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...
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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.
为探究高效解磷菌株与土壤磷素含量之间的关系,提高土地连载生产力,利用课题组前期筛选的3株高效解磷菌P19(A)、P7(B)、YP17(C)作为解磷菌剂,以盆栽巨尾桉幼苗作为研究对象,以3种森林土壤和未有植被覆盖的砖红壤作为基质进行盆栽试验,设置3个菌浓度处理——较高浓度107 cfu mL-1(a)、中等浓度0.5×107 cfu mL-1(b)、较低浓度106 cfu mL-1(c)以及空白对照(CK),以此研究解磷菌处理对不同土壤条件下有效磷含量的影响.结果显示:在不同浓度处理下,各解磷菌浓度对有效磷含量的影响差异不显著.相比较而言,北山阔叶林下土壤(Soil of north broadleaved forest,NBL)中b浓度处理促进效果较佳,南山针叶林下土壤(Soil of south coniferous forest,SC)和南方砖红壤(South latosol,SL)中c浓度处理表现较佳,而南山阔叶林下土壤(Soil of south broad-leaved forest,SBL)中有效磷含量在3个浓度梯度下影响差异不显著;不同解磷菌单菌及混合菌对各种土壤有效磷的影响总体上表现为混菌处理效果优于单菌,除SL土壤影响差异不显著外,3种森林土壤均表现出解磷菌处理显著提高土壤有效磷含量,其中在NBL土壤中,以BC、B、AC促进效果较佳,在SBL土壤中以B、BC、AC促进效果较佳,在SC土壤中以AC、ABC、BC促进效果较佳,在SL土壤中虽较空白处理差异不显著但以BC、A影响效果较佳.本研究表明,解有机磷菌与解无机磷菌的组合对提高土壤有效磷含量具有较好的促进作用.
The greenness （SPAD） of uneven-aged leaves of dominant species in the Castanopsis carlessi forest at different altitude gradients in Lingshishan National Forest Park, Fujian Province, China were measured by using po...
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The greenness （SPAD） of uneven-aged leaves of dominant species in the Castanopsis carlessi forest at different altitude gradients in Lingshishan National Forest Park, Fujian Province, China were measured by using portable chlorophyll meter SPAD-502. In addition, the correlation between SPAD value and the concentration of chlorophyll and foliar nitrogen was also investigated. Significant variations in SPAD values were found between the uneven-aged leaves of different dominant species and different altitude gradients. Regression analysis showed that SPAD value was significantly correlated with the concentration of chlorophyll and the content of foliar nitrogen, indicating that SPAD value could be indicators for foliar chlorophyll and nitrogen. It is suggested that SPAD meter is a useful tool for forest assessments in decision-making and operational nutrient management programs.
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