Hyperspectral remote sensing, visible light remote sensing and canopy color analysis have been widely concerned for rapid diagnosis of crop growth and nutrition. They are expected to develop into ...potential nondestructive diagnostic techniques for crop nitrogen nutrition in the new era on account of the advantages of stable, rapid, convenient and nondestructive results, together with the good correlation between canopy color parameter NRI and plant nitrogen nutrition index and yield satisfying the demand for nondestructive diagnosis of nitrogen nutrition, and their feasibility to monitor plant growth status and nitrogen nutrition level in real time and quickly. At present, with the rapid development of remote sensing satellite, unmanned aerial vehicles remote sensing and Internet of things, remote sensing will be more and more widely used in plant nutrition diagnosis.
This paper studies the concentration of Pb, Cd, Hg and As in vegetable and soil of 13 main vegetable base, Chongqing, China, as well as the correlation between them. Results show that the ...concentrations of heavy metals in different vegetables from 13 main vegetable bases of Chongqing are also significantly different. The order of Pb concentration is root vegetable (the average value is 0.203 mg/kg) > leaf vegetable (the average value is 0.065 mg/kg) > solanaceous vegetable (the average value is 0.004 mg/kg); the order of Cd concentration is leaf vegetable (the average value is 0.090 mg/kg) > solanaceous vegetable (the average value is 0.061 mg/kg) > root vegetable (the average value is 0.049 mg/kg); the order of Hg concentration is leaf vegetable (the average value is 0.004 mg/kg) > root vegetable (the average value is 0.003 mg/kg) > solanaceous vegetable (the average value is 0.001 mg/kg); the order of As concentration is root vegetable (the average value is 0.116 mg/kg) > solanaceous vegetable (the average value is 0.057 mg/kg) > leaf vegetable (the average value is 0.026 mg/kg). Significant positive correlation was found between the Cd concentration in vegetables and the Cd concentration in soil, and the linear equation was
y
= 0.065 + 0.012
x
. There was no significant correlation between the concentrations of Pb, Hg and As in vegetables and Pb, Hg and As in soil.
Phytoremediation of heavy metal-contaminated soil is considered to be one ecological environmental protection way that is effective and economical. The selection of suitable hyperaccumulators is a ...key issue for phytoremediation of heavy metal-contaminated soil. Pot experiments were conducted to study the effects of different Cd levels (0, 75, 150, 300, and 600 mg kg
−1
Cd) on the dry weight, antioxidant enzyme activities, malondialdehyde (MDA) contents, Cd concentration, Cd accumulation, and soil Cd form distribution ratio (FDC) of alfalfa (
Medicago sativa
L.) and Indian mustard (
Brassica juncea
L.). The correlations between Cd concentration in shoots and roots of alfalfa and Indian mustard and soil Cd form were also investigated. The results showed that with the increase of soil Cd levels, dry weight of shoot and root of alfalfa and Indian mustard significantly decreased, which decreased by 50.0–71.8% and 29.6–59.3% (alfalfa), 59.6–89.0% and 64.3–74.8% (India mustard), respectively, compared with the control. With the increase of soil Cd level, superoxide dismutase (SOD) activity in shoot of alfalfa significantly increased. Catalase (CAT) activity and malondialdehyde contents in shoots and roots of alfalfa and Indian mustard, as well as superoxide dismutase activity in the roots of alfalfa and Indian mustard increased first and then decreased with the increase of soil Cd level. With increasing Cd stress, Cd concentration in shoots and roots of alfalfa and Indian mustard significantly increased. At soil Cd level of 75 mg kg
−1
, Cd concentrations in shoots of alfalfa and Indian mustard exceeded the critical value of Cd-hyperaccumulator (100 mg kg
−1
), which was 356.46 mg kg
−1
and 308.74 mg kg
−1
, respectively. Cadmium concentrations in shoots and roots of plants were in the order of that of alfalfa > Indian mustard; total Cd accumulation in the aboveground tissues and roots of the plants was in the order of that of Indian mustard > alfalfa at the same Cd level. With increasing soil Cd level, Cd concentrations of exchangeable form (EXC-Cd), carbonate-bound form (CAB-Cd), iron-manganese oxide-bound form (FeMn-Cd), organic-bound form (OM-Cd), and residual form (RES-Cd) showed an increasing trend. The form distribution ratio of soil Cd forms in alfalfa’s rhizosphere was in the order of that of exchangeable form Cd > carbonate-bound form Cd > iron-manganese oxide-bound form Cd > residual form Cd > organic-bound form Cd. Except for organic-bound form Cd, soil Cd forms were significantly positively correlated with Cd concentration in shoot and root (
P
< 0.01). Comprehensively considering the biomass and Cd accumulation, Indian mustard is more suitable as remediation material for soil Cd pollution.
In order to understand the mechanism of the difference of Cd absorption and Cd enrichment in different ryegrass varieties, pot experiment was conducted to study on the response of two varieties of ...ryegrass (Bond and Abbott) to Cd stress as well as the differences of Cd uptake and expression of
MT
family genes and
NRAMP2
. Results showed that root dry weights of two varieties and shoot dry weights of Abbott increased first and then decreased with the increase of Cd level in soil. When exposed to 75 mg kg
−1
Cd, shoot dry weight and plant dry weight of Abbott both reached maximum values (10.92 and 12.03 g pot
−1
), which increased by 11.09 and 10.67% compared with the control, respectively. Shoot dry weight and plant dry weight of Bond decreased with the increase of Cd level in soil. When the Cd level in soil was 75 mg kg
−1
, shoot Cd concentrations of the two varieties were 111.19 mg kg
−1
(Bond) and 133.69 mg kg
−1
(Abbott), respectively, both of which exceeded the critical value of Cd hyperaccumulator (100 mg kg
−1
). The expression of
MT
gene family and
NRAMP2
in the leaf of Bond variety significantly increased at the Cd level of 75 mg kg
−1
and reached maximum value (except
MT2C
) at Cd level of 150 mg kg
−1
. The expression of
MT
gene family in the stem of Bond variety showed a double-peak pattern, while the expression of
NRAMP2
was a single-peak pattern. The expression of
MT
gene family and
NRAMP2
in Abbott variety was consistent with single-peak pattern. The expression of
MT
gene family and
NRAMP2
in leaf both significantly increased at Cd level of 150 mg kg
−1
, while that in stem and root significantly increased at Cd level of 75 mg kg
−1
. For both varieties of ryegrass, the expression amount of
MT
family genes and
Nramp2
in leaf was higher than that in root and stem, indicating the Cd tolerance of ryegrass can be improved by increasing the expression levels of
MT
family genes and
Nramp2
in stem and root. There was significant genotypic difference in the expression of
MT
gene family and
NRAMP2
between the two varieties of ryegrass, and the expression of
MT
gene family and
NRAMP2
in leaves and stems of Bond variety was higher than that in Abbott variety, while the expression of
MT
gene family and
NRAMP2
in roots of Abbott variety was higher than that in Bond variety. The two gene families investigated in this study may be closely related to Cd uptake, but not related to Cd transport from root to leaf and Cd enrichment in shoot.
Pot experiments were conducted to study the effects of different cadmium (Cd) levels (0, 75, 150, 300 and 600 mg kg
−1
) on the growth, cadmium concentration and cadmium accumulation of two varieties ...of ryegrass, and the correlation between plant cadmium concentration and soil cadmium chemical forms. The results showed that root dry weight of the two varieties of ryegrass, dry weight of shoot and plant in Aubade increased first and then decreased with the increase of soil cadmium. When the soil cadmium level was 75 mg kg
−1
, shoot dry weight and plant dry weight in Aubade reached the maximum (10.92 g pot
−1
and 12.03 g pot
−1
), which was 11.13% and 10.67% higher than that of the control respectively. The cadmium form in shoot of the two ryegrass varieties was dominated by was sodium chloride extraction (F-NaCl), followed by deionized water extracted (F-W) and acetic acid extracted (F-HAC). The cadmium forms in soils were mainly exchangeable (EXC-Cd), and cadmium concentrations of leaf, stem and root were significantly positively correlated with exchangeable cadmium content in the rhizosphere soil (
P
< 0.01). The EXC-Cd content in Abbott soil was higher than that in Bond, which was consistent with Abbott’s Cd absorption above Bond. The cadmium transport factor of the two ryegrass varieties were less than 1, and cadmium bioconcentration factor were all greater than 1. In comparison of the two ryegrass varieties, the dry weight of shoot and plant of Abbott were higher than that of Bond under the stress of 75–600 mg kg
−1
Cd. The cadmium concentration and cadmium accumulation of shoot and root in Abbott were also higher than that of Bond. There was a genotypic difference in ryegrass tolerance to cadmium and cadmium absorption. Abbott was more suitable as a phytoremediation material for soil cadmium pollution.
Pot experiment was conducted to study the difference of cadmium uptake and
OAS
and
IRT
genes’ expression between the two ryegrass varieties under cadmium stress. The results showed that with the ...increase of cadmium levels, the dry weights of roots of the two ryegrass varieties, and the dry weights of shoots and plants of Abbott first increased and then decreased. When exposed to 75 mg kg
−1
Cd, the dry weights of shoot and plant of Abbott reached the maximum, which increased by 11.13 and 10.67% compared with the control. At 75 mg kg
−1
Cd, cadmium concentrations in shoot of the two ryegrass varieties were higher than the critical value of Cd hyperaccumulator (100 mg kg
−1
), 111.19 mg kg
−1
(Bond), and 133.69 mg kg
−1
(Abbott), respectively. The
OAS
gene expression in the leaves of the two ryegrass varieties showed a unimodal curve, which was up to the highest at the cadmium level of 150 mg kg
−1
, but fell back at high cadmium levels of 300 and 600 mg kg
−1
. The
OAS
gene expression in Bond and Abbott roots showed a bimodal curve. The
OAS
gene expression in Bond root and Abbott stem mainly showed a unimodal curve. The expression of
IRT
genes family in the leaves of ryegrass varieties was basically in line with the characteristics of unimodal curve, which was up to the highest at cadmium level of 75 or 150 mg kg
−1
, respectively. The
IRT
expression in the ryegrass stems showed characteristics of bimodal and unimodal curves, while that in the roots was mainly unimodal. The expression of
OAS
and
IRT
genes was higher in Bond than that in Abbott due to genotype difference between the two varieties. The expression of
OAS
and
IRT
was greater in leaves than that in roots and stems. Ryegrass tolerance to cadmium can be increased by increasing the expression of
OAS
and
IRT
genes in roots and stems, and transfer of cadmium from roots and stems to the leaves can be enhanced by increasing expression
OAS
and
IRT
in leaves.
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•BTO NRs with a rectangular-like structure were synthesized by hydrothermal reactions.•BTO NRs exhibited outstanding piezo-catalytic activity for molecular water activation.•Ti4+ is ...the active site for the activation of water molecules and the generation of •OH.•Ti4+ and Ti3+ can be interconverted in the catalytic process by donating and accepting electrons.
Using piezoelectric materials for advanced oxidation is a green and viable means of water purification and environmental restoration. However, unmodified piezoelectric catalysts exhibited unsatisfactory catalytic performance, which had become a bottleneck for the practical application of piezoelectric catalysis. In this work, piezoelectric responsiveness and exposed active crystal surface area were rationally coordinated by synthesizing one-dimensional BaTiO3 nanorods (BTO NRs). Enhanced piezo-responsivity enables faster free charge carriers transfer, while the highly exposed area of the (001) facets provides more active sites for piezo-catalytic reactions. Consequently, BTO NRs degraded RHB (Rhodamine B) and TC (Tetracycline) with first-order rate constants of 0.018 min−1 and 0.012 min−1, respectively, 5 times higher than BaTiO3 nanoparticles. The specific active sites on the (001) crystal plane were further investigated through a combination of DFT calculations, free radical trapping experiments, and XPS analysis. Ti4+ adsorbs and activates water molecules to generate Ti3+ and •OH, in the catalytic reaction. Afterward, Ti3+ is oxidized to Ti4+ by piezo-holes (holes driven by piezoelectric potential), while •OH is desorbed and involved in the degradation of pollutants. This research not only provides an approach to modify piezoelectric catalysts with high catalytic activity but also presents new insights into the mechanism of piezoelectric catalysis from the viewpoint of the atom level.
Facing the challenge of freshwater scarcity, solar evaporation technology with interfacial heating is considered to be a technology that uses solar energy to sustainably obtain fresh water through ...evaporation and condensation processes. However, the construction of a solar-driven evaporation system capable of consistently, efficiently, and steadily producing pure water under sunlight is pivotal yet challenging. In this work, inspired by mushrooms, a magnetic-generated double‑layered solar evaporator is designed for efficient water evaporation. With the thermal management of the aerogel and the vertical arrangement of the water channels, this evaporator overcomes the trade-off between water delivery and heat management that has long plagued traditional evaporators. In addition, the presence of cold evaporation breaks the long-existing photothermal efficiency of traditional solar evaporation cannot exceed the limit of 100 %. With this structure, an evaporation rate of 1.966 kg m−2 h−1 and a solar-to-vapor energy efficiency of 120.6 % are achieved under irradiation of 1 sun. The mung beans are irrigated with pure water obtained by evaporation to germination. The work provides a new direction for manufacturing evaporators and key insights into addressing water scarcity and the use of water.
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•We designed the unique double‑layered solar evaporator inspired by the mushroom.•an evaporation rate of 1.966 kg m−2 h−1 and an efficiency of 120.6 % are achieved.•The CFPC was used to solve the problem of freshwater shortage and pollution.•The collected water showed excellent biocompatibility.
