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  • Author or Editor: Fan Li x
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The responses of photosynthesis, chlorophyll fluorescence, and de-epoxidation state of the xanthophyll cycle pigments (DEPS) of micropropagated apple trees (Malus ×domestica) were investigated under whole-root water stress (WRS) and half-root water stress (HRS) induced by polyethylene glycol 6000 to simulate whole and partial root zone drying. Compared with control plants without water stress, plants under WRS and HRS exhibited reduced leaf net photosynthetic rate (Pn) and stomatal conductance (g S) with a greater reduction in WRS than in HRS plants. However, intercellular CO2 concentration (Ci) increased under WRS as water stress was prolonged, signifying a non-stomatal limitation of Pn. Regarding HRS, decreased Pn was mainly the result of a stomatal limitation explained by a relatively low Ci. Changes in photosynthesis and chlorophyll parameters indicate that severe and slight damage occurred to the photosynthetic apparatus of WRS and HRS leaves, respectively, starting at Day 3 after initiating water stress. This damage was not evident on the donor side but was expressed as a reduced capacity of the acceptor side of the photosystem II reaction centers. To prevent damage from excess light, the DEPS of WRS leaf increased. Decreased g S could explain reduced water use under an irrigation strategy of partial root zone drying in fruit trees.

Free access

Chinese wild Vitis is a useful gene source for resistance to biotic and abiotic stresses, although there is little research on its genetic diversity and structure. In this study, nine simple sequence repeat (SSR) markers were used to assess the genetic diversity and genetic structure among 100 Vitis materials. These materials included 77 indigenous accessions representing 23 of 38 wild Vitis species/cultivars in China, 18 V. vinifera cultivars, and the five North American species V. aestivalis, V. girdiana, V. monticola, V. acerifolia, and V. riparia. The SSR loci used in this study for establishing an international database (Vitis International Variety Catalogue) revealed a total of 186 alleles in 100 Vitis accessions. The mean values for the gene diversity (GD) and polymorphism information content (PIC) per locus were 0.91 and 0.90, respectively, which indicates that the discriminatory power of the markers is high. Based on the genetic distance data, the 100 Vitis accessions were divided into five primary clusters by cluster analysis, and five populations by structure analysis; these results indicate these Chinese wild grapes were more genetically close to European grapes than to North American species. In addition, the clustering patterns of most accessions correlated with the geographic distribution. An analysis of molecular variance (AMOVA) revealed that 3.28%, 3.27%, and 93.46% of the variance occurred between populations, between individuals within populations, and between individuals within the entire population, respectively. In addition, we identified three previously undescribed accessions (Wuzhi-1, MZL-5, and MZL-6) by cluster analysis. Our results reveal a high level of genetic diversity and variability in Vitis from China, which will be helpful in the use of genetic resources in future breeding programs. In addition, our study demonstrates that SSR markers are highly suitable for further genetic diversity analyses of Chinese wild grapes.

Open Access

In ‘Beijing 24’ peach [Prunus persica (L.) Batch] trees, a series of source leaves with differing levels of end products were created by retaining fruit (“+fruit”), removing fruit (“−fruit”), or reducing the light period. To alter the light period, leaves were covered with a bag made of brown inner paper and outer silver paper, which was then removed at different times the next day. The highest level of end products were obtained by fruit removal, while reducing the light period resulted in a lower level than “+fruit.” Net photosynthetic rate (Pn) and stomatal conductance (g s) decreased, but leaf temperatures (Tleaf) increased, following an increase in end product levels in leaves. After the “−fruit” treatment, reduced Pn was correlated with lower g s, and Tleaf increase was concomitant with decreases in maximal quantum yield of photosystem II (Fv/Fm), actual photochemical efficiency of photosystem II (ΦPSII), and photochemical quenching, and with an increase in nonphotochemical quenching. However, there were no significant differences in chlorophyll fluorescence between “+fruit” and the two treatments reducing the light period. The ΦPSII decreased following an increase in foliar sorbitol level, and it linearly decreased as sucrose and starch increased. Although fruit removal resulted in a significant accumulation of sucrose, sorbitol, and starch in leaves throughout the day, the extractable activities of several important enzymes involved in carbohydrate leaf storage and translocation did not decrease. Therefore, instead of feedback regulation by the accumulation of end products in source leaves, a high Tleaf induced by decreased stomatal aperture may play a key role in regulation of photosynthesis by limiting the photochemical efficiency of the PSII reaction centers under high levels of the end products in peach leaves.

Free access

Kalanchoe (Kalanchoe blossfeldiana) is a common potted flower that is popular throughout the world. Brown spot (caused by Stemphylium lycopersici) is one of the common foliage diseases in kalanchoe. This disease tends to infect leaves of kalanchoe plants in hot and humid environments, reducing their aesthetic value. The current investigation aimed to generate mutations resistant to brown spot in ‘Mary’ kalanchoe through chemical mutagenesis followed by molecular marker identification. Putative mutants were developed by treating embryogenic calluses with ethyl methanesulfonate (EMS) at median lethal doses (LD50)–either a 0.8% concentration for 2 hours or a 1.0% concentration for 0.5 hours. Brown spot crude toxin solution was used as the selection agent to identify disease-resistant calluses during tissue culture. The optimal crude concentration (60%) was determined by soaking calluses with different concentrations of crude pathogen: 0%, 20%, 40%, 60%, and 80% (v/v). A total of 32 anti-brown spot lines were regenerated and tested for disease resistance with detached leaves. Three regenerated EMS mutant lines showed no obvious brown spot lesions on their leaves after the disease resistance assay and were subjected to polymorphism identification by start codon targeted (SCoT) molecular markers. Three (SCoT40, SCoT71, and SCoT72) of 45 selected primers were chosen to identify the mutants. This work may lay the foundation for further development of new disease-resistant cultivars of kalanchoe.

Free access

We investigated the effects of different planting seasons and gibberellic acid treatments on the growth and development of Gypsophila paniculata to explore new approaches to controlling the flowering period. Four different cultivars were selected and continually planted in July, September, and November in the low-latitude and high-altitude region of Kunming, China (25° N, 102° E). Results showed that the vegetative growth and flowering time of Gypsophila paniculata were prolonged and postponed when the planting time was delayed. Specifically, ‘My Pink’ showed 20% and 80% rosette rates when grown in autumn and winter, respectively, thus indicating that Gypsophila paniculata is sensitive to planting time. Moreover, GA3 treatment not only can significantly promote vegetative growth but also can stimulate early flowering and suppress the occurrence of rosettes during winter. This is more specific to ‘My Pink’, which showed 40% and 80% reductions in rosette rates with four and eight GA3 treatment applications, respectively. Our study showed that seasonal variations in the growth and development of Gypsophila paniculata and GA3 treatment can effectively stimulate early flowering and suppress rosettes during winter.

Free access

Gypsophila paniculata is an ornamental crop with medicinal value. To date, limited information has been reported about the natural products in G. paniculata to explain its medicinal function. The current study reports the natural products found in G. paniculata stem for the first time. Thirty-three compounds were isolated from the extract of G. paniculata stem and identified by gas chromatography-mass spectrometry, 10 of which have contents >2%. These were 2-O-methyl-D-mannopyranose (37.4706%), glycerol (12.5669%), two tetratetracontane isomer (7.6523 + 3.5145%), tetrahygro-4-pyranol (5.3254%), 1,6-anhydro-beta-d-glucopyranos (4.7507%), palmitic acid (4.1848%), 4-hydroxy-3-methoxystyrene (3.7439%), methyl-octadeca-9,12-dienoate (2.7490%), and 2-deoxy-D-galactose (2.6193%). Another bioactive compound, condrillasterol, was identified with 1.3384% content. We also reported that G. paniculata possesses antioxidant activity possibly associated with the presence of a phenolic chemical 4-hydroxy-3-methoxystyrene. Our data collectively demonstrate that G. paniculata contains some bioactive compounds with high contents and antioxidants, consistent with its role as a medicinal herb.

Open Access

Strawberry ‘Tokun’ (2n = 10x =70) is a unique cultivar with special flavors, but its late maturity hampers its extension. To advance flowering and fruiting of this decaploid strawberry, the effects of short-day combined with extra nitrogen (N) nutrition treatments on strawberry ‘Tokun’ plants were studied. Runner plantlets of strawberry ‘Tokun’ were harvested and rooted in tray plugs in June 2016, 2017, and 2018, and established plants were conditioned with short-day (SD; 10 hours) and extra N nutrition. The conditioned plants were transplanted into a tabletop substrate culture system in a plastic greenhouse on 27 Aug., 3 Sept., and 10 Sept. during the 3 years, respectively, and the plants received full-element nutrient solution through the drip tube during the whole experimental period. The number of runners and lateral buds, flowering and fruiting periods, and fruit yield were investigated. Longer duration (6–7 weeks) of the SD treatment (10 hours) could significantly reduce the number of runners and increase the number of lateral buds of strawberry ‘Tokun’, advance flowering and fruiting, and achieve a fruit yield of ≈200 g/plant from November to December. The positive effect of extra N nutrition on flowering and fruiting of strawberry ‘Tokun’ was not found. This study is of great practical importance and guiding significance for cultivation and extension of the decaploid strawberry ‘Tokun’.

Open Access

Extrapyramidal symptoms (EPSs) are common adverse reactions to antipsychotics in patients with schizophrenia. The purpose of this study was to investigate the effects of edible horticultural therapy (EHT) on EPSs in schizophrenic patients. This study assessed the changes in psychopathological symptoms and extrapyramidal symptoms in patients with schizophrenia before and after participating in a six-session EHT. Forty schizophrenic patients, recruited from Wuhan Wudong Hospital, were randomly assigned to the EHT group (average age: 45.40 ± 13.960 years) or the control group (average age: 49.30 ± 12.516 years). The EHT program held weekly sessions from May 2020 to June 2020. A psychiatrist assessed the psychopathological symptoms and extrapyramidal symptoms of schizophrenic patients in both groups with the Chinese version of the Positive and Negative Syndromes Scale (PANSS) and the Rating Scale for Extrapyramidal Side Effects (RSESE). After six courses of horticultural therapy, the terms of positive, negative, and general symptoms on the PANSS significantly improved in the EHT group. Moreover, the EPSs were also significantly improved in the EHT group. However, there was no change in the PANSS and RSESE scores in the control group. This study shows that EHT has the potential to improve not only psychopathological symptoms but also EPSs in psychiatric patients. This adds new evidence for EHT as an adjunct to treatment for schizophrenia.

Open Access