【目的】探究马唐对旱直播稻生长和产量性状的影响以及其防治经济阈值,为旱直播稻田马唐的防除提供理论依据。【方法】以常规稻象牙香占为试验材料,设置1 m ^(2)独立池为1个小区,每小区播种旱直播稻32穴。对马唐设置8个不同密度(0(CK),2...【目的】探究马唐对旱直播稻生长和产量性状的影响以及其防治经济阈值,为旱直播稻田马唐的防除提供理论依据。【方法】以常规稻象牙香占为试验材料,设置1 m ^(2)独立池为1个小区,每小区播种旱直播稻32穴。对马唐设置8个不同密度(0(CK),2,4,8,16,32,64和128株/m^(2))处理,将其均匀种植在相邻4株旱直播稻的中心位置,每处理重复3次,随机区组排列,研究马唐密度对旱直播稻分蘖数、株高、田间透光率及产量性状的影响,采用不同回归模型拟合马唐密度(x)与水稻产量损失率(y)间的函数关系,并根据经济危害允许水平计算马唐在旱直播稻田的防治经济阈值。【结果】随着马唐密度的增加,旱直播稻的分蘖数、株高和田间透光率均明显下降;与CK相比,当马唐密度为128株/m^(2)时,旱直播稻播种后60 d的分蘖数减少了83.5%,播种后74 d的株高降低24.4%,播种后75 d的田间透光率(离地75 cm)降低80.91%。马唐对旱直播稻的有效穗数、穗粒数、结实率、千粒质量和产量均可造成影响,当马唐密度为2~128株/m^(2)时,旱直播稻产量损失率为5.95%~90.92%。相关性分析结果表明,马唐密度与旱直播稻的有效穗数、穗粒数、结实率、千粒质量和产量均呈极显著负相关(P<0.01)。指数函数y=91.7837(1^(-e-0.0525 x))更好地拟合了马唐密度(x)与旱直播稻产量损失率(y)之间的关系。结合不同除草方式的经济危害允许水平,人工防除马唐的经济阈值为3.79株/m^(2),植保无人机和背负式喷雾器喷施10%噁唑酰草胺防治马唐的经济阈值分别为0.63和1.06株/m^(2)。【结论】马唐可通过影响旱直播稻的生长和产量性状导致旱直播稻严重减产,利用植保无人机防治马唐具有明显的经济优势,其防治经济阈值为0.63株/m^(2)。展开更多
Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polya...Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polyacrylic acid/chitosan(PAA/CS)cryogels were prepared by a cryostructurization technique to improve mechanical performance and hemostatic efficiency of chitosan(CS).In this system,the chemically cross-linked PAA network was used as a framework to improve water absorption behaviors and mechanical strength.The CS network was co-blended by hydrogen bonding and electrostatic interactions,both of which synergistically promoted hemostasis.These cryogels had high porosity(>94%),rapid water absorption rate(<3 s),high blood absorption capacity(>2000%),outstanding mechanical strength,and fatigue resistance.Moreover,the results of cytotoxicity and hemolysis demonstrated that the cryogels had good biocompatibility.Notably,the PAA/CS cryogels exhibited superior whole blood coagulation ability and red blood cell and platelet adhesion ability compared to those of commercial hemostatic dressing(gauze,gelatin sponges,and CS sponges).Based on these results,mouse femoral artery hemorrhage models and liver hemorrhage models were prepared to investigate the hemostatic ability of the prepared PAA/CS cryogels.Results suggested that the hemostatic ability of PAA5/CS cryogels was superior to that of commercial hemostatic materials.Therefore,the PAA/CS cryogels showed potential application in preventing massive hemorrhage from arteries and visceral organs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U20A20261,31870948,31971250,and 52073205)Natural Science Foundation of Tianjin(Grant No.20JCYBJC00660)。
文摘Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polyacrylic acid/chitosan(PAA/CS)cryogels were prepared by a cryostructurization technique to improve mechanical performance and hemostatic efficiency of chitosan(CS).In this system,the chemically cross-linked PAA network was used as a framework to improve water absorption behaviors and mechanical strength.The CS network was co-blended by hydrogen bonding and electrostatic interactions,both of which synergistically promoted hemostasis.These cryogels had high porosity(>94%),rapid water absorption rate(<3 s),high blood absorption capacity(>2000%),outstanding mechanical strength,and fatigue resistance.Moreover,the results of cytotoxicity and hemolysis demonstrated that the cryogels had good biocompatibility.Notably,the PAA/CS cryogels exhibited superior whole blood coagulation ability and red blood cell and platelet adhesion ability compared to those of commercial hemostatic dressing(gauze,gelatin sponges,and CS sponges).Based on these results,mouse femoral artery hemorrhage models and liver hemorrhage models were prepared to investigate the hemostatic ability of the prepared PAA/CS cryogels.Results suggested that the hemostatic ability of PAA5/CS cryogels was superior to that of commercial hemostatic materials.Therefore,the PAA/CS cryogels showed potential application in preventing massive hemorrhage from arteries and visceral organs.
