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An experiment was conducted to measure the effects of pulse treatments of BA, sucrose, and BA before, after, or with sucrose, on the vase life of cut Eustoma flowers. A BA pulse at 50 mg·L-1 before 4% sucrose promoted the longevity of cut Eustoma flowers better than other treatments. Simultaneously, sucrose, glucose, and mannose concentrations in flowers during vase periods were maintained at higher levels in double pulse treatments than in the single pulses. Ethylene production in flowers 2 days after vase treatment was highest in the BA-treated flowers; intermediate in flowers pulsed with BA before, after, or with sucrose; and lowest in sucrose-treated flowers. Although a BA pulse increased ethylene production over that of controls, it inhibited senescence in cut Eustoma flowers. Respiration in flowers pulse-treated with sucrose or with BA before, after, or with sucrose, was significantly higher than that in controls. Results suggest that the vase life of cut Eustoma flowers is improved by either BA or sucrose in vase solution and especially when BA was pulsed before the sucrose pulse. Chemical name used: N6-benzyladenine (BA).
Tall fescue is an important cool-season grass widely used for forage and turf, and its genotypic variation for morphological traits has not been well documented. One hundred and fifteen tall fescue accessions, including 25 commercial cultivars, were divided into five groups based on their origination. The morphological traits, including plant height, spike length, pulvinus distance, spikelet count, branch count per spike, spike count per plant, and spike weight in different accessions were determined under field conditions in 2013 and 2014. There was significant genotypic variation in morphological traits among the 115 tall fescue accessions. Wild accessions exhibited a greater variation in the morphological traits than commercial cultivars. Close correlations were found among plant height, spike length, pulvinus distance, and spikelet count. The results of this suggest plant height, spike length, pulvinus distance, and spikelet count could be used as key morphological traits for evaluating all fescue germplasm effectively.
Bermudagrass [Cynodon dactylon (L.) Pers.] is a warm-season turfgrass that has the potential to improve saline and alkaline soils. However, its utilization is severely limited by high salinity. Therefore, it is urgent to enhance its tolerance to salt stress. Previous studies have proved that nitric oxide (NO) plays a vital role in various biological processes. However, the role of NO in bermudagrass response to salt is unknown. Our objective here was to investigate whether and how NO contributes to the protection of bermudagrass against salt stress in bermudagrass. In this study, sodium nitroprusside (SNP) served as the NO donor, while 2-phenyl-4,4,5,5-tetramentylimidazoline-l-oxyl-3-xide (PTIO) plus NG-nitro-L-arginine methyl ester (L-NAME) acted as the NO inhibitor. The treatment of bermudagrass with 400 mm salt solution occurred under different regimes: control, SNP, PTIO + L-NAME (PL). The results showed that 400 mm salinity caused significant toxicity to bermudagrass. However, SNP alleviated damage effect on plant growth and ionic balance as indicated by higher water content, chlorophyll content, higher chlorophyll a fluorescence (OJIP) curves and K+:Na+, Mg2+:Na+, and Ca2+:Na+ ratios. Also, lower levels of electrolyte leakage, malonaldehyde, H2O2, superoxide dismutase, peroxidase, and ascorbate peroxidase activities suggested that NO reduced the membrane injury and lipid peroxidation under salt treatment, while PL regime showed severe damage. In summary, our results suggest that NO has some beneficial effects on the maintenance of cell membrane stability, alleviation of oxidative damage and maintenance of ion homeostasis and plant photosythesis when bermudagrass is exposed to high salinity condition.
Camellia is one of the four main oil-bearing trees along with olive, palm, and coconut in the world. Known as “Eastern Olive Oil,” camellia oil shares similar chemical composition with olive oil, with high amounts of oleic acid and linoleic acid and low saturated fats. Camellia was first exploited for edible oil in China more than 1000 years ago. Today, its oil serves as the main cooking oil in China’s southern provinces. Introduction of camellia oil into the Western countries was delayed until the recognition of its many health benefits. Although popularity for the oil has yet to grow outside of China, interest has emerged in commercial production of camellia oil in other countries in recent years. Unlike seed-oil plants that are grown on arable land, oil camellias normally grow on mountain slopes. This allows the new crop to take full usage of the marginal lands. To facilitate promoting this valuable crop as an alternative oil source and selecting promising cultivars for targeted habitats, this paper reviews the resources of oil camellias developed in China, use of by-products from oil-refining process, as well as the progress of developing camellias for oil production in China and other nations.
High-frequency somatic embryogenesis and plant regeneration were achieved from immature cotyledonary-stage embryos in the endangered plant, Tapiscia sinensis Oliv. Plant growth regulators with different concentrations and combinations on embryogenesis capacity were studied. The optimal explants for in vitro somatic embryogenesis were immature embryos in T. sinensis. A high callus induction rate of 100% was achieved on Murashige and Skoog (MS) basal medium supplemented with 1.0 mg·Ll−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5% (w/v) activated charcoal. Alternatively, a high induction rate (96.16%) of somatic embryogenesis was obtained on MS basal medium supplemented with the combination of 0.05 mg·L−1 α-naphthaleneacetic acid (NAA) and 0.2 mg·L−1 6-benzylaminopurine (6-BA), and somatic embryos proliferated fastest on the mentioned medium supplemented with 0.5% (w/v) activated charcoal and 3% (w/v) sucrose, inoculation of explants proliferating 21 times in the 23-day subculture. Of the 100 plantlets transferred to field after the acclimation, 95 (95%) survived. Based on the histocytological observations, the development of somatic embryos was similar to that of zygotic embryos. There were two accumulation peaks of starch grains in the embryogenic calli and in the globular-stage embryos, both closely related to the energy supply, and the embryoids were of multicelluar origin.
Chrysanthemums have beautiful flowers with high ornamental value and rich genetic diversity. Amplified fragment length polymorphism (AFLP) markers were used to detect the relationships among 12 wild accessions and 62 groundcover chrysanthemum cultivars. Nineteen EcoRI/MseI primer combinations revealed 452 informative polymorphic bands with a mean of 23.8 bands and 71.5% polymorphic rate per primer pair. Jaccard’s coefficient of similarity varied from 0.64 to 0.89, indicating much genetic variation in chrysanthemums. The 74 accessions were classified into two major groups by unweighted pair group method with the arithmetic averages (UPGMA). The dendrogram showed that AFLP variability was closely correlated with both geographic distribution and traditional classification of the wild accessions. Among all accessions, genetic relationship was the most relevant factor in AFLP-marker clustering, whereas petal type was also informative. AFLP technology could be very efficient for discriminating species of chrysanthemum and its related genera and reconstruct their genetic relatedness.
We investigated the FT/TFL1 family of peach (Prunus persica), a gene family that regulates floral induction in annual and perennial plants. The peach terminal flower 1 gene (PpTFL1) was expressed in a developmental and tissue-specific pattern that, overall, was similar to that of TFL1 orthologs in other woody Rosaceae species. Consistent with a role as a floral inhibitor, ectopic expression of PpTFL1 in arabidopsis (Arabidopsis thaliana) delayed flowering and prolonged vegetative growth. Other members of the peach FT/TFL1 family were identified from the sequenced genome, including orthologs of flowering locus T, centroradialis, brother of ft, and mother of ft and tfl. Sequence analysis found that peach FT/TFL1 family members were more similar to orthologous genes across the Rosaceae than to each other. Together these results suggest that information on genes that regulate flowering in peach could be applied to other Rosaceae species, particularly ornamentals.
Bermudagrass (Cynodon dactylon) is a typical and widely used warm-season turfgrass. Low temperature is one of the key environmental stress limiting its utility. However, little information is available about the differences of cold response between bermudagrass genotypes. Here, we analyzed antioxidant defense system and fatty acid composition in cold-resistant genotype WBD128 and cold-sensitive genotype WBDg17 exposed to chilling stress. Low temperature (4 °C) significantly decreased the relative water content, whereas increased the H2O2 and O2 − contents, more profoundly for WBDg17. Under chilling condition, WBD128 had higher anti O2 − activity than WBDg17. Besides, the contents of total glutathione, reduced glutathione (GSH) and its oxidized form (GSSG) were markedly increased by low temperature in both genotypes, whereas WBD128 had significantly higher values of GSH, total glutathione, and GSH/GSSG ratio than WBDg17. Moreover, chilling stress increased saturated fatty acids (SFAs) percentage (palmitic acid and stearic acid) in WBDg17. After chilling treatment, the proportion of linoleic acid decreased in both genotypes, particularly in WBDg17. As for unsaturated fatty acids (UFAs), the percentage of linolenic acid was increased in WBD128. In addition, chilling treatment decreased the values of double bond index (DBI), UFA/SFA ratio as well as degree of unsaturation in WBDg17. Finally, chilling stress altered the expression patterns of the genes, which encode one kind of late embryogenesis abundant proteins (LEA), superoxide dismutase (Cu/Zn SOD) C-repeat-binding factor/DRE-binding factor (CBF1), and peroxidase (POD-2). Collectively, our results revealed that natural variation of chilling tolerance in bermudagrass genotypes may be largely associated with the alterations of antioxidant defense system and fatty acid composition.
Cold stress is a key factor limiting resource use in bermudagrass (Cynodon dactylon). Under cold stress, bermudagrass growth is severely inhibited and the leaves undergo chlorosis. Therefore, rigorous investigation on the physiological and molecular mechanisms of cold stress in this turf species is urgent. The objective of this study was to investigate the physiological and molecular alteration in wild bermudagrass under cold stress, particularly the changes of transpiration rate, soluble sugar content, enzyme activities, and expression of antioxidant genes. Wild bermudagrass (C. dactylon) was planted in plastic pots (each 10 cm tall and 8 cm in diameter) filled with matrix (brown coal soil:sand 1:1) and treated with 4 °C in a growth chamber. The results displayed a dramatic decline in the growth and transpiration rates of the wild bermudagrass under 4 °C temperature. Simultaneously, cold severely destabilized the cell membrane as indicated by increased malondialdehyde content and electrolyte leakage value. Superoxide dismutase and peroxidase activities were higher in the cold regime than the control. The expression of antioxidant genes including MnSOD, Cu/ZnSOD, POD, and APX was vividly up-regulated after cold stress. In summary, our results contributed to the understanding of the role of the antioxidant system in bermudagrass’ response to cold.
The application of diffuse light can potentially improve the homogeneity of light distribution and other microclimatic factors such as temperature inside greenhouses. In this study, diffuse light plastic films with different degrees of light diffuseness (20% and 29%) were used as the south roof cover of Chinese solar greenhouses to investigate the spatial distribution of microclimatic factors and their impacts on the growth and yield of tomato. The horizontal and vertical photosynthetic photon flux density (PPFD) distributions, air temperature distribution, and leaf temperature distribution inside the canopy, tomato leaf net photosynthesis (Pn), and fruit production during the growth period were determined. The results showed that diffuse light plastic film continuously improved the light distribution in the vertical and horizontal spaces of the crop canopy in terms of light interception and uniformity. A more diffuse light fraction also decreased the air and leaf temperatures of the middle canopy and upper canopy during the summer, thereby promoting the photosynthesis of the tomato plants. Pn of the middle and lower canopies with higher haze film were significantly greater than those with lower haze film (19.0% and 27.2%, respectively). The yields of higher stem density and lower stem density planted tomatoes in the 29% haze compartment were increased by 5.5% and 12.9% compared with 20% in the haze group, respectively. Diffuse light plastic films can improve the homogeneity of the canopy light distribution and increase crop production in Chinese solar greenhouses.