Sweet potato (Ipomoea batatas) is one of the most important food crops worldwide and its leaves provide a dietary source of nutrients and various bioactive compounds. These constituents of sweet potato leaves (SPL) vary among varieties and play important roles in treating and preventing various diseases. Recently, more attentions in health-promoting benefits have led to several in vitro and in vivo investigations, as well as the identification and quantification of bioactive compounds in SPL. Among them, many new compounds have been reported as the first identified compounds from SPL with their dominant bioactivities. This review summarizes the current knowledge of the bioactive compositions of SPL and their health benefits. Since SPL serve as a potential source of micronutrients and functional compounds, they can be further developed as a sustainable crop for food and medicinal industries.

Bee pollen is a nutrient-rich food that meets the nutritional requirements of honey bees and supports human health. This study aimed to provide nutritive composition data for 11 popular bee pollen samples (Brassica napus (Bn), Bidens pilosa var. radiata (Bp), Camellia sinensis (Cs), Fraxinus griffithii (Fg), Prunus mume (Pm), Rhus chinensis var. roxburghii (Rc), Bombax ceiba (Bc), Hylocereus costaricensis (Hc), Liquidambar formosana (Lf), Nelumbo nucifera (Nn), and Zea mays (Zm)) in Taiwan for the global bee pollen database. Macronutrients, such as carbohydrates, proteins, and lipids, were analyzed, which revealed that Bp had the highest carbohydrate content of 78.8 g/100 g dry mass, Bc had the highest protein content of 32.2 g/100 g dry mass, and Hc had the highest lipid content of 8.8 g/100 g dry mass. Only the bee pollen Hc completely met the minimum requirements of essential amino acids for bees and humans, and the other bee pollen samples contained at least 1–3 different limiting essential amino acids, i.e., methionine, tryptophan, histidine, valine, and isoleucine. Regarding the fatty acid profile of bee pollen samples, palmitic acid (C_16:0), stearic acid (C_18:0), oleic acid (C_18:1), linoleic acid (C_18:2), and linolenic acid (C_18:3) were predominant fatty acids that accounted for 66.0–97.4% of total fatty acids. These data serve as an indicator of the nutritional quality and value of the 11 bee pollen samples.

The rapid light response of electron transport rate (ETR_R), obtained from chlorophyll fluorescence parameters by short illumination periods (10–30 s) at each light level, can provide a rapid and easy measurement of photosynthetic light response in plants. However, the relationship between ETR_R and the steady-state light response of CO₂ exchange rate (A_S) of terrestrial plants has not been studied in detail. In this study, we compared the ETR_R and A_S for five woody and four fern species with different light and/or water adaptations. Under well-watered conditions, a constant temperature (25 °C) and with stomatal conductance (g_s) not being a main limiting factor for photosynthesis, ETR_R and A_S were closely related, even when merging data for regression analysis for a species grown under different light conditions and measured under different light intensity and air humidity. However, when Alnus formosana was treated with low soil water and air humidity, because of the decrease in A_S mainly due to stomatal closure, the ETR_R–A_S relation was not so close. In addition, at both 100 and 2000 μmol m⁻² s⁻¹ photosynthetic photon flux density (PPFD), ETR_R and A_S were significantly correlated within a plant group (i.e., woody plants and ferns) regardless of the broad difference in A_S due to different species or environmental factors. The results indicate that the relationship between the ETR_R and A_S is varied by species. We concluded that 1) ETR_R could reflect the variation in A_S at each irradiance level within a species under well-watered conditions and 2) ETR_R at 100 μmol m⁻² s⁻¹ PPFD (as the efficiency of light capture) or 2000 μmol m⁻² s⁻¹ PPFD (as a maximum photosynthetic parameter) could be used to compare the photosynthetic capacity within a plant group, such as woody plants and ferns.

Sod culture (SC) and no tillage (NT) are modern orchard management systems, and are two different bases for the sustainable development and production of citrus orchards in Taiwan. However, there is no information about the efficiency of either NT or SC on the photosynthetic physiology of farmed citrus under different seasons and varying light intensities. The objective of this study was to clarify the impacts of SC and NT under eco-friendly farming management on the photosynthetic apparatus of an important plantation citrus species in response to varying light intensities over the seasons. The results showed that Rd (dark respiration rate of CO₂), Qy (light quantum yield of CO₂), LCP (light compensation point), Amax (maximum net assimilation of CO₂), and Fv/Fm values of citrus plants under SC were somewhat higher under NT in the same season, particularly in the fall and in winter. As light intensity increased from 200 to 2000 μmol photon m⁻² s⁻¹ PPFD, higher Pn (net photosynthesis rate), Gs (stomatal conductance), ETR (electron transport rate), NPQ (non-photochemical quenching), and Fv/Fm (potential quantum efficiency of PSII) values were observed in spring and summer compared to the fall and winter, and increasing NPQ and decreasing Fv/Fm values were observed in all seasons. Positive and significant correlations were shown between the Pn and Gs under NT and SC in all seasons with all light illuminations, whereas significant and negative relationships were observed between the ETR and NPQ under NT in fall and winter at 1200~2000 PPFD. In short, ETR was useful for non-destructive estimations of Pn and NPQ since these indices were significantly and positively correlated with ETR in citrus leaves exposed to 0~1200 PPFD in all seasons and 1200~2000 PPFD in spring, the fall, and winter, providing a quick means to identify the physiological condition of plants under various seasons and tillages. The precise management of photosynthetic parameters such as ETR in response to light irradiances under varied seasons also provides implications for sustainable citrus production for tillage cropping systems in future higher CO₂ and potentially wetter or drier environments. The tillages may hold promise for maximizing the economic efficiency of the growth and development of citrus plants grown in the field.

Mangrove ecosystems are vulnerable to rising sea levels as the plants are exposed to high salinity and tidal submergence. The ways in which these plants respond to varying salinities, immersion depths, and levels of light irradiation are poorly studied. To understand photosynthesis in response to salinity and submergence in mangroves acclimated to different tidal elevations, two-year-old seedlings of two native mangrove species, Kandelia obovata and Rhizophora stylosa, were treated at different salinity concentrations (0, 10, and 30 part per thousand, ppt) with and without immersion conditions under fifteen photosynthetic photon flux densities (PPFD μmol photon·m⁻²·s⁻¹). The photosynthetic capacity and the chlorophyll fluorescence (ChlF) parameters of both species were measured. We found that under different PPFDs, electron transport rate (ETR) induction was much faster than photosynthetic rate (Pn) induction, and Pn was restricted by stomatal conductance (Gs). The Pn of the immersed K. obovata plants increased, indicating that this species is immersed-tolerant, whereas the Pn level of the R. stylosa plants is salt-tolerant with no immersion. All of the plants treated with 30 ppt salinity exhibited lower Pn but higher non-photochemical quenching (NPQ) and heat quenching (D) values, followed by increases in the excess energy and photoprotective effects. Since NPQ or D can be easily measured in the field, these values provide a useful ecological monitoring index that may provide a reference for mangrove restoration, habitat creation, and ecological monitoring.

Limited information is available regarding the physiology of squash plants grown under waterlogging stress. The objectives of this study were to investigate the growth and physiological performances of three cucurbit species, Cucurbita maxima cultivar (cv.) OK-101 (OK) and Cucurbita moschata cv. Early Price (EP) and Strong Man (SM), in response to waterlogging conditions, and to develop a precise, integrated, and quantitative non-destructive measurement of squash genotypes under stress. All tested plants were grown in a growth chamber under optimal irrigation and growth conditions for a month, and the pot plants were then subjected to non-waterlogging (control) and waterlogging treatments for periods of 1, 3, 7, and 13 days (d), followed by a 3-d post-waterlogging recovery period after water drainage. Plants with phenotypes, such as fresh weight (FW), dry weight (DW), and dry matter (DM) of shoots and roots, and various physiological systems, including relative water content (RWC), soil and plant analysis development (SPAD) chlorophyll meter, ratio of variable/maximal fluorescence (Fv/Fm), quantum photosynthetic yield (YII), normalized difference vegetation index (NDVI), and photochemical reflectance index (PRI) values, responded differently to waterlogging stress in accordance with the duration of the stress period and subsequent recovery period. When plants were treated with stress for 13 d, all plants exhibited harmful effects to their leaves compared with the control, but EP squash grew better than SM and OK squashes and exhibited stronger tolerance to waterlogging and showed less injury. Changes in the fresh weight, dry weight, and dry matter of shoots and roots indicated that OK plants suffered more severely than EP plants at the 3-d drainage period. The values of RWC, SPAD, Fv/Fm, YII, NDVI, and PRI in both SM and OK plants remarkably decreased at waterlogging at the 13-d time point compared with controls under identical time periods. However, the increased levels of SPAD, Fv/Fm, YII, NDVI, and PRI observed on 7 d or 13 d of waterlogging afforded the EP plant leaf with improved waterlogged tolerance. Significant and positive correlations were observed among NDVI and PRI with SPAD, Fv/Fm, and YII, indicating that these photosynthetic indices can be useful for developing non-destructive estimations of chlorophyll content in squashes when screening for waterlogging-tolerant plants, for establishing development practices for their cultivation in fields, and for enhanced cultivation during waterlogging in frequently flooded areas.