Volume 34 (2022): Issue 1 (June 2022)

In nature, plants are constantly challenged by an array of drought episodes, which critically affect the distribution of the plants. The drought episodes might occur recurrently, so the plants endure drought by adjusting and shifting their metabolisms. The impacts of subjecting plants to drought stress have been widely investigated, but reports on how reiterated drought stress affects the plants are limited. The present study was designed to investigate the response of lavender, a reputed medicinal and aromatic plant, against single drought, recovery and reiterated drought stress at greenhouse conditions. In this regard, the experimental design was based on three cycles of 11 days of drought by withholding water, followed by subsequent periods of 6 days of recovery, and then double-stressed and single-stressed periods. As expected, the present findings revealed that single stress decreased the fresh and dry weights of the leaf, stem and root. Reiterated drought stress caused critical reductions in the fresh weight of the leaf, stem and root, while the dry weight of stem and root were not significantly affected. Of the estimated traits, only the dry weight of leaf increased with reiterated drought stress. The mineral status of the leaves was adversely affected with single stress, but the effects of recovery and reiterated stress were not in accordance with the improvement in water contents of the leaf and soil. Regarding essential oil compounds, eucalyptol, camphor and endo-borneol were predominant. Single and reiterated drought stress increased camphor percentage, while recovery and full irrigation decreased the percentage. Endo-borneol was decreased under single stress, but reiterated stress increased the percentage of the compound. Considering the phenolic acids, stressed and non-stressed groups were well discriminated and hence, phenolic acids might be useful as good indicators of the stress response in lavender.

A controlled environment and composition of the compost used for the commercial production of Agaricus bisporus can allow fruiting bodies with increased nutritional value to be obtained. The present study aimed first to investigate the content of bioelements in fruiting bodies of A. bisporus harvested from three flushes of cultivation and to estimate which elements are accumulated most effectively by determination of bioconcentration factor (BCF). The second aim of the study is to determine the amount of selected organic compounds in the A. bisporus fruiting bodies harvested from three flushes of cultivation and to evaluate their antioxidant activity. Among the three examined A. bisporus flushes, the first is considered the most valuable, since it was rich in dietary and nutritional substances, and has shown promise of antioxidant and antidepressant activities. The present study is the first to describe a complex evaluation of the content of bioactive substances and antioxidant activity in three different cultivation flushes of A. bisporus fruiting bodies.

Plant biostimulants have been used to reduce the damage caused by different types of biotic and abiotic stresses. Iodine (I) is a non-essential element in plants. Still, it is considered beneficial and a biostimulant, since exogenous application can enhance the redox metabolism, which improves antioxidants, synergies with essential minerals and increases tolerance to adverse factors. However, little is known about the mechanism of action of iodine; so, it is advantageous to undertake research that elucidates the impact of this element on plant physiology, which is expected to encourage the productive agricultural sector to use this element with additional biofortification benefit. The objective of this research was to evaluate the effect of foliar KIO₃ applications every 15 days at 100 μM, on growth, mineral content and antioxidants in tomato plants grown under greenhouse conditions subjected to salinity stress (100 mM NaCl). The results showed that iodine did not mitigate the adverse impact of salinity on fresh or dry biomass but increased fruit production by 23%. A greater amount of N and Fe was also found in the leaves but not in the fruits; the same happened with the iodine concentration, which was high in the leaves of the treated plants but not in tomato fruits. The content of Ca and Mg in fruits was decreased in plants treated with iodine, as well as the activity of the GPX, lycopene and the antioxidant potential. None of the fruit quality variables were affected by salinity with or without application of iodine.

Asparagus cochinchinensis (Lour.) Merr is a medicinal, edible and horticulture plant. Seedling breeding relies on tissue-cultured technology, but the transplant from tissue-cultured seedlings to field cultivation poses a problem in the large-scale production of A. cochinchinensis. Tissue-cultured seedlings of A. cochinchinensis were used as materials, and they were transplanted into the substrates that were mixed with coconut bran, peat, vermiculite, perlite or garden soil. The analysis of the physical and chemical properties of the substrate, combined with the survival rate of seedlings, the aboveground parameters (plant height, stem diameter, fresh weight and dry weight), underground parameters (root fresh weight, root dry weight, root length, root diameter, root surface area and root volume) and physiological indexes (malondialdehyde, soluble protein, soluble sugar, proline, chlorophyll and root vigour), allow us to understand the effects of different combination substrates on the growth and physiology of A. cochinchinensis tissue-cultured seedlings. We concluded that the survival rate of seedlings was negatively correlated with the bulk density and conductivity and was positively correlated with the porosity in the substrate. The membership function was used to comprehensively evaluate the indexes of each combination substrate, and it was concluded that coconut bran:perlite:vermiculite = 33.33%:33.33%:33.33% (bulk density = 0.23 g · cm⁻³, total porosity = 65.07%, pH = 6.30, conductivity = 0.51 mS · cm⁻¹) scored the highest, the survival rate of seedlings reached 87.10%, the aboveground and underground growth were vigorous and the quality was better than other substrates. This research provides technical support for the efficient cultivation of tissue-cultured seedlings of A. cochinchinensis and reduces the cost of raising seedlings.

This article describes the changes taking place in the functions of allotment gardens, their perceived value, reasons for purchasing allotments and subjective (self-reported) assessments of their importance during the pandemic. A questionnaire survey was conducted among 203 owners of allotment gardens located in three highly urbanised cities in the Silesian Voivodeship (Southern Poland). Semi-structured questionnaires and non-standardised questionnaires were used to collect the data. The results demonstrate that the respondents aged above 61 years (38.5%) have observed a generational change in the function of allotments, from cultivating fruits and vegetables to recreational purposes. Regardless of age, the owners of allotment gardens did not notice any technological progress or new crops. The young respondents (21–30 years) treated allotment gardens as an investment (36.7%), while the respondents aged below 20 years and over 61 years declared that the greatest benefits of allotment gardening are improved health and growing one’s own fruits and vegetables. The respondents aged over 41 years (25.9%) also pointed out the importance of growing their own produce. Allotments were especially important during the pandemic as a private space free from COVID-related restrictions. Extended interviews with the respondents revealed that allotment gardening was perceived as a coping strategy for the stress generated during the lockdown. This study showed that allotment gardens are important sites not only for food production but also for maintaining mental health, social capital and environmental engagement.

Anthocyanins play a critical role in flower colour pattern formation, and their biosynthesis is typically regulated by transcription factors (TFs). Curcuma alismatifolia is a well-known ornamental plant with colourful flowers. However, little is known about the genes that regulate anthocyanin accumulation in C. alismatifolia. In the present study, high-quality RNA was extracted from three flowering stages of ‘Dutch Red’ and the blossoming stage of ‘Chocolate’. In all, 576.45 Mb clean data and 159,687 de-redundant sequences were captured. The Kyoto Encyclopedia of Genes and Genomes analysis showed that the pathways of phenylpropanoid biosynthesis, flavonoid biosynthesis, flavone and flavonol biosynthesis, and terpenoid backbone biosynthesis were the most enriched. Thirty unique isoforms were annotated as encoding enzymes or TFs involved in anthocyanin biosynthesis. Further analysis showed that the up-regulation of anthocyanin biosynthesis genes was associated with the red colour formation of ‘Dutch Red’, and their expression was induced at the initial flowering stage. The gene flavonoid 3′, 5′-hydroxylase, a key enzyme in the formation of delphinidin-based anthocyanins, reduced expression in ‘Chocolate’. In addition, we identified totally 14 TFs including 11 MYB proteins and 3 WD proteins, which might play important roles in the regulation of anthocyanin biosynthesis. The quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results were generally consistent with the high-throughput sequencing results. Together, the results of our study provide a valuable resource for the regulatory mechanism of anthocyanin biosynthesis in C. alismatifolia and for the breeding of Curcuma cultivars with novel and charming flower colours.

The global population of older people grows systematically and with age, the physical and cognitive abilities of people decline. The amount of evidence that gardening may provide substantial health benefits and enhance the quality of ageing is increasing. This paper presents a systematic review of the therapeutic effects of horticulture and gardening on clients aged ≥60 years. It encompasses articles published in English between January 1, 2010, and December 31, 2021. The literature survey shows that the interest in the topic has grown significantly in recent years as over half of the published studies are from 2019 to 2021. Most of this work was done in Asia (60%), America, Europe, Australia and New Zealand. The most commonly used interventions were active horticultural therapy programs or gardening, but 20% of the studies explored the passive connection of being outside. The fitness of the elderly was measured using 33 psychological tests, 32 physiological and functional parameters and different kinds of self-developed questionnaires and interviews. The most commonly used psychological tests were the Geriatric Depression Scale, Self-rated Health and Quality of Life, Mini-Mental State Examination, Friendship Scale, Lubben Social Network Scale, and the Attitudes to Ageing Questionnaire. The physiological and functional parameters included heart rate variability, blood pressure, electroencephalography, brain nerve growth factors, and different types of biomarkers. The study outcomes demonstrated positive results of horticultural therapy on human health and well-being, particularly in a psychological dimension and to a smaller but still significant extent physiological aspect.

In recent years, there has been increasing interest in floral volatiles due to their important function in reproduction, self-protection and so on. Although some progress was made on deciphering emissions of floral volatiles and on related mechanisms under a variety of environmental factors, the effects of Zn²⁺ concentrations on mitochondrial function and floral volatile emissions are yet to be revealed. Dendrobium huoshanense petals were used as materials and were treated with a 0–8 mM ZnSO₄ solution. Intracellular Zn²⁺ concentrations were evaluated by the fluorescent dye method and atomic absorption method. Mitochondrial respiratory chain complex activities and the precursor and ATP contents were determined by the biochemical method. Floral volatile components were analyzed by the gas chromatograph-mass spectrometer (GC-MS). The results indicated that ZnSO₄ application significantly increased intracellular Zn²⁺ concentrations. Elevated intracellular Zn²⁺ concentrations differently affected mitochondrial respiratory chain complex activities, precursor and adenosine triphosphate (ATP) productions and floral volatile emissions. Moreover, positive correlations exist among the activities of mitochondrial respiratory chain complexes, productions of precursors and ATP and emissions of floral volatiles. It is concluded that Zn²⁺ concentrations induce the activity changes of mitochondrial respiratory chain complexes, especially complex II and V, which promote or inhibit the emissions of floral volatiles by affecting the precursor and ATP levels that are closely related to the production of terpenoids, benzoids and fatty acid derivatives. The research will contribute to understanding the relationship between Zn²⁺ concentrations and floral volatile emissions from the perspective of mitochondrial function.