桉树无性系GL-UG9叶面积回归分析及其应用研究

以2年生桉树无性系GL-UG9的叶片为试验材料,利用叶面积仪测定其叶长、叶宽指标,计算出叶面积与相关指标的回归方程。结果表明:回归方程与上述指标均呈直线相关,经F检验差异达到极显著水平(p<0.01),尤其是多元回归方程y=11.753x1+4.037x2-90.805和y=-12.122x2+16.346x3-0.028x4-94.361,相关系数高达0.992 3。通过分析发现,利用回归方程测出的叶面积值与仪器实测值极为接近,该方程式为桉树无性系GL-UG9叶面积的活体测定提供了一个简单实用的测定方法。     

中天地公司商品林基地合理主伐量的测算与论证

根据四川中天地木业有限公司(以下简称中天地公司)商品林基地用材林森林资源现状,采用多种方法测算了用材林年主伐量,分析、论证了各类测算方法和测算结果的合理性,确定了该基地合理年主伐量。     

旱涝急转条件下红壤坡地径流养分流失特征研究

为了研究旱涝急转条件下红壤坡地地表径流、壤中流及其养分流失规律,通过径流小区试验,分析对比在旱涝急转条件下,裸露(CK)、百喜草全园敷盖(T1)和百喜草全园覆盖(T2)措施下红壤坡地地表径流和壤中流产流及总氮、总磷流失特征。结果表明,旱涝急转条件下,地表径流产流过程随着雨强的变化而变化,壤中流产流开始后径流过程与地表径流相似;地表径流和30cm壤中流养分流失呈现先增大后减小最终趋于稳定的趋势,60cm壤中流和105cm壤中流养分质量浓度相对稳定;T2处理对于减少径流养分流失的效果最好,地表径流和壤中流径流量分别为CK的32.89%和45.05%,径流中养分质量浓度也明显降低。     

2CZY-2型甘蔗种植机试验和分析

对2CZY-2型甘蔗种植机作业性能行了试验测试,并与人工作业进行了比较分析,对存在的不足进行了改进试验。结果表明：2CZY-2型甘蔗种植机性能稳定,机械化种植工效是人工的4倍、成本比人工降低489元/hm2,经济效益和社会效益显著,为甘蔗机械化的发展提供重要的实践和理论依据。     

马铃薯嫁接番茄的试验研究

利用马铃薯苗茎作砧木,用番茄的嫩枝作接穗,进行嫁接试验.结果表明:两者嫁接后不仅可以成活,而且可以结出无异常口味的番茄和马铃薯.能否嫁接成活与嫁接时砧木茎粗、木质化程度有一定关系,砧木直径大于0.4 cm、小于0.8 cm、无木质化时,嫁接成活率较高.樱桃番茄的接后表现明显优于大番茄.     

不同种植年限蔬菜大棚土壤中硝态氮时空变异研究

本研究旨在通过对青海乐都地区不同种植年限蔬菜大棚土壤情况的调查,了解该地设施蔬菜生产中土壤硝态氟时空变异.2～27 a设施蔬菜0～100 cm土壤中硝态氮含量为99.09～609.065 mg/kg;0～20 cm土壤中硝态氮含量为37.51～545.545 mg/kg,总盐含量为0.137%～0.671%,pH变化为...     

In vitro study of possible role of dietary fiber in lowering postprandial serum glucose

There have been many reports concerning the role of dietary fiber in lowering postprandial serum glucose, and the main mechanism was regarded as the viscosity of different dietary fibers in hampering diffusion of glucose and postponing absorption and digestion of carbohydrates. In this paper, two kinds of water-insoluble dietary fibers, water-insoluble dietary fiber of wheat bran and enzyme-resistant starch of maize amylose, and four kinds of water-soluble dietary fibers, water-soluble dietary fiber of wheat bran, carboxymethyl cellulose, guar gum, and xanthan gum, were used to investigate their postprandial serum glucose lowering mechanism in vitro. The results showed that these dietary fibers lowered postprandial serum glucose levels at least by three mechanisms. First, dietary fibers increase the viscosity of small intestine juice and hinder diffusion of glucose; second, they bind glucose and decrease the concentration of available glucose in the small intestine; and, third, they retard alpha-amylase action through capsuling starch and the enzyme and might directly inhibit the enzyme. All of these decreased the absorption rate of glucose and the concentration of postprandial serum glucose.     

生态遗传雄性不育理论与两系杂交植物Ⅲ．生态遗传雄性不育系的鉴定方法

论述了生态遗传（光、温敏）雄性不育系的鉴定标准和方法。指出可供采用的生态遗传雄性不育系的育性表达必须在年际间表现稳定，在雄性不育阶段其不育株率应达到１００％，深不育单株不育度应达到９９．５％以上，浅不育单株不育度应达到９０％以上；在雄性可育阶段其可染花粉率应达到６０％以上，异交结实率应达到５０％以上。不论是长日光敏感型、短日光敏感型，还是高温敏感型或低温敏感型的雄性不育系，其育性鉴定应当同时在自然光温条件下、自然变温控制光周期条件下和人工定温控制光周期条件下进行。     

Elastic Buckling and Critical Load of an Pre- stressing Arch

According to the field theory of additional deformation on pre - stressed configuration , in the paper , the ordinary expression of the governing equation and variational equation of elastic buckling are brought forward . Under the theory system, through lowering dimensions, the governing equation and variational equation for the critical condition solution of elastic buckling of a plane arch are deduced, and the eigenvalues problem of the linear homogeneous differential equations corresponding to the equations are concluded While Abandoning the plane assumption and considering shearing deformation, the linear finite element method arithmetic of bending bar's cross section containing six degree of freedom is given. The process of derivation and calculational results show that, under this system info, the finite element equations of bending bar deduced are accurate and easy to be used to numeric calculations, and the conclusion achieved is more practical.