不同品种胡萝卜后代分离研究

胡萝卜营养价值高,耐贮藏,生产鲜食品种具有良好的发展前景。为了加快我国"微型"胡萝卜的发展,对5个胡萝卜品种自然授粉后代的单根长、根粗等性状进行了调查分析,以期筛选出适宜在当地种植并且外观符合"微型"胡萝卜要求的优良单株后代。结果表明,5个品种胡萝卜后代的不同单株间性状均出现分离,Little Finger B和Scarlet Nantes A这2个品种后代的根长性状分离较小,变异系数只有22.60%和24.09%,而且根长较大;Baby Finger,Scarlet Nantes B和Little Finger B这3个品种后代胡萝卜的根粗都较小,其中,以Baby Finger的变异系数(18.91%)最小。研究结果可为胡萝卜育种中优良单株的选择提供重要依据。

庞庄矿张小楼新副井提升绳更换施工工艺

庞庄矿张小楼新副井井深、提升量大,导致提升钢丝磨损和断丝加剧,实际使用年限不到一年,更换频繁。针对张小楼井深绳重,换绳施工难度大的特点,对其施工工艺进行了探讨,并提出了施工过程中应注意的控制措施。

MODELING AND ANALYSIS OF SALT TRANSPORT IN THE SINGLE CYLINDRICAL ROOT WITH FINITE LENGTH

A mathematical model for salt transport by a cylindrical root in an infinite extent of soil is derived and solved analytically by asymptotic matching of the inner and outer solutions. By asymptotic analysis it is shown that the salt solution uptake by a single cylindrical root in the absence of competition does not influence the overall salt concentration in the soil even when the soil moisture concentration is less than full saturation.