Variation in the calorific values of different plants organs in China

Abstract

The calorific value (CAL, KJ g–1) of different plant organs are important plant traits. Variation in CAL among different plant organs reflects the energy utilization and distribution strategy of plant. Here, we explored how the CAL of different plant organs varies at the species and regional level in relation to vegetation type (3697 forests samples, 430 grasslands samples, and 146 deserts samples). The results showed that, in the forests and grasslands, CAL significantly differed among the different organs and functional types of plants. The CAL of different organs in forests was ordered as: leaf (19.71 ± 1.82 KJ g–1) > branch (19.33 ± 1.32 KJ g–1) > trunk (19.09 ± 1.44 KJ g–1) > root (19.02 ± 1.11 KJ g–1). For forests, the CAL of plant organs, except for the leaves of trees and shrubs, increased with increasing latitude (P < 0.01). In comparison, the CAL in the roots of shrubs and herbs decreased with increasing longitude (P < 0.01). Through delineating systematic references of CAL among different plant organs, our findings provide key parameters to improve estimates of biomass energy at regional and global scales.

Study of energetic properties of different tree organs in six Olea europaea L. cultivars

“…The difference in calorific values in olive trees between above- and belowground organs, suggests that roots had lower calorific value; previous studies on other species 9 , 10 have shown that differences among several fractions are higher in aboveground organs (leaf, branch, and trunk) than in underground organs (root). The calorific value of the roots is generally lower with respect to organs photosynthetically active as leaves and shoots.…”

“…The calorific value of the roots is generally lower with respect to organs photosynthetically active as leaves and shoots. Roots, besides being devoted to absorbing water and nutrients from the soil have to guarantee energy to sustain the growth of the other organs of the plant and for this function their content in starch, fats, crude proteins and other substances is higher than in other organs of the trees 10 so the calorific values are relatively lower. Moreover the calorific value is connected to the lignin content 39 and likely in the root the lignin content is low; further analysis is necessary.…”

“…The residues of agricultural industry are one of the major sources of biomass, and studies aimed to understand the energetic characteristics of biomass, in particular pellet, are considerably increasing in recent years 6 – 8 . Many researchers have evaluated the heating value of different wood species 8 but only few are the studies on fruit trees species that focus on the energy content of the various tree organs as affected by the genetic traits 9 , 10 . Plant organs (leaves, branches and roots) are characterized by different morphological functional traits, furthermore trees adopt different strategies to distribute carbohydrates, thus energy, in the different organs 9 .…”

Duckweeds as Promising Food Feedstocks Globally

“…The energy/calorific value of duckweed was 1-19 KJ.g -1 . This value is related to the photosynthetic capacity of the plant and its nutritional status [93]. Besides, the plant type, organs, and position in the forest influence the energy value of the plant [93].…”

Evaluation of the calorific values of wastes from some tropical wood species

“…The solid fuels contain some moisture as free water in large pores and bound water inside of cell wall. Solid wood fuel suppliers require average moisture content below 20% for firewood (Marafon et al 2019, Yan et al 2018 and 10-12% for other wood fuel products like pellets, briquettes, chips, sawdust, etc. The dependency of the calorific power on the sample moisture content was evaluated for the low and high calorific value obtained for Acajou and Guaiac, respectively ( Figure 6).…”