This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla×Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed ...This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla×Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed on the seedlings at weekly intervals. Water stress was induced by suspending irrigation until the soil reached 30% available water and water was then replaced so that it returned to field capacity. Gas exchange and leaf water status were measured after 50 days. The experiment was set up in a 4×2 factorial randomized block design in four distinct environments:(1) temperatures less than 21.2℃ and vapor pressure deficit of 0.15 kPa;(2) intermediate temperatures of 24.2℃ and vapor pressure deficit of 0.69 kPa;(3) high temperatures of 27.0℃ and high vapor pressure deficit of 1.4 kPa; and,(4) high temperature of 27.0℃ and vapor pressure deficit below 1.10 kPa. Two leaf sun protector treatments were used, with five replications each. High atmospheric demand acted as a stress factor for the seedlings during the initial growth phase.Applications of leaf sunscreen protector provided beneficial effects in maintaining optimum water status and gas exchanges of the plants under water stress.展开更多
采用二因素三水平法设计模拟氮(N)、硫(S)沉降的盆栽试验,以Na2SO4为硫源、46%CO(NH2)2为氮源,其中氮沉降梯度为N1(0 kg hm-2 a-1)、N2(50 kg hm-2 a-1)、N3(100 kg hm-2 a-1),硫沉降梯度为S1(0 kg hm-2 a-1)、S2(15kg hm-2 a-1)、S3(30...采用二因素三水平法设计模拟氮(N)、硫(S)沉降的盆栽试验,以Na2SO4为硫源、46%CO(NH2)2为氮源,其中氮沉降梯度为N1(0 kg hm-2 a-1)、N2(50 kg hm-2 a-1)、N3(100 kg hm-2 a-1),硫沉降梯度为S1(0 kg hm-2 a-1)、S2(15kg hm-2 a-1)、S3(30 kg hm-2 a-1).模拟试验6个月后,测定尾巨桉(Eucalyptus urophylla×Eucalyptus grandis)和杉木(Cunninghamia lanceolata)幼苗的SPAD值、可溶性蛋白含量、净光合速率(Pn)和叶绿素荧光参数,分析探讨氮、硫沉降处理下两树种幼苗光合特性的响应机制.结果表明:与空白对照组相比,单一中氮沉降显著促进两树种幼苗Pn的上升(P<0.05),且单一高氮沉降显著促进杉木幼苗可溶性蛋白含量的上升(P<0.05),表明单一氮处理在一定程度上提高了两树种幼苗的光合能力.尾巨桉幼苗各光合指标受单一硫沉降胁迫的影响较杉木幼苗更为显著,前者的SPAD值和可溶性蛋白含量在中硫处理下均显著下降(P<0.05),Pn反之;而后者仅SPAD值在中、高硫处理下显著上升(P<0.05).氮、硫复合沉降下,尾巨桉幼苗各项指标未见明显变化(P>0.05);杉木幼苗仅中氮高硫组的SPAD值和高氮高硫组的可溶性蛋白含量显著上升(P<0.05).综上,与单一氮、硫沉降相比,氮、硫复合沉降的交互效应并未显著增强两树种幼苗的光合特性,但两树种幼苗间对模拟氮、硫沉降的响应和耐受机制存在差异.展开更多
文摘This experiment was carried out in acclimatized greenhouses with seedlings of two hybrid clones of Eucalyptus urophylla×Eucalyptus grandis. A sunscreen protector consisting of 62.5% calcium carbonate was sprayed on the seedlings at weekly intervals. Water stress was induced by suspending irrigation until the soil reached 30% available water and water was then replaced so that it returned to field capacity. Gas exchange and leaf water status were measured after 50 days. The experiment was set up in a 4×2 factorial randomized block design in four distinct environments:(1) temperatures less than 21.2℃ and vapor pressure deficit of 0.15 kPa;(2) intermediate temperatures of 24.2℃ and vapor pressure deficit of 0.69 kPa;(3) high temperatures of 27.0℃ and high vapor pressure deficit of 1.4 kPa; and,(4) high temperature of 27.0℃ and vapor pressure deficit below 1.10 kPa. Two leaf sun protector treatments were used, with five replications each. High atmospheric demand acted as a stress factor for the seedlings during the initial growth phase.Applications of leaf sunscreen protector provided beneficial effects in maintaining optimum water status and gas exchanges of the plants under water stress.
文摘采用二因素三水平法设计模拟氮(N)、硫(S)沉降的盆栽试验,以Na2SO4为硫源、46%CO(NH2)2为氮源,其中氮沉降梯度为N1(0 kg hm-2 a-1)、N2(50 kg hm-2 a-1)、N3(100 kg hm-2 a-1),硫沉降梯度为S1(0 kg hm-2 a-1)、S2(15kg hm-2 a-1)、S3(30 kg hm-2 a-1).模拟试验6个月后,测定尾巨桉(Eucalyptus urophylla×Eucalyptus grandis)和杉木(Cunninghamia lanceolata)幼苗的SPAD值、可溶性蛋白含量、净光合速率(Pn)和叶绿素荧光参数,分析探讨氮、硫沉降处理下两树种幼苗光合特性的响应机制.结果表明:与空白对照组相比,单一中氮沉降显著促进两树种幼苗Pn的上升(P<0.05),且单一高氮沉降显著促进杉木幼苗可溶性蛋白含量的上升(P<0.05),表明单一氮处理在一定程度上提高了两树种幼苗的光合能力.尾巨桉幼苗各光合指标受单一硫沉降胁迫的影响较杉木幼苗更为显著,前者的SPAD值和可溶性蛋白含量在中硫处理下均显著下降(P<0.05),Pn反之;而后者仅SPAD值在中、高硫处理下显著上升(P<0.05).氮、硫复合沉降下,尾巨桉幼苗各项指标未见明显变化(P>0.05);杉木幼苗仅中氮高硫组的SPAD值和高氮高硫组的可溶性蛋白含量显著上升(P<0.05).综上,与单一氮、硫沉降相比,氮、硫复合沉降的交互效应并未显著增强两树种幼苗的光合特性,但两树种幼苗间对模拟氮、硫沉降的响应和耐受机制存在差异.
