Higher Leaf Biomass Research Articles

Relationship between foliar polycyclic aromatic hydrocarbons (PAHs) concentrations and plant traits: Intracanopy variability for a broadleaf species in an urban environment

The emission of potentially harmful compounds, including polycyclic aromatic hydrocarbons (PAHs), and the resulting air pollution is a serious problem in modern cities. It is therefore important to develop mitigation strategies, such as “smart” planting of trees that act as sinks for PAHs. However, the intra-individual (within-tree) variability in leaf PAH concentrations remains unknown. In this paper, we studied 15 ornamental apple trees (Malus × moerlandsii ‘Profusion’) growing on a main street in a medium-sized city in Galicia (NW Spain). We determined the PAH concentrations at 12 canopy positions in each tree (2 orientations and 2 distances from the trunk at 3 heights), measured various ecological traits (specific leaf area [SLA], δ13C, stomatal density, fatty acid contents and leaf hairiness) and analyzed the variability in traits within the canopy in relation to PAH concentrations. We observed high intra-individual variability in the PAH concentrations and the leaf traits. Statistical analyses revealed that leaf height was the main source of variability both in the PAH concentrations and in the traits, mainly due to the leaf morphology, particularly to the SLA. Therefore, the ideal vegetation to remove PAHs would be high leaf biomass trees, not too tall and with a high proportion of shade leaves.

Augmentation of plant biomass productivity using epigeic earthworm Perionyx excavatus and Eisenia fetida as soil nutrient facilitators

With the increasing demand for organic food production, the earthworm is used as a soil nutrient facilitator. The present study was conducted to assess the effect of epigeic earthworms Perionyx excavatus and Eisenia. fetida on soil nutrients and the consequent improvement of biomass productivity and yield of Capsicum chinense Jacq and Zea mays L. The experiment was conducted in 5 L and 15 L capacity plastic pots for C. chinense and Z. mays with 150 g and 300 g of half-decomposed cow dung, respectively. It was observed that the weekly harvest rate of ripened chili was 17.59 g, 13.91 g, and 9.24 g in P. excavatus, control, and E. fetida pot showing 26.49% higher in P. excavatus. Also, the total kernel count per corn was significantly different (F(2, 9) = 37.78, p < 0.05), with the highest kernel present in P. excavatus(333.5 ± 13.5), followed by E. fetida(261.5 ± 16.5) and control (235 ± 22). The impact of P. excavatus was more perceptible in C. chinense, indicated by higher leaf biomass (69.16%), root length (30.14%), and fruit harvest (71.03%). However, the effect of E. fetida was noticed more in Z. mays (stem length, 19.24%, stem biomass, 14.39%, root biomass, 20.9%, kernel count, 41.91%, and kernel weight, 95.07%). Enhanced plant productivity was also supported by an increasing soil nutrient turnover in organic carbon (OC) (25.76% and 23.4%), Phosphorus (P) (31.03% and 25.67%), and Potassium (K) (41.67% and 12.26) in P. excavatus and E. fetida worked soil respectively. The findings indicate that earthworms have a notable impact on plant biomass productivity by promoting the mineralization of soil nutrients and imply on possibility of organic cultivation of seasonal vegetables without using synthetic fertilizers.

Assessing the Impact of Altered Clay Mineral and Red Mud Derivatives on the Characteristics of Mustard (B. juncea) and the Soil Arsenic Content

A pot experiment was conducted during the winter season (rabi) of 2020-21 at ICAR-Indian Agricultural Research Institute, New Delhi. Indian mustard (Brassica juncea) was cultivated to investigate the impact of modified clay mineral (Bentonite) and Red mud on yield characteristics and total arsenic content in the soil. The main objective was to examine how the application of modified clay mineral and red mud (Fe-exchanged bentonite, Dimethyl sulfoxide-intercalated bentonite, and Iron-exchanged red mud) would affect the yield attributes of Indian mustard. The initial soil's total arsenic content was 16.2 mg kg-1. The results revealed that all the mentioned treatments led to a significant increase in leaf biomass and root volume compared to the control pot. Significantly, highest leaf biomass (g pot-1) was recorded in Fe-exchanged bentonite (4.10 g pot-1) followed by Dimethyl sulfoxide-intercalated bentonite (4.00 g pot-1), and Iron-exchanged redmud (3.93 g pot-1) respectively at the rate of 5.00 g product per kg soil. The highest root volume (6.6 cm2) was observed in soil treated with 5.00 g kg-1 of Fe-exchanged bentonite. Dimethyl sulfoxide-intercalated bentonite, and Iron-exchanged red mud also showed positive effects but to a lesser extent. total As content in contaminated soil was thoroughly investigated, and the results revealed that these clays did not exert a significant influence on the total As content under the given application rates.

Nocardiopsis lucentensis and thiourea co-application mitigates arsenic stress through enhanced antioxidant metabolism and lignin accumulation in rice

Arsenic (As) is a group-1 carcinogenic metalloid that threatens global food safety and security, primarily via its phytotoxicity in the staple crop rice. In the present study, ThioAC, the co-application of thiourea (TU, a non-physiological redox regulator) and N. lucentensis (Act, an As-detoxifying actinobacteria), was evaluated as a low-cost approach for alleviating As(III) toxicity in rice. To this end, we phenotyped rice seedlings subjected to 400 mg kg−1 As(III) with/without TU, Act or ThioAC and analyzed their redox status. Under As-stress conditions, ThioAC treatment stabilized photosynthetic performance, as indicated by 78 % higher total chlorophyll accumulation and 81 % higher leaf biomass, compared with those of As-stressed plants. Further, ThioAC improved root lignin levels (2.08-fold) by activating the key enzymes of lignin biosynthesis under As-stress. The extent of reduction in total As under ThioAC (36 %) was significantly higher than TU (26 %) and Act (12 %), compared to those of As-alone treatment, indicating their synergistic interaction. The supplementation of TU and Act activated enzymatic and non-enzymatic antioxidant systems, respectively, with a preference for young (TU) and old (Act) leaves. Additionally, ThioAC activated enzymatic antioxidants, specifically GR (∼3-fold), in a leaf-age specific manner and suppressed ROS-producing enzymes to near-control levels. This coincided with 2-fold higher induction of polyphenols and metallothionins in ThioAC-supplemented plants, resulting in improved antioxidant defence against As-stress. Thus, our findings highlighted ThioAC application as a robust, cost-effective ameliorative strategy, for achieving As-stress mitigation in a sustainable manner.

Root Morphology and Biomass Allocation of 50 Annual Ephemeral Species in Relation to Two Soil Condition.

Different organ morphologies determine the manner in which plants acquire resources, and the proportion of biomass of each organ is a critical driving force for organs to function in the future. Regrettably, we still lack a comprehensive understanding of root traits and seedling biomass allocation. Accordingly, we investigated and collected the seedling root morphological traits and biomass allocation of 50 annual ephemeral species to clarify the adaptation to environment. The findings of this study showed that there was a significantly negative correlation between root tissue density (RTD) and root diameter (RD) (p < 0.05), which did not conform to the hypothesis of the one-dimensional root economics spectrum (RES). On this basis, we divided 50 plant species into those rooted in dense or gravelly sand (DGS) or loose sand (LS) groups according to two soil conditions to determine the differences in root strategy and plant strategy between the two groups of plants. Our study revealed that the species rooting DGS tend to adopt a high penetration root strategy. However, the species rooting LS adopt high resource acquisition efficiency. At the whole-plant level, 50 species of ephemerals were distributed along the resource acquisition and conservation axis. Species rooting DGS tend to adopt the conservation strategy of high stem biomass fraction and low resource acquisition efficiency, while species rooting LS tend to adopt the acquisition strategy of high root and leaf biomass fraction and high resource acquisition efficiency. The research results provide a theoretical basis for the restoration and protection of vegetation in desert areas.

Influence of Varieties and Spacings on Growth, Biomass Yield and Nutritional Value of Corn Silage in Paddy Field

Abstract The objectives of the experiment were to determine plant spacing and variety to produce the suitable growth, yield components, biomass yield of field corn and nutritional value of corn silage in paddy field condition. The field experiment was conducted at the Lopburi Research Station, Khok Charoen district, Lopburi province, Thailand in 2018-2019 and was arranged in a split plot design in randomized complete block design (RCBD) with 4 replications. The main plot contained 3 plant spacings viz. 75×15, 75×20 and 75×25 cm and sub plot consisted of 5 field corn varieties (CP888, NS3, S7328, SW4452 and SW5). The results showed that wide spacing tended to produce higher ears per plant than narrow spacing. CP888 was the highest ears per plant variety. NS3 was the highest leaf/stem ratio variety. SW5 showed high leaf, stem and fresh biomass yield and it also produce ear yield closing to a high ear yield variety at 75×25 cm spacing. Moreover, SW5 also had high crude protein (CP) content, while plant spacing did not significantly affect acid detergent fiber (ADF), acid detergent lignin (ADL), ash, and lactic acid of corn silage. The widest spacing (75×25 cm) showed lower NDF than the narrowest spacing (75×15 cm). It was evident that SW5 and 75×25 cm spacing may be considered optimum for biomass yields without negatively affecting the corn silage quality. Keywords: Nutritional value, Paddy field, Plant spacing, Silage corn, Variety

Drumstick (Moringa oleifera) variation in biomass and total flavonoid content in Indonesia

Abstract. Ridwan, Hamim, Suharsono, Hidayati N, Gunawan I. 2021. Drumstick (Moringa oleifera) variation in biomass and total flavonoid content in Indonesia. Biodiversitas 22: 493-500. Utilization of a drumstick (Moringa oleifera Lam.) leaf has recently increased worldwide which consequently cause the increase in global demand. Indonesia, as a tropical country with large area, has a great potential to become a center for drumstick cultivation and leaf production. Drumstick distribution scattered in almost all of the islands of Indonesia has another potential for obtaining superior genotype variabilities. The aim of this study was to select the drumstick accessions from several islands in Indonesia with high leaf biomass production and flavonoid content. This experiment was carried out in the field using ten accessions of drumstick from ten islands in Indonesia, namely Sumatra, Java, Madura, Bali, Lombok, Sumbawa, Sumba, Kalimantan, Sulawesi, and Papua. Drumstick seeds were planted in polybags with a capacity of 10 kg and arranged using a randomized block design with three replications. The parameters observed were plant growth, biomass production, total flavonoid content, and antioxidant activity. The results of this study found that Sumatra accession was the accession which had the highest leaf biomass production in combination with the uppermost total flavonoid content and antioxidant activity compared to others. Sumatra accession is recommended as an excellent accession for cultivation with the aim of producing flavonoids.

RB961552 - Highly productive sugarcane cultivar with fast inter-row closure

Abstract: Sugarcane cultivar RB961552 was developed by the Sugarcane Breeding Program of the Federal University of Alagoas, a member university of RIDESA. It was selected for being highly productive, responsive to fertigation and for the high leaf biomass and excellent inter-row closure. It is resistant to brown and orange rust and moderately resistant to leaf scald and smut diseases.

Physiological Basis of Salt Stress Tolerance in a Landrace and a Commercial Variety of Sweet Pepper (Capsicum annuum L.).

Salt stress is one of the most impactful abiotic stresses that plants must cope with. Plants’ ability to tolerate salt stress relies on multiple mechanisms, which are associated with biomass and yield reductions. Sweet pepper is a salt-sensitive crop that in Mediterranean regions can be exposed to salt build-up in the root zone due to irrigation. Understanding the physiological mechanisms that plants activate to adapt to soil salinization is essential to develop breeding programs and agricultural practices that counteract this phenomenon and ultimately minimize yield reductions. With this aim, the physiological and productive performances of Quadrato D’Asti, a common commercial sweet pepper cultivar in Italy, and Cazzone Giallo, a landrace of the Campania region (Italy), were compared under different salt stress treatments. Quadrato D’Asti had higher tolerance to salt stress when compared to Cazzone Giallo in terms of yield, which was associated with higher leaf biomass vs. fruit ratio in the former. Ion accumulation and profiling between the two genoptypes revealed that Quadrato D’Asti was more efficient at excluding chloride from green tissues, allowing the maintenance of photosystem functionality under stress. In contrast, Cazzone Giallo seemed to compartmentalize most sodium in the stem. While sodium accumulation in the stems has been shown to protect shoots from sodium toxicity, in pepper and/or in the specific experimental conditions imposed, this strategy was less efficient than chloride exclusion for salt stress tolerance.

Effects of reciprocal hybridization on the quality of Solanum photeinocarpum

In order to explore whether reciprocal hybridization can be used to cultivate new varieties of wild vegetable, the experiment used two ecological types (farmland ecotype and mine ecotype) of Solanum photeinocarpum as the experimental material of reciprocal hybridization, and compared the difference of qualities of F1 hybrids and parents. The results showed that the biomass, contents of vitamin C, soluble sugar, total acid, and soluble solids of leaves and stems of the F1 hybrid plants were not significantly different. But the indicators of F1 hybrid were higher than the parents. Among them, mining male × farmland female F1 hybrids has the highest leaf biomass, vitamin C content and soluble sugar content. The highest leaf biomass, vitamin C content and soluble sugar content were increased by 13.70%, 65.90% and 117.26% respectively, compared with the farmland ecotype, and increased by 14.40%, 48.89% and 54.99% respectively, compared with the mine ecotype. It indicated that reciprocal hybridization can effectively increase the biomass and the content of nutrients including vitamin C of F1 hybrids and reciprocal hybridization can be used to get new species of Solanum photeinocarpum.

Biomass production of a young plantation of Moringa stenopetala (Baker f.) Cufod. and Moringa oleifera Lam. in southern Ethiopia

In May 2017, a plantation of Moringa stenopetala and Moringa oleifera was established in southern Ethiopia using a spacing of 1 × 1.5 m. The plantation was not artificially irrigated, and no fertilizers or pesticides have been applied. To assess the suitability of cultivation on the plantation, the average leaf biomass production and, secondarily, to evaluate the nutritional potential of both species, three harvests were carried out in November 2017, March 2018 and in November 2018. The leaf biomass was harvested in each trial from the same thirty trees. A principal objective of the study was to describe the suitability of Moringa stenopetala for cultivation in an intensive plantation and to compare these results with the results of cultivation of Moringa oleifera. The results show that in young plantations of M. stenopetala, dry matter biomass production could reach up to 2,824 kg/ha/year, while for M. oleifera, it could reach 6,060 kg/ha/year. One harvest of a M. oleifera plantation's (705 trees) total estimated leaf biomass would yield a one day proper calorie intake for 340 adult humans (irrespective of gender), while M. stenopetala would supply only 123 people, i.e., 1 ha of M. oleifera plantation would supply a one day proper calorie intake to 3,213 adults, while M. stenopetala would supply a one day proper calorie intake to 1,159 adults. Based on the evaluated data, M. oleifera is considered to be more suitable for (growing on) plantations in southern Ethiopia due to its pest resistance and high leaf biomass production.

Responses of seed germination and seedling growth of Cunninghamia lanceolata and Schima superba to different light intensities.

Light is a key factor affecting seed germination and seedling growth. In this study, seed germination and seedling growth of Cunninghamia lanceolata and Schima superba were compared under controlled conditions with five light treatments (100%, 60%, 40%, 15% and 5% of full sunlight). The results showed that light intensity significantly impacted seed germination and seedling growth of both species. With decreasing light intensity, the germination rate and germination index of C. lanceolata increased, while those of S. superba showed a trend which increased first and then decreased, with the maximum at 40% light intensity. The seedling survival rate of both species was 0 under full sunlight, while significantly decreased with decreasing light intensity from 60% to 5%. Root length, basal stem diameter and height showed a consistent trend with the change of light availability in both species. Root length significantly decreased, basal stem diameter and height increased first and then decreased with decreasing light intensity, with the minimum at 5% light intensity. With decreasing light intensity, root biomass, stem biomass, leaf biomass and total biomass of C. lanceolata seedlings declined, while high biomass accumulation of S. superba seedlings were observed in 15%-60% light intensities, and lowest at 5% light intensity. Biomass accumulation in each organ of S. superba seedlings was greater than that of C. lanceolata seedlings under the same light intensity. High stem biomass and leaf biomass, low root biomass and root to shoot ratio were a phenotypic response to low light intensity in C. lanceolata and S. superba seedlings grown under poor light condition. The growth of C. lanceolata is better under relatively high light intensity than S. superba. Whereas S. superba is moderately shade-tolerant at the seedling stage, thus is more suitable for planting under closed canopy.

Weed-competitive ability of a hybrid and an inbred rice cultivar in managing Ischaemum rugosum in dry-seeded rice

Ischaemum rugosum Salisb. commonly known as ribbed murainagrass is a problematic herbicide-resistant weed in directseeded rice systems. To evaluate the competitive ability of rice cultivars against I. rugosum, a study was established with two rice cultivars (Mestiso 21, a hybrid and IR 64, an inbred). These cultivars were sown at density of 4 plants per pot with four different densities of I. rugosum (0, 2, 4, and 8 plants pot(-1)). Across weed density levels, IR 64 had 14% lower while Mestiso 21 had 20% higher plant height than I. rugosum. In competition with eight I. rugosum plants per pot, Mestiso 21 had 17% higher plant height (85 cm) than of IR 64 (73 cm). Without competition, IR 64 had higher tiller number, leaf number, leaf area, and root biomass than Mestiso 21 while in competition with eight weed plants per pot, Mestiso 21 had higher leaf biomass (29%), stem biomass (13%), specific stem length (38%), panicle biomass (29%), florets number (41%), and florets biomass (36%) than IR 64. In comparison with control (no weed competition), weed densities of 2, 4, and 8 plants pot(-1) reduced the total rice biomasses and grain yields by 32, 42, and 50%; and 26, 46, and 56% for IR 64 and by 23, 37, and 45%; and 20, 28, and 42% for Mestiso 21, respectively. The Mestiso 21 reduced the I. rugosum plant height, number of tillers, leaf biomass, inflorescence biomass, root biomass, and total aboveground biomass by 16.3, 0.3, 22.1, 31.3, 21.8, and 22.7%, respectively, compared with IR 64. The results of this study suggest that the hybrid rice Mestiso 21 has a better competitive ability to suppress I. rugosum than IR 64 therefore can be used in an integrated weed management of problematic weeds in direct-seeded rice systems.

Germination and morphophysiology of passion fruit seedlings under salt water irrigation1

ABSTRACT The use of salt water in irrigation can reduce the growth and yield of agricultural crops. This study aimed to assess the germination, emergence, physiology and growth of passion fruit seedlings of two varieties under salt water irrigation. The study was conducted in two stages: the first carried out in a laboratory and the second in a greenhouse, using a randomized block design, in a 2 x 4 factorial scheme, corresponding to two passion fruit varieties (BRS RC and BRS GA1) and four levels of irrigation water electrical conductivity (0.2 dS m-1, 2.2 dS m-1, 4.2 dS m-1 and 6.2 dS m-1), with four replications. The BRS GA1 variety exhibited the highest germination index and rate, in the germination stage, despite being more sensitive to salinity than the BRS RC. There was no damage to the photosynthetic apparatus in the BRS GA1 seedlings during growth, as demonstrated by the higher leaf biomass, when compared to the BRS RC variety.

Biofertigation of Forage With Effluents From a Cattle Slaughterhouse Green Line: Impacts on Physical-Chemical Indicators of Soil Quality and on Production Biomass

Cattle slaughterhouses are potential causes the environmental impacts, as it require a large volume of water in meat processing, generate large effluents amount, and promote the Cerrado deforestation for animal husbandry. Therefore, we aim was carried out to assess the effects of the soil application of a green line wastewater from a cattle slaughterhouse in the Brachiaria brizantha growth. The M1 and M2 managements did not contain wastewater of slaughterhouse. The wastewater from the 3rd stabilization pond (M3 to M5), from reception box (M6 to M8), and manure (M9 and M10) were used in the biofertigation managements. The physical-chemical indicators levels did not show significant differences (p &lt; 0.05) before soil preparation and after managements. However, biofertigation in the Cerrado soil can provide a mitigation of the leaching of fine soil particles and cations. In addition, maximum nitrogen dose of wastewater provided a higher leaf biomass productivity than commercial nitrogen. Thus, the fertigation with wastewater can reduce the use of water bodies to crops irrigation and the incorporation of new areas with native vegetation to the agricultural production systems.

Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus

Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearson's correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials.

Seasonal and canopy height variation in n-alkanes and their carbon isotopes in a temperate forest

The stable carbon isotopic composition (δ13C) of terrestrial leaf wax components, such as n-alkanes (δ13Calk), is used extensively to address questions about past changes in vegetation, climate and the carbon cycle. To interpret sedimentary δ13Calk values, characterization of the environmental and biological controls on carbon isotopic fractionation during plant metabolism is required, especially for fractionation that occurs during photosynthesis (ɛleaf-CO2 or Δleaf) and n-alkane biosynthesis (εalk-leaf). Although much is understood about controls on ɛleaf-CO2, little is known about seasonal or within canopy variation in n-alkane composition and εalk-leaf. To address the gap, we sampled 5 common tree species (Acer rubrum, Acer saccharum, Juniperus virginiana, Sassafras albidum and Ulmus americana) from buds to senescing leaves from within a single temperate forest in southwestern Ohio, USA. We measured n-alkane concentration, δ13Calk, leaf biomass δ13C (δ13Cleaf), δ13C of atmospheric CO2 within the canopy, luminous flux and specific leaf area (SLA). In angiosperms, δ13Calk values were low in the buds, increased substantially (4–6‰) to the highest values in young leaves and then decreased (1–3‰) in mature leaves. Seasonal variation in δ13Calk values generally tracked changes in δ13Cleaf, but the fractionation between leaf and n-alkanes (εalk-leaf) was variable, with lower values in buds (−6.7 ± 1.1‰) than in young leaves (−4.9 ± 2.3‰). Later in the growing season, εalk-leaf values stabilized and ranged between −2.5 and −6.5‰, with a mean of −4.3 ± 1.4‰ in angiosperms. Stabilization of δ13Calk values coincided with settling of SLA and increase in average chain length (ACL). For the conifer, temporal variation in δ13Calk values was smaller (ca. 2‰) compared with the angiosperms, and εalk-leaf values slightly increased when n-alkane production increased. Average εalk-leaf value in the conifer at the end of the growing season was −5.0 ± 0.7‰. We speculate that εalk-leaf variation in both angiosperms and the conifer reflects changes in the source of carbon for plant metabolism, as well as the timing of wax synthesis. We also tested canopy effects on n-alkane concentration and carbon isotopic fractionation at different heights and extent of canopy closure. n-Alkane concentrations were higher at the top of the canopy by 2–8 times than in the lower canopy. The εleaf-CO2 values were more negative at the lower two thirds of the canopy than the upper one third of the canopy by 2–4‰ in two species with closed canopies. The εalk-leaf values did not vary with height and extent of canopy closure. To further explore the link between canopy leaves and leaf litter, we compared δ13Calk values of mature canopy leaves with those in leaf litter collected during senescence, and the offsets were within ca. 1‰. The results confirm indications that leaf litter δ13Calk values reflect those of the upper canopy leaves due to not only high leaf biomass in the upper canopy but also to high n-alkane production.

Tolerance and bioaccumulation of Cd and Cu in Sesuvium portulacastrum

In order to investigate the tolerance and bioaccumulation of Cd and Cu in the halophyte Sesuvium portulacastrum, seedlings were hydroponically cultured for 30 days using the modified 1/2 Hoagland nutrient solution with different concentrations of Cd (0, 5, 10, 15, and 20mgL−1) and Cu (0, 2.5, 5, 7.5, and 10mgL−1). Afterwards, the seedling height, leaf area, biomass, and mineral element contents (Fe, Mg, Cu, and Zn) in the roots, stems and leaves were measured, and the tolerance index, bioconcentration factor (BCF), transportation index, and removal rate were calculated. The effects of salinity (0‰–30‰) on the growth and bioaccumulation ability of S. portulacastrum under combined Cu/Cd (5mgL−1) exposure were also determined. The results showed that, with an increasing Cd concentration, the biomass and seedling height of S. portulacastrum initially increased and then decreased. The highest leaf biomass and seedlings height was observed in the 10mgL−1 and 5mgL−1 Cd treatment group, respectively. Salinity did not affect the biomass of S. portulacastrum but decreased Cd concentration in roots and aboveground tissues and Cu concentration in roots of S. portulacastrum. Cu treatment significantly facilitated the absorption of Mg, Cu, and Zn in roots. With an increasing Cu concentration, the Mg and Fe contents increased in the leaves of S. portulacastrum. In comparison to the above-ground portions, the root showed a higher bioaccumulation ability of Cd and Cu, with the BCF of 341.5 and 211.9, respectively. The BCF and translocation factor (TF) values indicated that S. portulacastrum was not a hyperaccumulator for Cd and Cu, but could be used as a phytostablization plant in heavy metal contaminated coastal environments.

Maize Grain Yield and Kernel Component Relationships to Morphophysiological Traits in Commercial Hybrids Separated by Four Decades

Hybrid era and management practices like nitrogen (N) rate and plant density influence canopy traits and their correlations with grain yield, kernel number, and kernel weight in maize (Zea mays L.). A four site‐year study was conducted employing two N rates (55 and 220 kg N ha−1) with three plant densities between 54,000 and 104,000 plants ha−1 for two newer hybrids (2005) and two older hybrids (1967 and 1975). Hybrids varied in anthesis–silking interval, specific leaf nitrogen (SLN), specific leaf area, and leaf greenness (soil plant analysis development [SPAD] readings), but not in leaf area index (LAI) at silking. Consistently higher kernel weight in newer hybrids (15% in 2012, 23% in 2013) across management treatments was related to their higher SLN at silking and green leaf number retention during grain filling. The threshold LAI at silking for maximum kernel number for 2005 hybrids (averaging 3917 kernels m−2) occurred at 4.0 m2 m−2, compared with 3.28 m2 m−2 for the 1975 hybrid (3893 kernels m−2), and kernel number declined when LAI exceeded 3.43 m2 m−2 for the 1967 hybrid. Higher leaf biomass, leaf N content, and therefore higher SLN at silking in newer hybrids contributed to greater green leaf retention during grain filling. Applying more N weakened correlations between grain yield and canopy attributes, including leaf retention in both years and yield correlations with leaf biomass, leaf N content, LAI, and SLN in 2013 (more favorable weather). Grain yields for all hybrids in 2013 had higher correlations with LAI at silking and during grain fill when grown at higher densities.

Stemflow of a xerophytic shrub (Salix psammophila) in northern China: Implication for beneficial branch architecture to produce stemflow

Summary Stemflow is an important mechanism to replenish soil water for xerophytic shrubs in water-stressed ecosystems, whereas the biotic influences of leaf and branch on shrub stemflow were not completely investigated. In this study, the stemflow of 98 branches with various basal diameter under 42 rainfall events was measured for Salix psammophila in northern China during the rainy seasons of 2014 and 2015. The effects of rainfall characteristics, and plant traits of leaf and branch on stemflow were detected. Stemflow productivity (branch stemflow production of unit biomass) was proposed to determine the beneficial branch architecture for efficient stemflow production. The developed allometric equations by expressing the plant traits as a power function of branch basal diameter could satisfactorily estimate the leaf traits and biomass. There were significant differences of branch stemflow between different basal diameter and precipitation classes. The average shrub stemflow depth and percentage was 0.77 mm (0.004–3.32 mm) and 5.54% (0.70–7.92%), respectively. The precipitation amount and leaf fresh biomass were identified as the most influential rainfall characteristic and plant trait of stemflow, respectively. The stemflow production increased linearly with precipitation amount, and stemflow percentage increased with precipitation amount to approach the asymptotic value of 7.61%. The threshold precipitation amount of 2.1 mm was required to initiate shrub stemflow. The stemflow productivity decreased with basal diameter of branches and increased with precipitation amount. Allocating aboveground biomass to grow new branches and develop small ones was an energy-conserving strategy to ensure stemflow production. The branch architecture with more small branches, higher leaf biomass, and larger branch angle was more efficient for stemflow production.