Cassava production in Amazonas state deserves to be highlighted due to its great historical, social, and economic importance. Weed competition severely constrains cassava production in Amazonas. The use of cover crops is safe and very efficient at eliminating weeds while keeping the soil covered. The objective of this study was to evaluate physical properties of soil and glyphosate residues in storage roots as a function of the weed management in cassava. The experiment was carried out in a randomized complete block design with five treatments and five repetitions. The treatments were biological control with two species of cover plants (Brachiaria ruziziensis and Mucuna pruriens), chemical control, mechanical control, and treatment with no weed control. The cover crops characteristics evaluated were dry weight, the percentage of cover, and rate of decomposition of plant residues. In the soil, the bulk density and total porosity were determined. The contamination of the storage roots was evaluated based on the analysis of glyphosate residue. Brachiaria ruziziensis presented more dry weight and higher percentage of cover compared with M. pruriens, and both cover crops showed very similar decomposition rates. The physical properties of soil were unaffected by any treatment evaluated. There was no detection of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in any treatment evaluated. Chemical control with glyphosate is not able to contaminate cassava storage roots.
Daniel Oscar Pereira Soares, Karla Gabrielle Dutra Pinto, Laís Alves da Gama, Carla Coelho Ferreira, Prasanta C. Bhowmik, and Sônia Maria Figueiredo Albertino
Li Xiang, Lei Zhao, Mei Wang, Junxia Huang, Xuesen Chen, Chengmiao Yin, and Zhiquan Mao
Apple replant disease (ARD) causes enormous economic loss and threatens the survival of apple industry worldwide. Fusarium solani is one of the pathogens that has been proven to cause ARD. Samples were collected at different time periods to investigate the mechanism of defense responses of apple to F. solani infection by monitoring the biomass, reactive oxygen species (ROS), and antioxidant enzyme activities of the apple rootstock ‘M.9T337’. In addition, the abundance of transcription of four pathogenesis-related (PR) proteins involved in antifungal defense was monitored. The results showed that the apple root system was normal and had small brown areas. However, there is a rapid burst of ROS during the early infection stage, and the activities of antioxidant enzymes and transcription of PRs increased during this period. With the extension in infection time, the infected root tissues displayed dark brown necrosis, and the activities of antioxidant enzymes and abundance of transcription of PRs decreased gradually after reaching their peak. Eventually, the plant biomass decreased, and the plant died. In conclusion, the levels of ROS and activities of antioxidant enzymes played an active role during the early stage of resistance of ‘M.9T337’ apples to infection by F. solani. Infection by F. solani can destroy the ROS scavenging system, causing oxidative damage and inhibiting the growth of apple rootstocks.
Nan Tang, Wuhua Zhang, Liwen Chen, Yan Wang, and Daocheng Tang
Marigold (Tagetes erecta) is an important commercial plant because of its ornamental, industrial, and medicinal values. Male-sterile two-type lines are important for heterosis utilization and breeding of marigold. Mining of fertility-related genes may help to elucidate the mechanisms underlying male sterility. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) is a popular and useful tool for analyzing the expression level of a specific gene. Notably, identifying a suitable reference gene is important for data normalization because it affects the accuracy of quantitative analysis. However, at present, no reference genes are available for marigold. During the current study, 10 candidate reference genes were selected and their expression levels in different samples were analyzed by qRT-PCR. The expression level of each gene was analyzed across different developmental stages of male-sterile and male-fertile flower buds by four software programs (geNorm, NormFinder, BestKeeper, and RefFinder). The results showed that different reference genes are required for male-sterile and male-fertile samples, even if they belong to the same line. For male-sterile samples, the ribosomal protein S5/18S ribosomal RNA (RPS5/18S) gene pair was the best reference for qRT-PCR normalization, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) could be used as an alternative. For male-fertile samples, elongation factor 1-alpha (EF1α) and RPS5 were the most suitable reference genes, and Ubiquitin-conjugating enzyme (UBC) could be used as an alternative. Beta-actin (ACTB), tubulin beta (TUB), and phenylalanine ammonia-lyase (PAL) should not be used as reference genes because they were the most unstable genes in flower buds of marigold. The results of the current study may facilitate the selection of reference genes for analyzing the expression patterns of genes involved in flower development related to male sterility in marigold.
Gerald Henry, Rebecca Grubbs, Chase Straw, Kevin Tucker, and Jared Hoyle
Previous research involving turfgrass response to soil moisture used methodology that may compromise root morphology or fail to control outside environmental factors. Water-table depth gradient tanks were employed in the greenhouse to identify habitat specialization of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] and manilagrass [Zoysia matrella (L.) Merr.] maintained at 2.5 and 5.1 cm. Turfgrass quality (TQ), normalized difference vegetation index (NDVI), canopy temperature (CT), and root biomass (RB) were used as metrics for plants grown in monoculture in sandy clay loam soil. Mowing height did not affect growth of turfgrass species in response to soil moisture. Turfgrass quality, NDVI, and RB were greatest, whereas CT was lowest at wetter levels [27- to 58-cm depth to the water-table (DWT)] of each tank where plants were growing at or above field capacity. However, bermudagrass RB was greatest at 27-cm DWT, whereas manilagrass RB at 27-cm DWT was lower than RB at 42.5- to 73.5-cm DWT in 2013 and lower than all other levels in 2014. Both species responded similarly to droughty levels (120- to 151-cm DWT) of the tanks. Turfgrass quality, NDVI, and RB were lowest, whereas CT was highest at higher droughty levels. Bermudagrass may be more competitive than manilagrass when soil moisture is high whereas both species are less competitive when soil moisture is low.
Derek J. Plotkowski and John A. Cline
Insufficient biologically available nitrogen (N) for yeast is a persistent issue facing cidermakers, whose apple juice base usually does not provide adequate nutrition for a complete fermentation. Cidermakers often supplement their juice with additional yeast assimilable nitrogen (YAN) in the cellar to aid fermentation. The development of biologically available N in apple juice is not well understood. In this study, juice samples from ‘Crimson Crisp®’ apples were taken at several sampling dates in the 2016, 2017, and 2018 growing seasons and analyzed for YAN using formol titration and high-performance liquid chromatography. It was observed that while the total YAN concentration in these apples drops from the period shortly after fruit set to the end of summer, YAN remains stable from several weeks before harvest until the date of harvest. The total YAN did not change after a 6-week postharvest storage period. By contrast, the individual amino acid components of YAN do change during this period. This experiment shows that foliar urea sprays in ‘Crimson Crisp®’ produce an increase in organic N in the juice, mostly in the form of asparagine. Increased organic N impacts yeast growth and sensory characteristics of cider and may be seen as desirable by cider producers.
Carolina Font i Forcada, Gemma Reig, Christian Fontich, Ignasi Batlle, Simó Alegre, Celia M. Cantín, Iban Eduardo, Joaquim Carbó, Arsène Maillard, Laurence Maillard, and Joan Bonany
Hui He, Tingting Li, Fan Zhou, Qianjun Yang, Luyun Hu, and Yanwei Yu
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.
Michael Alden and James E. Faust
The effects of day temperature (DT), night temperature (NT), and night length (NL) were evaluated on the flowering responses of heat-tolerant and heat-sensitive poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) cultivars Orion Red and Prestige Red, respectively. Plants were placed under 60 DT × NT × NL treatments that consisted of three DT (20, 24, 28 °C), four NT (16, 20, 24, 28 °C), and five NL (10, 11, 12, 13, 14 hours) for the first 17 days of the experiment. After 17 days, all plants were consolidated to one greenhouse with an inductive environment (14-hour NL, 24 ± 2.0 °C DT and 21.2 ± 1.4 °C NT), and the timing of first color, visible bud, and anthesis were recorded. ‘Orion Red’ reached anthesis 8 to 10 days faster than ‘Prestige Red’ across all NLs; however, in both cultivars, days to anthesis decreased in a sigmoidal pattern as NL increased. The relative rate of progress to anthesis (1/days to anthesis) under a 12-hour NL was approximately half that of plants grown at a 13- or 14-hour NL. At a 12-hour NL, the relative rate of progress to anthesis decreased linearly as DT increased for both cultivars. At 13- to 14-hour NL, DT had relatively little effect on the relative rate of progress to anthesis. Thus, high DT delayed flowering of both heat-tolerant and heat-sensitive cultivars when flower initiation occurred under NL, typical of naturally occurring NLs in September and early October (i.e., 12-hour NL), whereas high DT did not delay flowering for either cultivar under a 14-hour NL, which is typically provided under black cloth systems. In contrast, the flowering responses to NT were quite different for the two cultivars. The heat-tolerant cultivar showed relatively little change in the relative rate of progress to anthesis as NT increased from 16 to 28 °C within each NL treatment; however, the heat-sensitive cultivar displayed a large decrease in the relative rate progress to anthesis as NT increased from 20 to 28 °C within each NL treatment. Although the delayed flowering that occurred at 28 °C and 14-hour NL was significant, the relative rate of progress to anthesis at this treatment was significantly higher than the 28 °C and 12-hour NL treatment. This suggests that artificially shortening NL to 14 hours with a black cloth system does not prevent heat delay of poinsettia, but it allows for more rapid flowering than if flower initiation took place under natural NL (≈12 hours). To summarize, high DT affected flowering when flower initiation took place at 12-hour NL for heat-tolerant and heat-sensitive poinsettia cultivars, whereas high NT uniquely delayed flowering of the heat-sensitive cultivar at NL from 12 to 14 hours.
Catherine E. Belisle, Steven A. Sargent, Jeffrey K. Brecht, Germán V. Sandoya, and Charles A. Sims
The postharvest life of lettuce (Lactuca sativa) is variable and negatively affected by mechanical injury, incomplete cooling, and poor genetic quality. Lettuce breeders are developing cultivars with a longer shelf life and rely on subjective, destructive, and time-consuming methods for quality analysis. One method of accelerating quality evaluations is known as accelerated shelf-life testing (ASLT), which has the potential to assist breeders in assessing lettuce quality and shelf life. The objective of this research was to determine the quality traits that significantly affect shelf life to develop an ASLT procedure to rapidly assess the postharvest quality of lettuce accessions in breeding programs. In Test 1, Romaine lettuce quality was evaluated using one subjective and five objective parameters during storage at 5, 10, 15, or 20 °C. Results determined that weight loss, lightness*, and hue* angle were best correlated with the overall appearance rating, whereas storage at 10 or 15 °C differentiated the shelf-life potential quickly and without excessive deterioration. In Test 2, these objective characteristics and storage temperatures were used to study rates of quality deterioration of a commercial Romaine cultivar (Okeechobee) and a breeding line (60182), both with long shelf lives, and a Batavia lettuce cultivar (La Brillante) with a short shelf life. Lettuce was evaluated during storage at 10 °C (winter and spring seasons) or at 15 °C (winter season). Weight loss was the most appropriate quality index for lettuce at these storage temperatures for a single harvest, whereas lightness* and hue* angle were the most appropriate indices for comparing quality between harvests. To apply ASLT to postharvest assessments of lettuce, breeders and other researchers should include two controls with good and poor shelf life (similar to ‘Okeechobee’ and ‘La Brillante’, respectively) as standard baseline cultivars during storage at either 10 or 15 °C.