Search Results (4)

Plastic film-bottomed treatment (FBT) is a critical agricultural practice in arid regions, aimed at enhancing crop productivity by improving soil moisture retention and nutrient availability. However, the effects of different depths of film-bottomed treatment (DFBT) on nitrogen (N) absorption and translocation in spring wheat remain inadequately understood. We conducted a field experiment on sandy soil to investigate the effects of different DFBT depths (60, 70, 80, 90, and 100 cm) and on total N absorption amount (TNAA), total N translocation amount (TNTA) in all nutritive organs, grain nitrogen content (GN), and grain yield (GY). Morphological measurements included GY, GN, TNAA, and TNTA in the stem, sheath, leaf, spike axis, kernel husk (SAKH), and culm. The results showed that FBT significantly reduced soil moisture loss, with the 100 cm depth reducing soil leakage by 59.6% (p < 0.001). At the flowering stage, nitrogen derived from fertilizer (NDF) and soil nitrogen (NDS) were significantly higher at the 80 cm depth (p < 0.001). At maturity, the total nitrogen absorption amount (TNAA) and translocation amount (TNTA) in the main stem and across nutrient organs were significantly higher under the 80 cm DFBT (p < 0.001), leading to improved nitrogen use efficiency. The correlation between TNTA and GN was strongest at 80 cm (p < 0.001). Grain yield (GY) and GN were optimized at intermediate depths, particularly at 80 cm, suggesting this depth provides an optimal balance between water retention and drainage efficiency. These findings underscore the importance of optimizing DFBT depth, particularly at 80 cm, to achieve enhanced water retention, efficient nitrogen utilization, and improved crop productivity in arid agricultural systems. This research provides critical insights into sustainable agricultural practices under water-limited conditions, offering practical guidance for improving food security in arid regions. Full article

The “leafing intensity premium” hypothesis proposes that leaf size results from natural selection acting on different leafing intensities, i.e., the number of leaves per unit shoot volume or mass. The scaling relationships among various above-ground functional traits in the context of this hypothesis are important for understanding plant growth and ecology. Yet, they have not been sufficiently studied. In this study, we selected four bamboo species of the genus Indocalamus Nakai and measured the total leaf fresh mass per culm, total non-leaf above-ground fresh mass, total number of leaves per culm, and above-ground culm height of 90 culms from each species. These data were used to calculate leafing intensity (i.e., the total number of leaves per culm divided by the total non-leaf above-ground fresh mass) and mean leaf fresh mass per culm (i.e., the total leaf fresh mass per culm divided by the total number of leaves per culm). Reduced major axis regression protocols were then used to determine the scaling relationships among the various above-ground functional traits and leafing intensity. Among the four species, three exhibited an isometric (one-to-one) relationship between the total leaf fresh mass per culm and the total non-leaf above-ground fresh mass, whereas one species (Indocalamus pumilus) exhibited an allometric (not one-to-one) relationship. A negative isometric relationship was found between the mean leaf fresh mass per culm and the leafing intensity for one species (Indocalamus pedalis), whereas three negative allometric relationships between mean leaf fresh mass per culm and leafing intensity were observed for the other three species and the pooled data. An exploration of the alternative definitions of “leafing intensity” showed that the total number of leaves per culm divided by the above-ground culm height is superior because it facilitates the non-destructive calculation of leafing intensity for Indocalamus species. These results not only confirm the leafing intensity premium hypothesis for bamboo species but also highlight the interconnected scaling relationships among different functional traits, thereby contributing to our understanding of the ecological and evolutionary significance of leaf size variation and biomass investment strategies. Full article

In this paper, we present the morphology, taxonomy, anatomy, and palynology of Arundo donax. A detailed morphological description and illustrations of the species are provided, along with information about the identification, distribution, the specimens examined, habitat and ecology, the International Union for Conservation of Nature (IUCN) conservation assessment, phenology, etymology, vernacular name, and uses. The species can be distinguished by its large, tall rhizomatous perennial reed; cauline leaves; an open, large, plumose panicle inflorescence; subequal glumes as long as the spikelets; glabrous rachilla; all bisexual florets; and a lemma with a straight awn and with long white hairs outside below the middle part. In this study, two names were lectotypified: Arundo bifaria and A. bengalensis, which are synonyms of A. donax. The culm internodes in the transverse section have numerous vascular bundles scattered in the ground tissue, and the parenchyma cells have significantly lignified cell walls. Vascular bundles are composed of phloem and xylem and are enclosed in a continuous sclerenchymatous bundle sheath. The chloroplasts in the transverse section of the leaf blades are found only in the mesophyll cells but are absent in the bundle sheath cells, which indicates that it is a C3 grass. The leaves have stomata on both surfaces and are confined to the intercostal zones. The stomata are typically paracytic, with two lateral subsidiary cells placed parallel to the guard cells. The stomatal density is higher on the abaxial surface [450–839/mm² (606.83 ± 72.71)] relative to the adaxial surface [286–587/mm² (441.27 ± 50.72)]. The pollen grains are spheroidal or subspheroidal [polar axis length/equatorial axis length ratio (P/E ratio) = 0.89–1.16 (1.02 ± 0.07)] with a single pore surrounded by a faint annulus, and the exine sculpturing is granular. Full article

Bamboo forest is a special forest type, and its aboveground biomass (AGB) is a key indicator of its carbon sequestration capacity and ecosystem productivity. Due to its complex canopy structure and particular growth pattern, the AGBs of individual bamboos that were estimated using traditional remotely sensed data are of relatively low accuracy. In recent years, the point cloud data scanned by terrestrial laser scanners (TLS) offer the possibility for more accurate estimations of bamboo AGB. However, bamboo culms tend to have various bending degrees during the growth process, which causes the AGB estimated on culm height (H) to be generally less than the true value. In this paper, taking one sample plot of the Moso bamboo forest in Hutou Village, Chongqing, China as the study site, we employed a TLS to acquire the point cloud data. The layer-wise distance discrimination method was first developed to accurately segment individual bamboos from the dense stand. Next, the diameter at breast height (DBH) and culm length (L) of an individual bamboo were precisely extracted by fitting the cross-section circle and constructing the longitudinal axis of the bamboo culm, respectively. Lastly, the AGBs of the Moso bamboos in the study site were separately calculated using the allometric equations with the DBH and L as predictor variables. As results, the precision of the complete bamboo segmentation was 90.4%; the absolute error ($AE$) of the extracted DBHs ranged from −1.22 cm to 0.88 cm ($R^2$ = 0.93, $RMSE$ = 0.40 cm); the $AE$ of the extracted Hs varied from –0.77 m to 1.02 m ($R^2$ = 0.91, $RMSE$ = 0.45 m); and the $AE$ of the extracted Ls varied from −1.08 m to 0.77 m ($R^2$ = 0.95, $RMSE$ = 0.23 m). The total estimated AGB of the Moso bamboos in the sample plot increased by 2.85%, from 680.40 kg on H to 696.36 kg on L. These measurements demonstrated the unique benefits of the TLS-acquired point cloud in characterizing the structural parameters of Moso bamboos and estimating their AGBs with high accuracy. Full article