Acta Physiologiae Plantarum

Ben Hamed, Samouna; Lefi, Elkadri; Chaieb, Mohamed

doi: 10.1007/s11738-021-03297-zpmid: N/A

This study tests the diurnal variations of water status, leaf gas exchanges and chlorophyll fluorescence in Pistacia vera L. (P. vera L.) and Pistacia atlantica Desf. (P. atlantica Desf.) seedlings. At 40% of field capacity, diurnal variations in water uptake, relative water content (RWC) were estimated every hour between 5:00 am and 7:00 pm. The daily course of light, temperature, photosynthesis (A), stomatal conductance (gs), transpiration rate (E), intrinsic water use efficiency (A/gs), mesophyll efficiency (A/Ci), internal CO2 concentration (Ci) and chlorophyll fluorescence were measured every 3 h from 05:30 am to 7:30 pm in irrigated and stressed seedlings of the two studied species. The results showed a significant variation in all surveyed parameters over diurnal cycle. The stressed seedlings of P. atlantica exhibited considerably higher RWC, water uptake, A, gs, E, A/gs and A/Ci over diurnal cycles compared to P. vera stressed seedlings. In contrast, P. vera was more sensitive to water stress and excess light and temperature over the diurnal cycle. The midday stomatal conductance and photosynthesis decrease was more likely the result of low RWC caused by high transpiration rates, stomatal closture and photoinhibition. Photoinhibition is a protective mechanism of PSII, rather than a result of photo-damage of photosynthetic apparatus. P. atlantica revealed an important physiological feature that is maintaining photosynthesis at midday compared to P. vera. This might be due to internal regulation through several mechanisms mainly better osmotic adjustment, photoprotective mechanisms of PSII.

Sulaimankhil, Ziaullah; Sethi, Shruti; Sharma, R. R.; Verma, M. K.; Dahuja, Anil; Bhowmik, Arpan

doi: 10.1007/s11738-021-03301-6pmid: N/A

The objective of the present study was to evaluate the effectiveness of aqueous hexanal in prolonging the storage life of apple cv. ‘Royal Delicious’ while maintaining its quality. The influence of different concentrations of aqueous hexanal (1 mM, 2 mM and 3 mM) as a dip treatment for 2, 3 and 4 min was tested. Fruits given no hexanal treatment were taken as control. The treated and control apple fruits were stored under 1–2 °C and 80–90% RH for a period of 90 days and evaluated for physical and biochemical changes at regular interval of 15 days. The current study demonstrated that exogenous application of 1 mM hexanal applied as dip treatment for 3 min soaking time given to ‘Royal Delicious’ apple fruits retained higher firmness, reduced decay and improved the overall quality of the fruits upto 3-month storage under 1–2 °C. To conclude, postharvest application of aqueous hexanal as dip treatment holds promise in prolonging postharvest storage life and preserving quality of apple cv. ‘Royal Delicious’.

Zhang, Xia; Wang, Zhiwei; Li, Haiyun

doi: 10.1007/s11738-021-03303-4pmid: N/A

Koelreuteria integrifoliola, an important ornamental plant, has interference effect on the turf grass. However, the mechanisms of its allelopathy to plants has not been fully elucidated. Here, the allelopathic effects of leaf aqueous extract of K. integrifoliola on the growth, endogenous hormone contents and ultrastructure of Lolium perenne Lam seedlings were investigated. Leaf aqueous extract of K. integrifoliola at different concentrations (25.00, 50.00 and 100.00 mg mL−1) significantly reduced the growth (in terms of dry weight), chlorophyll b, total chlorophyll and carotenoids contents of L. perenne. The results also showed the decline in indole acetic acid (IAA) and gibberellic acid (GA3) contents, and the increase in abscisic acid (ABA) after extract treatment (50.00 and 100.00 mg mL−1). In addition, the (IAA + GA3)/ABA ratios in root and leaf decreased with the increase of extract concentrations. Upon exposure to extracts (50.00 and 100.00 mg mL−1), L. perenne mesophyll cell showed structural abnormalities, mostly including chloroplast distribution, destruction of chloroplast membrane and thylakoid membrane, increment of plastoglobuli number, dissolution of mitochondrial membrane and disappearance of the internal ridge. Furthermore, the chloroplast number and chloroplast volume in L. perenne mesophyll cell showed a concentration-dependent decline exposed to extracts. Thus, the changes of endogenous hormones contents and their ratios, the ultrastructure changes of mesophyll cells caused by the K. integrifoliola leaf aqueous extracts are partly responsible for allelopathic inhibition of receptor plants.

Zhang, Jinyan; Xie, Shiqing; Yan, Suo; Xu, Wenguo; Chen, Junwen

doi: 10.1007/s11738-021-03298-ypmid: N/A

Light is the most essential environmental factor that plants require for the growth and development. However, light is highly heterogeneous in natural condition, and plants have to evolve a series of strategies to acclimate the dynamic light since it is sessile. The photosynthetic performance and regulatory mechanisms involved in acclimation were elucidated in shade-tolerant plant Amorphophallus xiei under steady state and fluctuating high light. The dissipation and allocation of light energy, photosynthetic capacity, and antioxidant defense were examined in A. xiei cultivated under 4%, 17%, and 100% of full sunlight. High-light-grown plants exhibited reduced photosynthesis and the slowest response to simulated sunflecks than the other two treatments. Maximum and actual efficiency of PSII photochemistry (Fv′/Fm′ and ΦPSII) and electron transport rate (ETR) were lowest, and non-photochemical quenching (NPQ) were highest in high-light-grown plants than in low- and intermediate-light-grown plants subjected to different photon flux densities (PFD) and intercellular CO2 concentrations (Ci). Fv′/Fm′, ΦPSII, ETR and NPQ were lowest in high-light-grown A. xiei than others, when plants were exposed to simulated sunflecks. In fully light-induced leaves, high-light-grown plants showed a maximum value in quantum efficiency of light-dependent thermal dissipation (ΦNPQ), and a minimum value in ΦPSII was recorded. Low-light-grown plants subjected to simulated sunflecks, a maximum value in ΦNPQ and ΦPSII were observed. Mass-based nitrogen content (Narea), specific leaf area (SLA), superoxide dismutase (SOD) and catalase (CAT) activities significantly declined with the increase of growth irradiance. The high-light-grown plants showed higher xanthophyll de-epoxidation and ascorbate–glutathione cycle activity, while low-light-grown plants showed higher neoxanthin and β-carotene contents. In general, high-light-grown A. xiei generally show a depressed photosynthetic capacity, and are efficient in dissipating excess light energy by NPQ under a steady-state light but not under a highly fluctuating light. Low-light-grown plants show a rapid photosynthetic assimilation response to sunflecks and then a rapid activation of the energy-dependent quenching (qE) component of NPQ under the sunflecks. In addition, high-light-grown plants, although using various strategies to reduce light absorption and to scavenge reactive oxygen species, have less efficient protection against photodamage.

Rehman, Rana Naveed Ur; Ali, Sajid; Hasan, Mahmood Ul; Anwar, Raheel; Haider, Muhammad Wasim; Khan, Ahmad Sattar; Malik, Aman Ullah; Pengmin, Li

doi: 10.1007/s11738-021-03302-5pmid: N/A

Effect of low temperature and low oxygen concentration on biochemical attributes, antioxidant enzyme activities, phenolics profile and expression of phenylpropanoid pathway-related genes was investigated in crabapple (Malus profusion) fruit. Crabapple fruit were kept at room temperature (RT, 20 ± 2 °C and 25 ± 2 °C alternatively at 12 h cycle) or low temperature (LT, 10 ± 2 °C and 25 ± 2 °C alternatively at 12 h cycle) and supplemented with either normal oxygen (21%) or low oxygen levels (5%) for 9 days. Results revealed higher concentrations of soluble solids, titratable acids, and ascorbic acid in fruit stored at LT + 5% O2. Likewise, total phenolics, peroxidase activity, and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical scavenging activity were observed to be significantly higher in fruit stored at low temperature (LT + 5% O2 > LT + 21% O2), followed by those stored at room temperature (RT + 5% O2 > RT + 21% O2). In contrast, H2O2 and malondialdehyde contents were significantly enhanced in fruit stored at room temperature (RT + 21% O2 and RT + 5% O2), whereas fruit stored at low temperature showed minimum inhibition in superoxide dismutase, catalase and ascorbate peroxidase activities. In addition, low temperature induced biosynthesis of phenolic acids, whereas no considerable changes were observed in flavanols and dihydrochalcones during storage. Low temperature and oxygen conditions (LT + 5% O2) significantly enhanced the biosynthesis of flavonols (glycosylated quercetin derivatives) and cyanidin 3-galactoside, compared to LT + 21% O2, RT + 5% O2 and RT + 21% O2 conditions. In addition, low temperature also up-regulated the expression of MpFLS and MpUFGT in fruit tissues. Moreover, correlation analysis suggested positive association of antioxidant capacity with the biosynthesis of flavonols and anthocyanins in fruit stored at LT + 5% O2.

Salika, Ramazan; Riffat, John

doi: 10.1007/s11738-021-03296-0pmid: N/A

Maize (Zea mays) is the most widely grown crop throughout the world. Its response against various environmental stress factors is quite complex and dynamic, and can be either elastic (reversible) or plastic (irreversible) in nature. Climatic change on the other hand is expected to increase the intensity and frequency of both abiotic and biotic stress factors. In this context, we review the literature on climate change consortium with abiotic stress highlighting the scenario of this nutritionally valuable crop plant and its elicited responses at morphological, physiological, biochemical and phytochemical levels. Besides, ‘omic’ architecture of the plant toward multiple stress factors is also discussed as a report of its first kind. Despite significant knowledge gaps that still exist, it is evident that climate change is going to influence the abiotic stress tolerance mechanisms in plants in general and maize in particular. While broad generalizations are not yet possible, because the specific plant responses towards one type of stress at one time or multiple stresses differ considerably. However, a better understanding of underlying response mechanisms regulated in the face of climate change-associated abiotic stress is needed to safeguard the optimal resilience and productivity of the maize.

Abo Gamar, Mohammad I.; Dixon, Sage L.; Qaderi, Mirwais M.

doi: 10.1007/s11738-021-03299-xpmid: N/A

Interactive effects of temperature, carbon dioxide (CO2), and watering regime on the reproductive yield of plants have not yet been fully understood. We grew Arabidopsis thaliana (wild-type (WT) and abi1-1, ABA-insensitive mutant) plants under two temperature regimes (22/18 °C and 28/24 °C; 16 h light/8 h dark), two CO2 concentrations (400 and 700 μmol mol–1), and two watering regimes (well-watered and water-stressed) for 34 days, and measured plant growth, reproductive yield and seed free amino acids. Plant growth and yield were decreased by higher temperatures and water stress, but aborted seed number was increased by water stress. Stem height and aborted seed number were decreased, but silique width and mass were increased, by elevated CO2. Stem diameter, and silique width and mass were lowest in the water-stressed abi1-1 plants grown under higher temperatures at elevated CO2. Under higher temperatures, elevated CO2 and water stress, the abi1-1 plants produced seeds with lower amino acids than the WT plants. Most amino acids were increased by higher temperatures and elevated CO2 than by water stress. Elevated CO2 partially mitigated the adverse effects of stresses on some traits in both genotypes, with a larger extent in the WT plants than in the abi1-1 plants, and indirectly indicating the role of endogenous ABA in the process.

Gaion, Lucas A.; Carvalho, Rogério F.

doi: 10.1007/s11738-021-03286-2pmid: N/A

It has been shown that gibberellin (GA) perception is part of root-to-shoot communication in plants during drought. However, it is not clear how GA content interferes with long-distance drought response signaling. Thus, in this study, the tomato (Solanum lycopersicum L.) cultivar Micro-Tom (MT) was treated with 50 mM acid gibberellic, while the control plants were sprayed with water. After treatment, tomato plants were reciprocally grafted (i.e., MT/MT, MT + GA/MT + GA, MT + GA/MT, MT/MT + GA; within each pair, the first indicates the scion, and the second indicates the rootstock). Therefore, to evaluate the role of GA in root-to-shoot communication during drought stress, plants were grown under well-watered or drought conditions. Height, leaf and root area, dry weight, malondialdehyde content, relative water content and stomatal conductance were measured. It was verified that the MT + GA/MT and MT + GA/MT + GA plants were taller than the grafted plants without GA treatment. Furthermore, non-treated plants (MT/MT) exhibited a reduction in root area due to water-deficit. Regarding water relations, under drought, the greatest reduction in stomatal conductance was observed in plants grafted onto rootstocks treated with GA, which favored the maintenance of an increased relative water content. This demonstrates an important role of GA in root-to-shoot communication to induce stomatal closure during water-deficit conditions.

Mohammadi, Samaneh; Azizi, Majid; Vaezi, Jamil; Taghizadeh, Seyedeh Faezeh

doi: 10.1007/s11738-021-03300-7pmid: N/A

Thyme (Thymus spp.) is a valuable genus of Lamiaceae family presents a wide range of functional possibilities in the cosmetic, pharmacy, and food industries. T. daenensis and T. pubescens are thymol and carvacrol rich species growing in Iran. The aim of this study was to compare the macro- and micro-morphological, cytogenetical, and biochemical traits present in hermaphrodites and females of T. daenensis and T. pubescens. The analyses were performed by light microscopy (LM) to be compatible with scanning electron microscope (SEM) and gas chromatograph–mass spectrometry (GC–MS). The principal component analysis (PCA) loading plot was carried out using the original numerical data of quantitative characters (e.g., morphological, functional, and life-history traits). Results of gynodioecy analysis showed that the distribution of females in T. daenensis (58.33%) was significantly more than T. pubescens (9.1%). Peltate and capitate glandular trichomes (PGTs and CGTs, respectively) existed in both hermaphrodites and females of T. daenensis and T. pubescens. The size of PGTs in hermaphrodites was significantly larger than these GTs in females. The highest level of thymol and carvacrol was observed in both sexes of T. daenensis and T. pubescens, respectively. The results of the non-metric multidimensional scaling (NMDS) ordination showed separation of hermaphrodite and female types according to essential oil (EO) components. Based on the flow cytometric analysis, the obtained histograms confirmed that T. pubescens and T. daenensis were diploid and tetraploid, respectively. Variation among species and environmental/geographical factors result is differences in the content of thymol and carvacrol in various Thymus species which should be taken into consideration when applying these plants as therapeutic products.

Qin, Shiyu; Xu, Yafang; Liu, Hongen; Li, Chang; Yang, Yu; Zhao, Peng

doi: 10.1007/s11738-021-03290-6pmid: N/A

The objective of this study was to evaluate the effect of boron (B) fertilizer application on the yield and nutritive element content of wheat grain. A field experiment was conducted using wheat at five B treatments consisting of B0 (no B added), B0.2, B0.4, B0.8 and B1.6 (B added at 0.2, 0.4, 0.8 or 1.6 mg kg−1 B, respectively). Boric acid was added to soil to create five B concentrations. Results showed that the there was no significantly difference on yield and thousand seed weight of wheat among different B application treatments. The wheat plant showed a higher B concentration in the root, leaf and shell but lower B concentration in stem and grain. There was an increasing trend for the B concentrations in root, middle stem, leaf and grain with increasing B levels, especially B concentration in grain at B0.8 treatment. However, the translocation factors (TFs) in grain/shell is low. These results suggested that B is easily absorbed by wheats, but not easily transferred to the grain site. In addition, there was an increased tendency for calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe) and zinc (Zn) concentrations with increased B treatment. Grey correlation model analysis showed that the synthetic characteristics of grain (expressed as grey relation degree) followed the sequence of B1.6 > B0.8 > B0 > B0.4 > B0.2. Our results demonstrate that the integrated grain quality is optimal at 1.6 mg kg−1 B concentration in moderate B level soil.