A field and glasshouse experiment was conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on growth and leaf chlorophyll content in soybean. The treatments consisted of B. japonicu...A field and glasshouse experiment was conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on growth and leaf chlorophyll content in soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kgP·ha-1. Both treatments were replicated four times in a split plot design. The following parameters were measured: plant height (cm), number leaves per plant, number of days to 50% flowering, number of days to 50% pod formation, stem girth and leaf area (LA). Results showed that inoculation with B. japonicum significantly increased plant height, number of leaves, leaf chlorophyll content, stem girth, leaf area (LA) and leaf area index (LAI). However, Phosphorus supplementation had significant effects in some parameters measured. The use of effective strain of B. japonicum and phosphorus supplementation was an efficient way of enhancing the growth of soybean.展开更多
Aims UV-B radiation is known to affect plant physiology and growth rate in ways that can influence community species composition and structure.Nevertheless,comparatively little is known about how UV-B radiation induce...Aims UV-B radiation is known to affect plant physiology and growth rate in ways that can influence community species composition and structure.Nevertheless,comparatively little is known about how UV-B radiation induced changes in the performance of individual species cascades to affect overall community properties.Because foliage leaves are primarily responsible for photosynthesis and carbon gain and are the major organ that senses and responds to UV-B radiation,we hypothesized that,under reduced UV-B radia-tion,species with larger leaf areas per plant would manifest higher growth rates and hence tend to improve their community status compared to species with smaller leaf areas per plant in herba-ceous plant communities.Methods We tested this hypothesis by examining plant traits(leaf area per plant and plant height),plant growth rate(aboveground biomass per plant and plant biomass per area)and community status(spe-cies within-community relative biomass)for 19 common species in a two-year field experiment in an alpine meadow on Tibetan Plateau.Important findings Aboveground biomass per plant,as well as per area,progressively increased in a 39%reduced(relative to ambient)UV-B treatment dur-ing the experimental period.At the second year,11 out of 19 species significantly or marginally significantly increased their plant height,leaf area per plant and aboveground biomass per plant.No species was negatively affected by reducing UV-B.As hypothesized,the increase in aboveground biomass per plant increased with increasing leaf area per plant,as indicated by cross-species regression analysis.Moreover,the change in species within-community status increased with increasing leaf area per plant.Our study demonstrates that UV-B radiation has differential effects on plant growth rate across species and hence significantly affects species composition and plant commu-nity structure.We suggest that UV-B radiation is an ecological factor structuring plant communities particularly in alpine and polar areas.展开更多
文摘以湛江市6种园林植物常绿乔木小叶榕(Ficus concinna)和人面子(Dracontomelon duperreanum),常绿灌木龙船花(Ixora chinensis)和朱槿(Hibiscus rosa-sinensis)以及落叶乔木大花紫薇(Lagerstroemia speciosa)和黄葛榕(Ficus virens)为研究对象,探讨叶绿素仪(CCM)在研究植物NOx吸收能力中的应用。研究结果表明:1)6种植物的叶片CCI值与全氮含量均呈显著的正相关,朱槿和人面子表现出最好的线性相关(R2=0.70,P<0.001;R2=0.74,P<0.001),CCI值可以用于叶片氮含量的预测。2)植物可以响应不同浓度的NOX而表现出叶片氮含量的差异,各树种的叶片CCI值均为污染区显著高于清洁区,与叶片实测氮含量呈相同的变化趋势。3)CCI值在植物生活型间并不存在显著差异,宜在物种水平上进行研究;CCI值同时受叶面积、叶片含水率和叶比重(Leaf mass per area,LMA)等因素的影响。利用CCI值可以快速、无损地测定叶片在污染区和清洁区不同NOX浓度下叶片全氮的相对含量,从而判断不同植物的NOX相对吸收能力,但这一方法的准确实施,不仅需要更大的样本建立精准的模型,也需要更加科学、合理的取样,更为关键的是污染区和清洁区的CCI差值应建立一个统一的转换尺度。
文摘A field and glasshouse experiment was conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on growth and leaf chlorophyll content in soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kgP·ha-1. Both treatments were replicated four times in a split plot design. The following parameters were measured: plant height (cm), number leaves per plant, number of days to 50% flowering, number of days to 50% pod formation, stem girth and leaf area (LA). Results showed that inoculation with B. japonicum significantly increased plant height, number of leaves, leaf chlorophyll content, stem girth, leaf area (LA) and leaf area index (LAI). However, Phosphorus supplementation had significant effects in some parameters measured. The use of effective strain of B. japonicum and phosphorus supplementation was an efficient way of enhancing the growth of soybean.
基金This study was supported by National Science Foundation of China(31530007 and 31325004).
文摘Aims UV-B radiation is known to affect plant physiology and growth rate in ways that can influence community species composition and structure.Nevertheless,comparatively little is known about how UV-B radiation induced changes in the performance of individual species cascades to affect overall community properties.Because foliage leaves are primarily responsible for photosynthesis and carbon gain and are the major organ that senses and responds to UV-B radiation,we hypothesized that,under reduced UV-B radia-tion,species with larger leaf areas per plant would manifest higher growth rates and hence tend to improve their community status compared to species with smaller leaf areas per plant in herba-ceous plant communities.Methods We tested this hypothesis by examining plant traits(leaf area per plant and plant height),plant growth rate(aboveground biomass per plant and plant biomass per area)and community status(spe-cies within-community relative biomass)for 19 common species in a two-year field experiment in an alpine meadow on Tibetan Plateau.Important findings Aboveground biomass per plant,as well as per area,progressively increased in a 39%reduced(relative to ambient)UV-B treatment dur-ing the experimental period.At the second year,11 out of 19 species significantly or marginally significantly increased their plant height,leaf area per plant and aboveground biomass per plant.No species was negatively affected by reducing UV-B.As hypothesized,the increase in aboveground biomass per plant increased with increasing leaf area per plant,as indicated by cross-species regression analysis.Moreover,the change in species within-community status increased with increasing leaf area per plant.Our study demonstrates that UV-B radiation has differential effects on plant growth rate across species and hence significantly affects species composition and plant commu-nity structure.We suggest that UV-B radiation is an ecological factor structuring plant communities particularly in alpine and polar areas.
