Foliar concentrations of starch and major nutrients N, P, K, Ca, and Mg along with specific leaf weight (SLW) were determined in the potato (Solanun tuberosum L.) cvs "Denali", "Norland "'and &...Foliar concentrations of starch and major nutrients N, P, K, Ca, and Mg along with specific leaf weight (SLW) were determined in the potato (Solanun tuberosum L.) cvs "Denali", "Norland "'and "Russet Burbank" grown for 35 days under the CO2 concentrations of 500, 1 000, 1 500 and 2 000 mol mol-1 at both 16 and 20℃ air temperature. The starch concentration, pooled from the three cultivars, increased with increasing CO2 concentration at both 16 and 20℃,, and was consistently higher at 16℃ than at 20℃. The SLW (g m-2) was positively related to the foliar starch concentration on the basis of leaf area or dry weight. The concentrations of N, P, Ca, and Mg in leaves were negatively related to starch concentration under 14% starch on a dry weight basis. Above 14%, there was no significant relationship between nutrient and starch concentrations . The similar patterns were seen when the SLW and nutrient concentrations were expressed on a starch-free basis. In contrast, the leaf concentration of K was not closely related to the starch concentration. The results indicated that the changes in SLW and concentrations of N, P, Ca, and Mg in potato leaves only partially resulted from the changed starch concentration.展开更多
Leaf size varies conspicuously within and among species under different environments.However,it is unclear how leaf size would change with elevation,whether there is a general elevational pattern,and what determines t...Leaf size varies conspicuously within and among species under different environments.However,it is unclear how leaf size would change with elevation,whether there is a general elevational pattern,and what determines the altitudinal variation of leaf size.We thus aimed to address these questions by focusing on the broad-leaved herbaceous species at high altitudes on the northeastern Qinghai-Tibetan Plateau.We measured the leaf size,leaf length,leaf width and leaf mass per area for 39 broad-leaved herbaceous species inhabited in the open areas along two mountain slopes from 3200 to 4400 m at the Lenglongling and the Daban Mountain,the northeastern Qinghai-Tibetan Plateau.We analyzed the altitudinal patterns in leaf size in relation to leaf inclination and leaf surface features,and applied a leaf energy balance model to discuss the underlying mechanisms.Leaf size decreased significantly at higher altitudes.The altitudinal reduction of leaf size was mainly attributed to the reduction of leaf length,and differed in different species,and in leaves with different inclination and leaf surface features.A leaf energy balance model with local environmental measurements demonstrates that leaf temperature tracks air temperature more closely in small than in large leaves,and that the leaf-size impact is stronger at higher latitudes.Based on the observational findings,we propose that the distribution upper-limit for broad-leaved herbaceous species would be at an elevation of about 5400 m on the northeastern Qinghai-Tibetan Plateau.展开更多
文摘Foliar concentrations of starch and major nutrients N, P, K, Ca, and Mg along with specific leaf weight (SLW) were determined in the potato (Solanun tuberosum L.) cvs "Denali", "Norland "'and "Russet Burbank" grown for 35 days under the CO2 concentrations of 500, 1 000, 1 500 and 2 000 mol mol-1 at both 16 and 20℃ air temperature. The starch concentration, pooled from the three cultivars, increased with increasing CO2 concentration at both 16 and 20℃,, and was consistently higher at 16℃ than at 20℃. The SLW (g m-2) was positively related to the foliar starch concentration on the basis of leaf area or dry weight. The concentrations of N, P, Ca, and Mg in leaves were negatively related to starch concentration under 14% starch on a dry weight basis. Above 14%, there was no significant relationship between nutrient and starch concentrations . The similar patterns were seen when the SLW and nutrient concentrations were expressed on a starch-free basis. In contrast, the leaf concentration of K was not closely related to the starch concentration. The results indicated that the changes in SLW and concentrations of N, P, Ca, and Mg in potato leaves only partially resulted from the changed starch concentration.
基金The study was supported by a grant“Ecological processes and their climatic consequences of carbon,nitrogen and water cycles on the Qinghai-Tibetan Plateau.”from NSFC,and a project funding“effects of westerly-monsoon interactions on carbon and nitrogen cycles”provided by MOST.
文摘Leaf size varies conspicuously within and among species under different environments.However,it is unclear how leaf size would change with elevation,whether there is a general elevational pattern,and what determines the altitudinal variation of leaf size.We thus aimed to address these questions by focusing on the broad-leaved herbaceous species at high altitudes on the northeastern Qinghai-Tibetan Plateau.We measured the leaf size,leaf length,leaf width and leaf mass per area for 39 broad-leaved herbaceous species inhabited in the open areas along two mountain slopes from 3200 to 4400 m at the Lenglongling and the Daban Mountain,the northeastern Qinghai-Tibetan Plateau.We analyzed the altitudinal patterns in leaf size in relation to leaf inclination and leaf surface features,and applied a leaf energy balance model to discuss the underlying mechanisms.Leaf size decreased significantly at higher altitudes.The altitudinal reduction of leaf size was mainly attributed to the reduction of leaf length,and differed in different species,and in leaves with different inclination and leaf surface features.A leaf energy balance model with local environmental measurements demonstrates that leaf temperature tracks air temperature more closely in small than in large leaves,and that the leaf-size impact is stronger at higher latitudes.Based on the observational findings,we propose that the distribution upper-limit for broad-leaved herbaceous species would be at an elevation of about 5400 m on the northeastern Qinghai-Tibetan Plateau.
