Morphological,Biochemical and Genetic Analysis of a Brittle Stalk Mutant of Maize Inserted by Mutator

Mutants on stalk strength are essential materials for the studies on the formation of plant cell wall.In this study,a brittle stalk mutant of maize,designated as Bk-x,was screened from a Mutator inserted mutant library.At the germination and early seedling stage,the mutant plants were indistinguishable from the normal ones.However,all of the plant organs were brittle after the 5th-leaf stage and remained brittle throughout the rest of the growing period.Microstructure observation showed that the cell wall in vascular bundle sheath of Bk-x was thinner than that in normal plants.The leaf mechanical strength in Bk-x was 77.9% of that in normal plants growing at Xishuangbanna（BN）,Yunnan province and that was 61.7% in Wuhan（WH）,Hubei Province,China.The proportion of cellulose was 12.3% in Bk-x,which was significantly lower than that in normal plants（26.7%）,while the soluble sugar content was 36.1% in Bk-x,which is significantly higher than that in normal plants（12.4%）.Genetic analysis using two F 2 populations and one F 2：3 families demonstrated that the trait of brittle stalk is controlled by a single recessive gene.

青岛市5家三级甲等医院心内科护士职业呼唤、心理资本和职业倦怠相关分析

目的探讨青岛市5家三级甲等医院心内科护士职业呼唤、心理资本和职业倦怠的相关性。方法 2020年10—12月,以青岛市5家三级甲等医院的248名心内科护士作为调查对象,使用一般资料量表、职业呼唤量表、心理资本量表、职业倦怠量表进行调查分析。结果心内科护士职业呼唤得分为43.56±8.24,心理资本得分为82.46±18.22,职业倦怠得分为64.27±14.26。不同年龄、工龄、职称、月收入、每月夜班数的内科护士职业呼唤得分比较,差异均有统计学意义(均P<0.01);不同年龄、工龄、职称、月收入的内科护士心理资本得分比较,差异均有统计学意义(均P<0.01);不同年龄、工龄、职称、每月夜班数的内科护士职业倦怠得分比较,差异均有统计学意义(均P<0.05)。心内科护士职业呼唤得分与职业倦怠得分呈负相关(r=-0.586,P<0.01),心理资本得分与职业倦怠得分呈负相关(r=-0.497,P<0.01),职业呼唤得分与心理资本得分呈正相关(r=0.624,P<0.01)。结构方程模型显示,心理资本在心内科护士职业呼唤与职业倦怠之间有负向的中介作用,中介效应为-0.222,占总效应的42.21%。结论青岛市5家三级甲等医院心内科护士职业呼唤得分处于中等水平,职业呼唤和心理资本与职业倦怠密切相关,心理资本在职业呼唤与职业倦怠之间有负向的中介作用,护理管理者应注重职业呼唤和心理资本的开发,从而降低职业倦怠。