Is Mass-based Metabolism Rate Proportional to Surface Area in Plant Leaves? A Data Re-analysis

We re-analyzed two large published databases on leaf traits of plant species from seven different biomes, and determined the scaling relationship between leaf metabolism rate （mass-based photosynthesis capacity, Amass, and mass-based dark respiration, Rdmass） and specific leaf area （SLA） across biomes, using a standardized major axis （SMA） method. Overall pooled data produced a scaling exponent of 1.33 for the relationship between Amass and SLA, significantly larger than 1.0; and 1.04 between Rdmass and SLA. The scaling exponent of the relationship between Amass and SLA ranged between 1.23 （in tropical forest） and 1.66 （in alpine biome）, and it was significantly larger in alpine （1.66） and grass/meadow （1.52） biomes than in tropical forest （1.23） and wetland （1.27）. The exponent of the relationship between Rdmass and SLA, however, was much smaller in wetland （1.05） than in temperate forest （1.29） and tropical rainforest （1.65）. In general, the predicated universal scaling relationship that the mass-based metabolism rate should be proportional to surface area in organisms is not applicable at the leaf-level in plants. Rather, the large slope difference of the relationship between leaf metabolism rate and SLA found among biomes indicates that the strength of the selective forces driving the scaling relationship is different among the biomes. The result basically suggests the importance of increasing SLA to plant carbon gain in stressful environments and to carbon loss in favorable habitats, and therefore has an important implication for survival strategies of plants in different biomes.

Biotransformation of soy whey into a novel functional beverage by Cordyceps militaris SN-18

Soy whey,a liquid nutritional by-product of soybean manufacture,is rich in proteins,oligosaccharides and isoflavones.Soy whey can be used to produce functional beverages,instead of discarding it as a waste.In this study,unfermented soy whey(USW)and Cordyceps militaris SN-18-fermented soy whey(FSW)were investigated and compared for their physicochemical and functional properties by high performance liquid chromatography(HPLC)and DNA damage assay.Results show that C.militaris SN-18 fermentation could increase the contents of essential amino acids,total phenolic and flavonoid and isoflavone aglycones and eliminate the oligosaccharides in soy whey.Furthermore,C.militaris SN-18 could significantly enhance the ABTS radical scavenging ability,reducing power and ferric reducing power of soy whey,and its fermented products could prominently attenuate Fenton reaction-induced DNA damage.These findings indicate that soy whey can potentially be converted into a novel soy functional beverage by C.militaris SN-18 fermentation.