摘要
探讨无患子(Sapindus mukorossi Gaertn.)生长和光合作用对酸性土壤胁迫的响应机制,为其高效种植提供理论依据。采用随机区组实验设计,以重庆市紫色土不同程度酸性区(pH分别为7.56、5.65、4.41)3年生无患子幼树为研究对象,分析紫色土酸性对无患子幼树生长、叶性状指标和光合作用的影响。结果表明:中性区土壤速效氮(AN)、速效磷(AP)含量极显著低于酸性区,中性区叶片全氮(TN)、全钾(TK)含量极显著高于酸性区(P<0.01)。与中性区相比,酸性区幼树的株高、净光合速率(Pn)、总叶绿素(Chls)、叶绿素a(Chl a)、类胡萝卜素(Cars)含量、叶绿素a/b(Chl a/b)比值极显著减小(P<0.01),最大光化学效率(Fv/Fm)和非光化学淬灭系数(qN)显著减少(P<0.05),而叶绿素b(Chl b)含量和叶绿素/类胡萝卜素(Chls/Cars)比值极显著增加(P<0.01),冠幅、电子传递效率(ETR)、光化学淬灭系数(qP)、实际原初光能捕获效率(Y(Ⅱ))显著增大(P<0.05);与中性区相比,强酸性区叶片光饱和点(LSP)极显著下降(P<0.01),表观量子效率(AQY)、光补偿点(LCP)、暗呼吸速率(Rd)最高,弱酸性区最低;弱酸性区的地径、比叶面积(SLA)、叶面积(LA)、气孔导度(Gs)和蒸腾速率(Tr)在3个试验区中均最大,且显著高于强酸性区(P<0.05)。紫色土酸性通过影响土壤养分转化、根系吸收能力,显著降低了酸性区无患子幼树的光合能力,而弱酸性区幼树叶片通过增大光能捕获面积,提高PSⅡ光合电子传递速率和光能捕获效率,降低有机物质消耗,表现出较强的生态适应性。因此,无患子在重庆紫色土区种植的pH适宜范围为5.5-7.5,而在pH值低于5.5的紫色土种植时,生长发育不良。
Sapindus mukorossi Gaertn.(Indian soapberry) is an important tree species with many economic and ecological applications. In recent years it has been widely planted in poor mountainous areas of southwest China in association with forest restoration programs. At the same time, purple soil acidification due to excess use of fertilizers has increased in the southwest hilly areas and this has impacted the growth of S. mukorossi. Photosynthesis leads to creation of plant organic matter which tends to accumulate, but when photosynthetic capacity declines there are progressive impacts on soil quality. Studying the responses of photosynthesis and growth of S. mukorossi to acid soil stress will provide a theoretical basis for effective planting. We conducted soil acid stress experiments using randomized block experimental design in a purple soil acidic region of Chongqing. Three-year-old saplings were examined growing in soils having different degrees of acidity(pH 4.4, 5.6 and 7.6). The effects of soil acidity on growth, leaf traits and photosynthesis were analyzed. The results showed that the contents of soil available nitrogen(AN) and available phosphorus(AP) in the neutral zone were significantly lower than those in the acidic zone, and the contents of total nitrogen(TN) and total potassium(TK) in the leaves of the neutral zone were significantly higher than those in the acidic zone(P<0.01). Compared with neutral soils, in acidic regions the height of saplings, net photosynthetic rate of leaves(Pn), total chlorophyll content(Chls), chlorophyll a(Chl a), carotenoid(Cars), and ratio of chlorophyll a/chlorophyll b(Chl a/b) were significantly lower(P<0.01). The maximum photochemical efficiency of PSⅡ(Fv/Fm) and the PSⅡnon-photochemical fluorescence quenching coefficient(qN) were also lower(P<0.05). In addition, the content of chlorophyll b(Chl b) and the ratio of chlorophyll/carotenoid(Chls/Cars) were significantly higher(P<0.01). Crown width, PSⅡelectron transfer rate(ETR), PSⅡ photochemical fluorescence quenching coefficient(qP) and actual primary light capture efficiency(Y(II)) also increased(P<0.05). In strongly acidic soil, the light saturation point(LSP) of leaves was significantly lower(P<0.01), while the apparent quantum yield(AQY), light compensation point(LCP) and dark respiration(Rd) were the highest. AQY, LCP and Rd were lowest in the weakly acidic soil. Ground diameter, specific leaf area(SLA), leaf area(LA), stomatal conductance(Gs)and transpiration rate(Tr)of the experimental saplings in the weakly acidic soil were the highest among the three experimental soils, and significantly higher than in the strongly acidic soil(P<0.05). The acidity of purple soil significantly reduced the photosynthetic capacity of S. mukorossi. in acidic region by affecting soil nutrient transformation and root absorption capacity. The saplings in weak acidic region showed strong ecological adaptability owing to increasing light energy capture area, increasing photosynthetic electron transfer rate and light energy capture efficiency of PS II, and reducing organic matter consumption. We conclude that the suitable range of pH values for planting Sapindus mukorossi in purple soil regions of Chongqing was 5.5-7.5, while growth was poor when planted in purple soil with pH less than 5.5.
作者
田秋玲
乐佳兴
吴焦焦
张文
高岚
钱春
刘芸
TIAN Qiuling;YUE Jiaxing;WU Jiaojiao;ZHANG Wen;GAO Lan;QIAN Chun;LIU Yun(College of Resources and Environment,Southwest University,Chongqing 400700,China;College of Horticulture and Landscape,Southwest University,Chongqing 400700,China)
出处
《生态学报》
CAS
CSCD
北大核心
2020年第11期3756-3763,共8页
Acta Ecologica Sinica
基金
中央财政林业科技推广示范项目(渝林科推【2016-04号】)
国家自然科学基金(31370602)
重庆市社会事业与民生保障科技创新专项项目(cstc2017shms-xdny80062)。
关键词
无患子
紫色土酸性
生长
光合特性
叶性状
Sapindus mukorossi Gaertn.
purple soil acidity
growth
photosynthetic characteristics
leaf trait
