明随着种植年限的增加,土壤团聚体破坏率增高,土壤结构稳定性降低。相关分析表明,土壤有机质含量与种植年限、平均破坏率呈显著负相关（相关系数分别为-0.880*、-0.897*、n=6）,与>0.25 mm水稳性团聚体含量、>3 mm水稳性团聚体含量、>5 mm水稳性团聚体含量、3~1 mm水稳性团聚体含量、1~0.25 mm水稳性团聚体含量呈显著正相关（相关系数分别为0.897*、0.868*、0.859*、0.835*、0.829*、n=6）,土壤团聚体MWD与>0.25 mm水稳性团聚体含量之间达到极显著正相关（相关系数为0.985**,n=6）。说明随着种植年限增加,土壤有机质含量降低,水稳性团聚体含量增加,平均破坏率逐渐增加。>0.25 mm的水稳性团聚体含量越多,土壤平均重量直径(MWD)值越大,土壤团聚体稳定性越强。有机质含量是影响研究区紫色土土壤水稳性团聚体含量及稳定性的主要因素。     

Na+ Retention in the Root is a Key Adaptive Mechanism to Low and High Salinity in the Glycophyte,Talinum paniculatum (Jacq.) Gaertn. (Portulacaceae)

Talinum paniculatum is an important leafy vegetable and medicinal plant, used in many parts of South America, Africa and Asia. Its adaptation to abiotic stress has received little attention and therefore worthy of interest, especially as environmental conditions are rendering arable lands increasingly unfavourable for agriculture. Therefore, this study was undertaken to examine the influence of salt stress on the vegetative growth of the plant by subjecting seedlings to 0, 25, 50, 100, 200 and 300 mm NaCl stress for 10 days. The dry weight, ion concentrations, relative water content, oxidative damage, proline, osmotic potential and some antioxidants were determined. The plants were found to retain Na⁺ mainly in the root, with less affected leaf K⁺ concentration, and consequently very low shoot Na⁺/K⁺ ratios (<0.2) under all the stress treatments. The proline content significantly increased under the 100–300 mm treatments (18‐ to 244‐fold), with a corresponding significant reduction in osmotic potential and hence high osmotic adjustment. The antioxidant enzyme activities and non‐enzyme antioxidants showed significant increase only under the highest salinity. Taken together, these results suggest that shoot Na⁺ exclusion is characteristic of this plant and is mainly responsible for its adaptation to low salinity.     

外来入侵杂草刺果瓜（Sicyos angulatus L.） 严重危害玉米

刺果瓜（Sicyos angulatusL.）为葫芦科野胡瓜属一年生攀援草本植物,生长扩展速度快,种子量大、繁殖力极强。该杂草原产于美国,我国仅在台湾和大连地区发生。2013年本研究调查发现,刺果瓜于2002年在宣化区屈家庄首次发生,目前已导致张家口地区约400 hm2玉米受害,造成减产50%~80%。刺果瓜的生长、入侵、传播途径和防控技术等尚不清楚,急需进行深入研究。