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201.
[Object] To setup the hyperspectral sensing models for estimating SPAD value of cotton leaves under waterlogging stress. [Method] Irrigation and drainage controllable plots were introduced to simulate the waterlogging stress treatment in the flowering and boll forming stage, during which the change characteristics of the cotton leaf spectral reflectance and SPAD value were observed after 1 d, 3 d, 6 d, 9 d waterlogging, respectively. To find out the hyperspectral sensing models for estimating SPAD value of cotton leaves under waterlogging stress, the correlation and regression relationships between SPAD value and spectrum parameters were analyzed. [Result] (1) The SPAD value of the fourth cotton leaf from the top was significantly lower than control when suffers from waterlogging for 3 d, when waterlogged 9 d the SPAD value decreased by around 15% compared with the control. (2) The cotton suffering from waterlogged damage in the flowering and boll forming stage caused the reflection peak in green light wave band became steep, while the near infrared spectral reflectance increased, and caused the reduction of red absorption and red edge position "blue shifts", the red edge position drifts towards short wave with 4~5 nm when suffers from waterlogging for 9 d. With increase of the waterlogged days, the red edge slope and red edge area increased with a maximum value at 6 d of waterlogging, meanwhile, the skewness and kurtosis of red edge increased. (3) After waterlogging, the SPAD value of the fourth cotton leaf from the top (chlorophyll content) had a remarkable correlation with red edge slope(Dr), red edge position(λr), green peak reflection(Rg), green peak position(λg), red well position(λo), blue edge area(SDb), yellow edge skewness(Sy), yellow edge kurtosis(Ky), red edge skewness(Sr), red edge kurtosis(Kr), etc. An experience linear, polynomial and exponential models for estimating SPAD value had been built through using the Sy, Sr, Kr as independent variables, respectively, their determination coefficient (R2) were greater than 0.9, and the root mean square error (RMSE) were less than 1; and an experience binary linear regression equation for estimating SPAD value had been built through multivariate regression using the λg, SDr/SDb(VI3), Sb, Sy, Ky as independent variables, the R2 was as high as 0.973, and the RMSE was 0.393. [Conclusion] The model can be remote sensing model used as estimating leaf SPAD of cotton value under waterlogging stress. 相似文献
202.
土壤中根皮苷和根皮素对桃幼苗的影响 总被引:1,自引:0,他引:1
以一年生桃嫁接苗为试材,在盆栽条件下研究了苹果园土壤中特征酚酸类物质——根皮苷和根皮素对桃苗生物量、根系活力、根系保护性酶活性和MDA含量的影响。结果表明,根皮苷对桃幼苗的伤害显著,与对照相比,鲜质量、干质量分别降低了16.66%和21.58%,根系活力降低了33.04%,SOD、POD活性分别降低了40.80%和31.10%,MDA含量提高了116.34%。根皮素对桃苗的影响不大。高锰酸钾处理明显缓解了根皮苷对桃苗的伤害,苹果园土壤中的根皮苷含量降低了57.80%,提高了桃苗的生物量、根系活力和保护性酶活性,降低了MDA含量。综上,老龄苹果园土壤实测含量的根皮苷(0.343mg·kg~(-1))可降低桃苗的生物量,适量的高锰酸钾能缓解根皮苷的伤害作用。 相似文献
203.
基于商业模式创新中介效应,依据全国314家企业问卷调查的样本数据,运用多元线性回归方法,考量网络嵌入性、商业模式创新和企业竞争优势之间关系,结果发现:关系嵌入性、结构嵌入性与竞争优势均有显著的正向关系;商业模式创新在关系嵌入性、结构嵌入性与企业竞争优势的关系中起着中介作用。鉴此,企业应注重构建不同形式的网络嵌入,推动商业模式的调整与变革,以提高企业竞争优势。 相似文献
204.
205.
针对氢氧化钠作用下水合肼还原硒形成Na2Se2 与磺酸酯反应制备二烷基二硒醚需要在高温(100 ℃)下才能有效进行,且仅适用于制备不含官能团的二烷基二硒醚的问题.由于铯离子体积大, 与阴离子之间的静电作用弱, 使与之键合的阴离子表现出强的碱性和亲核性,利用铯碱作缩合剂,能显著降低反应的活化能, 使许多反应在温和条件下就能有效进行.根据离子交换原理,采用氯化铯和TBAI作催化剂, 以无水DMF作溶剂, 4A分子筛作吸水剂, 氢氧化钾促进肼还原硒, 随后与含官能团的卤代烃或磺酸酯反应, 高收率地形成对应的二烷基二硒醚.本方法不仅可以合成含官能团的二硒醚,而且具有反应条件温和、产率高等优点. 相似文献
206.
207.
WANG Huaqing GAO Qingshan JIANG Wenjie ZHAO Yuhan JIN Qingguo LI Yinghua XU Yongnan 《中国畜牧兽医》2019,46(2):497-503
To investigate the effect of histone deacetylation inhibitor Psammaplin A (PsA) on the development of bovine aging oocytes in vitro,oocytes were randomly divided into control group,aging group and 50 mmol/L PsA treated aging group (PsA group).Immunofluorescence staining and JC-1 were used to detect the blastocyst rate of bovine oocytes after parthenogenetic activation,the number of cells in blastocysts,apoptosis,reactive oxygen species (ROS),glutathione (GSH) and mitochondrial membrane potential intensity of embryos.The results showed that the blastocyst rate of the aging group was significantly lower than that of PsA and control groups (P<0.05).The blastocyst rate of PsA group was not significantly different from that of control group (P>0.05).The number of cells in the blastocysts of control group and PsA group were significantly higher than that of aging group (P<0.05).The number of cells in the blastocysts of PsA group was not significantly different from that of control group (P>0.05).The apoptosis rate in aging group was significantly higher than that of control and PsA groups (P<0.05),the apoptosis rate of PsA group was significantly higher than that of control group (P<0.05).The GSH level of MⅡ oocytes in aging group was significantly lower than that of control and PsA groups (P<0.05).There was no significant difference in GSH level between control and PsA groups (P>0.05).The ROS level of the embryos in aging group was significantly higher than that of control and PsA groups (P<0.05).The ROS level in PsA group was significantly higher than that of control group (P<0.05).The mitochondrial membrane potential of early embryos of aging group 4-8 cells was significantly lower than that of control and PsA groups (P<0.05).The mitochondrial membrane potential intensity of control group was significantly higher than that of PsA group (P<0.05).In summary,PsA could effectively delay the aging of bovine oocytes and improve the quality of oocytes. 相似文献
208.
山东省胶莱盆地的高岗部位存在大量的风尘堆积物,对其年代的研究一直存在较大的分歧.对胶莱盆地的潍坊前埠下风尘堆积剖面进行了系统的光释光年代测试,并与其以北16.9km的昌邑县徐林庄剖面的年代进行了对比,初步建立了胶莱盆地风尘堆积的光释光年代序列,研究表明该区风尘堆积主要是晚第四纪以来形成的堆积物. 相似文献
209.
210.