Almost all of a plant’s life activities involve electrochemical reactions. Plant electrical parameters respond quickly to environmental changes and are closely related to physiological activities. In this study, the theoretical intrinsic relationships between clamping force and leaf impedance (Z) or capacitive reactance (Xc) and capacitance (C) were revealed as 3-parameter exponential decay and linear models based on bioenergetics, respectively, for the first time. Leaf electrical characteristics including intrinsic impedance (IZ), capacitive reactance (IXc), capacitance (IC) and specific effective thickness (d) were successfully detected using the above-mentioned relationships and were used to manifest plant metabolic activity. The intracellular water-holding capacity (IWHC), water-use efficiency (IWUE), water-holding time (IWHT) and water transfer rate (WTR) of plant leaves were defined on the basis of IZ, IXc, IC and d, and applied to reflect the intracellular water metabolism. The results demonstrated that the leaves of Broussonetia papyrifera plants grown in agricultural soil had higher IC, d, IWHC, WTR, water content values and lower IZ, IXc values than those grown in moderately rocky desertified soil. The leaf IC, d, IWHC, WTR and water content values of herbaceous plants were higher than those of woody plants. Solanum tuberosum L. had higher leaf IC, d, IWHC and WTR values, but exhibited lower IZ, IXc, IWUE and IWHT values than Capsicum annuum L. This study highlighted that a plant’s electrical parameters based on bioenergetics clearly indicate its physiological process—e.g., the intracellular water metabolism.

P deficiency in karst areas significantly influenced leaf photosynthesis and carbon metabolisms in plants which were bad for plant growth. Meanwhile, fertilizer application would cause lots of environmental problems. Therefore planning and developing P deficiency-resistant plants in karst areas are important to prevent shortage of P resources and reduce the environmental impacts of P supplementation. This study examined the photosynthetic response of three climber plant species, namely, Pharbitis nil (Linn.) Choisy, Lonicera pampaninii Levl, and Parthenocissus tricuspidata (Sieb.et Zucc.) Planch to phosphorus (P) deficiency stress. The plants were exposed to P deficiency stress at three treatments of 0.125 mM, 0.031 mM, and 0 mM for 30 d; 0.250 mM P was used as the control. Photosynthetic responses were determined by measurement of leaf photosynthesis, chlorophyll fluorescence, carbonic anhydrase activity, and stable carbon isotope ratios. Pharbitis nil showed high CA activity, more negative δ13C values and could maintain long-term stable photosynthetic capacity. Lonicera pampaninii also showed high CA activity but positive δ13C values compared to Pharbitis nil, and its photosynthetic capacity decreased as P deficiency stress increased. Parthenocissus tricuspidata had a low photosynthesis and positive δ13C values compared to Pharbitis nil, it could grow normally even under 0 mM P. Pharbitis nil was tolerant to long-term, severe P deficiency stress, a finding that is attributed to its stable PSII and regulation of carbonic anhydrase. Lonicera pampaninii showed a poor adaptability to short-term P deficiency, but exhibited long-term tolerance under 0.125 mM P concentration. Parthenocissus tricuspidata was tolerant to long-term P deficiency stress, may exhibit a stomatal limitation. Besides, P deficiency stress had little effect on the way of inorganic carbon utilization of the three climber plants. Different adaptation mechanisms to P deficiency stress should be considered for the selection of species when developing P deficiency-resistant plants.

The nutrient metabolism, growth and development of plants are strongly affected by its nutrient plunder, and plants have different adaptive mechanisms to low-nutrient environments. The electrophysiological activities involve almost all life processes of plants. In this study, the active transport flow of nutrient (NAF) and nutrient plunder capacity (NPC) of plants were defined based on leaf intrinsic impedance (IZ), capacitive reactance (IXc), inductive reactance (IXL) and capacitance (IC) to evaluate the nutrient plunder capacity of plants for the first time. The results indicate that Orychophragmus violaceus had higher (p < 0.01) NPC and IC and lower (p < 0.01) IR, IXc, IXL and IZ as compared to Brassica napus L., which supports a superior ion affinity and that it could be better adapted to low-nutrient environments. UAF and NPC of plants exhibited good correlations with crude protein, crude ash and water content, and precisely revealed the plunder capacity and adaptive strategies of plants to nutrients. The present work highlights that O. violaceus had superior NPC and ion affinity compared with B. napus, and provided a novel, rapid, reliable method based on the plant’s electrophysiological information for real-time determination of the nutrient plunder capacity of plants.

Except for transpired water, the intracellular water stored in leaves accounts for only 1–3% of the water absorbed by roots. Understanding water transport and use, as well as the related photosynthetic response, helps with determining plant water status and improving the revegetation efficiency in fragile karst habitats. In this study, we conducted experiments on 8 year old naturally growing plants of Coriaria nepalensis Wall., Broussonetia papyrifera (L.) Vent., and Elaeocarpus decipiens Hemsl. in karst areas. We determined the diurnal variations in leaf electrophysiology, water potential, gas exchange, and chlorophyll fluorescence parameters. The results indicated that C. nepalensis plants maintained a high photosynthetic rate, with a high root water uptake ability and leaf intracellular water-holding capacity (LIWHC). The stomata quickly closed to conserve water within cells and protect the photosynthetic structure. B. papyrifera maintained stable intracellular water transport rate (LIWTR), and the photosynthetic efficiency was increased with increasing intracellular water-use efficiency (LIWUE). B. papyrifera also maintained its photosynthesis by efficiently using the transpired water when the LIWHC was increased. The inter- and intracellular water in the leaves of E. decipiens remained stable, which could be attributed to the leathery leaves and its high water-holding capacity. The photosynthesis of E. decipiens was low and stable. Compared with the high photosynthesis, high transpiration, and low instantaneous water-use efficiency (WUE_i) pattern in C. nepalensis plants, E. decipiens plants exhibited low photosynthesis, low transpiration, and low WUE_i, whereas B. papyrifera plants presented high photosynthesis, low transpiration, and high WUE_i. Plants in karst regions change their transport and use of intracellular leaf water to regulate the photosynthetic performance, which differs among different plant species.

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (E_m), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L⁻¹, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L⁻¹. The 0.125 mmol·L⁻¹ P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L⁻¹ was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant’s adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils.

Lǎo huǒ liàng tāng (Cantonese slow-cooked soup, CSCS) is popular in Guangdong, China, and is consumed by Cantonese people worldwide as a delicious appetizer. Because CSCS serves as an important part of family healthcare, medicinal plants and plant-derived products are major components of CSCS. However, a collated record of the diverse plant species and an ethnobotanical investigation of CSCS is lacking. Because of globalization along with a renewed interest in botanical and food therapy, CSCS has attracted a growing attention in soup by industries, scientists, and consumers. This study represents the first attempt to document the plant species used for CSCS in Guangdong, China, and the associated ethnomedical function of plants, including their local names, part(s) used, flavors, nature, preparation before cooking, habitats, and conservation status. In 2014–2017, participatory approaches, open-ended conversations, and semi-structured interviews were conducted with 63 local people and 48 soup restaurant owners (111 interviews) to better understand the biocultural context of CSCS, emphasizing ethnobotanical uses of plants in Guangdong Province, China. Product samples and voucher specimens were collected for taxonomic identification. Mention Index (QI), frequency of use index (FUI), and economic index (EI) were adopted to evaluate the significance of each plant in the food supply. A total of 97 plant species belonging to 46 families and 90 genera were recorded as having been used in CSCS in the study area. Recorded menus consisted of one or several plant species, with each one used for different purposes. They were classified into 11 functions, with clearing heat being the most common medicinal function. Of the 97 species, 19 grew only in the wild, 8 species were both wild and cultivated, and 70 species were cultivated. Roots and fruits were the most commonly used plant parts in the preparation of CSCS. According to the national evaluation criteria, six of these species are listed on “China’s red list” including two endangered, two critically endangered, one near-threatened, and one vulnerable species. The QI, FUI, and EI of the 97 species in the study varied between 0.09 and 1, 0.23 and 9.95, and 0.45 and 6.58, respectively. As an important part of Cantonese culture, CSCS has been popularized as a local cuisine with a healthcare function. CSCS also reflects the plant species richness and cultural diversity of Guangdong Province. Future research on the safety and efficacy of CSCS as well as on ecological and cultural conservation efforts is needed for the sustainable growth of China’s botanical and medicinal plant industry.