Search Results

You are looking at 1 - 8 of 8 items for

  • Author or Editor: Zong Liu x
Clear All Modify Search

Abstract

Methods were developed for efficient shoot regeneration from leaf and runner tissues of the strawberry (Fragaria × ananassa) cultivars Allstar and Honeoye. Optimal regeneration conditions differed for ‘Allstar’, depending on whether leaf tissue was derived from plantlets grown in vitro or from plants grown in the greenhouse. ‘Allstar’ leaf tissues derived from in vitro cultures regenerated shoots most efficiently in a Linsmaier–Skoog (LS) medium containing 2.5 mg BA and 0.5 mg IBA/liter. ‘Allstar’ leaf tissues derived from greenhouse plants regenerated shoots best in LS medium containing 3.0 mg BA and 0.1 mg IBA/liter. Addition of casein hydrolysate (CH) at either 400 or 600 mg·liter−1 stimulated shoot production. A supplement of KNO3 at 2000 mg·liter−1 also enhanced regeneration efficiency of greenhouse-grown leaf tissues. ‘Honeoye’ had lower regeneration potential in most treatments than ‘Allstar’ and only produced shoots in a LS medium containing 5.0 mg BA, 0.5 mg IBA, and 400 mg CH/liter. Shoots from runner tissues of both cultivars were best obtained using LS medium containing 10.0 mg BA, 2.0 IAA, and 500 mg CH/liter. Shoot production from runners was dependent on the diameter of the runner, with diameters of <2.0 mm having poor regeneration potential. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); 1H-indoIe-3-butyric acid (IBA); and 1H-indole-3-acetic acid (IAA).

Open Access

Improving the poor resistance to environmental stress and the weak development of roots system in the cherry (Prunus) rootstock ‘Gisela 6’ (Prunus cerasus × Prunus canescens) is of great importance for sustainable sweet cherry (Prunus avium) production. Although a stable genetic transformation system has been developed for ‘Gisela 6’ rootstock, there is little information on the identification of genes involved in stress resistance. Using the cherry rootstock cultivar Gisela 6, we identified a total of 12 novel mitogen-activated protein kinase (MAPK) genes, designated PcMPKs. Phylogenetic analysis revealed that the PcMPKs could be divided into four groups, designated A, B, C, and D. In addition, an intron–exon structure analysis for the PcMPKs was conducted to help further understand the structure–function relationships within the cherry family. The expression profiles of PcMPKs in response to abiotic and biotic stresses were characterized using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Five PcMPKs (i.e., PcMPK4-1, PcMPK4-2, PcMPK3, PcMPK6, and PcMPK18) exhibited differential expression, and suggested their potential roles in plant responding to various stresses. This study provides the basis for further analysis on the physiological functions of PcMPKs in environmental tolerance in cherry rootstocks.

Free access

Waterlogging (WL) negatively affects plant growth and development, but the physiological responses of turfgrass species to WL are not well understood. The objective of this study was to examine growth and physiological mechanisms of WL tolerance in warm-season turfgrass species. Knotgrass (Paspalum paspaloides), spiny mudgrass (Pseudoraphis spinescens), seashore paspalum (Paspalum vaginatum), and centipedegrass (Eremochloa ophiuroides) were subjected to 30 days of WL. At the end of the treatment, knotgrass and spiny mudgrass maintained the shoot and root biomass while seashore paspalum and centipedegrass showed reductions in biomass under WL. Root oxidase activity (ROA) was unaffected until after 12 or 18 days of WL but decreased by 14.3%, 17.8%, 32.0%, and 68.7% at 30 days of WL for knotgrass, spiny mudgrass, seashore paspalum, and centipedegrass, respectively. Waterlogging increased root activities of lactate dehydrogenase and alcohol dehydrogenase, but generally to a lesser extent in knotgrass and spiny mudgrass. The leaf and root activities of superoxide dismutase (SOD) and peroxidase (POD) were induced after 6 or 12 days of WL, but to a greater extent for knotgrass and spiny mudgrass. At 30 days of WL, the increased leaf and root activities of SOD and POD were higher in knotgrass and spiny mudgrass than that of seashore paspalum and centipedegrass; while centipedegrass showed 37.8% reduction in root SOD activity. The total soluble protein (TSP) concentration remained unchanged in both leaves and roots during the entire WL treatment for knotgrass, while a decreased leaf TSP was found in the other three species after 12 or 24 days of WL as well as in the roots of seashore paspalum and centipedegrass. More reductions in leaf or root TSP were observed in seashore paspalum and centipedegrass than in knotgrass and spiny mudgrass at 30 days of WL. The results indicated that higher ROA, activities of antioxidant enzymes and TSP contributed to WL tolerance of warm-season turfgrass species.

Free access

Sugar and organic acid contents as well as sugar-to-acid ratio of fruit are important factors affecting fruit quality and processing. In this study, we compared sugar and organic acid contents of Vaccinium uliginosum (bog bilberry) fruit harvested from 100 plants across 10 wild populations growing in the Changbai Mountains of China. Correlation of sugar and acid contents with the spatial distribution of these populations was accessed. Germplasm with high sugar and low acid with potential for use in future breeding was also identified. Results showed that sugar and organic acid contents varied among different V. uliginosum populations in the Changbai Mountains. Fructose (18.60–38.54 mg·g−1) and glucose (15.77–35.08 mg·g−1) were the main sugars, whereas quinic (16.06–20.97 mg·g−1), citric (10.39–14.96 mg·g−1), and malic (4.28–7.47 mg·g−1) acids were the main organic acids in V. uliginosum. The first population collected in the Dongfanghong forest farm (lat. 42°00′N, long. 128°03′E) showed the highest average sugar content and sugar-to-acid ratio among the sampled populations. Moreover, total sugar content and sugar-to-acid ratio of Sample 7—Population 1, which is located at Manjiang forest farm (lat. 41°09′N, long. 127°05′E) was much higher than the other 99 samples, making this sample representative of important germplasm for breeding. Altitude and latitude were important environmental factors affecting sugar and organic acid contents. Fructose, glucose, and total sugar contents were positively correlated with altitude and negatively correlated with latitude. Oxalic acid content and sugar-to-acid ratio were positively correlated with altitude, and there was no significant correlation between organic acid contents and latitude.

Free access

A static experiment in greenhouse was conducted to investigate the growth of three grasses in high and medium eutrophic water and the effects of their removal on ammonia nitrogen (NH4 +-N), nitrate nitrogen (NO3 -N), total nitrogen (TN), total phosphorus (TP), and the chemical oxygen demand (COD), and compared with cattail (Typha angustifolia). The results showed that 1) the removal efficiency of NH4 +-N, NO3 -N, TN, TP, and COD treated by the four plants in eutrophic water were significantly higher than that in non-plant water. With the extension of treatment time, the concentrations of NH4 +-N, NO3 -N, TN, TP, and COD in the eutrophic water decreased first and then tend to be stable. 2) Cynodon dactylon ‘Tifton 85’ (C. dactylon ‘Tifton 85’), Cortaderia selloana ‘Pumila’ (C. selloana ‘Pumila’) and T. angustifolia absorbed more than 95.7% and 88.6% of TN and TP in eutrophic water, and accumulate more than 89.5% and 82.0% in plants, respectively. However, the ratio of Cortaderia selloana ‘Silver Comet’ (C. selloana ‘Silver Comet’) was significantly lower. 3) The high abilities of these three plants to purify eutrophic water may be directly related to their rapid growth. 4) The comprehensive purification ability of the four plants to eutrophic was significantly different, in the order of C. dactylon ‘Tifton 85’ > C. selloana ‘Pumila’ ≈ T. angustifolia > C. selloana ‘Silver Comet’. These results indicated that C. dactylon ‘Tifton 85’ and C. selloana ‘Pumila’ can be used as alternative plants to T. angustifolia for the purification of eutrophic water. The results of this study can provide new materials and ideas for phytoremediation.

Open Access

This article reports salt-induced changes in leaf and root proteomes after wild tomato (Solanum chilense) plants were treated with 200 mm NaCl. In leaf tissues, a total of 176 protein spots showed significant changes (P < 0.05), of which 104 spots were induced and 72 spots suppressed. Salt-induced proteins are associated with the following pathways: photosynthesis, carbohydrate metabolism, glyoxylate shunt, glycine cleavage system, branched-chain amino acid biosynthesis, protein folding, defense and cellular protection, signal transduction, ion transport, and antioxidant activities. Suppressed proteins belong to the following categories: oxidative phosphorylation pathway, photorespiration and protein translational machinery, oxidative stress, and ATPases. In root tissues, 106 protein spots changed significantly (P < 0.05) after the salt treatment, 63 spots were induced, and 43 suppressed by salt treatment. Salt-induced proteins are associated with the following functional pathways: regeneration of S-adenosyl methionine, protein folding, selective ion transport, antioxidants and defense mechanism, signal transduction and gene expression regulation, and branched-chain amino acid synthesis. Salt-suppressed proteins are receptor kinase proteins, peroxidases and germin-like proteins, malate dehydrogenase, and glycine dehydrogenase. In this study, different members of proteins were identified from leaf and root tissues after plants were subjected to salt treatment. These proteins represent tissue-specific changes in salt-induced proteomes. When protein expression was compared in the context of metabolic pathways, the branched-chain amino acid biosynthesis, glucose catabolism toward reducing cellular glucose level, and the antioxidant, detoxification, and selective ion uptake and transport were induced in both root and leaf tissues. These changes appear to be associated with salt tolerance in the whole plant.

Free access

Three tomato (Solanum lycopersicum) cultivars [Walter LA3465 (heat-tolerant), Edkawi LA 2711 (unknown heat tolerance, salt-tolerant), and LA1310 (cherry tomato)] were compared for changes in leaf proteomes after heat treatment. Seedlings with four fully expanded leaves were subjected to heat treatment of 39/25 °C at a 16:8 h light–dark cycle for 7 days. Leaves were collected at 1200 hr, 4 h after the light cycle started. For ‘Walter’ LA3465, heat-suppressed proteins were geranylgeranyl reductase, ferredoxin-NADP (+) reductase, Rubisco activase, transketolase, phosphoglycerate kinase precursor, fructose–bisphosphate aldolase, glyoxisomal malate dehydrogenase, catalase, S-adenosyl-L-homocysteine hydrolase, and methionine synthase. Two enzymes were induced, cytosolic NADP-malic enzyme and superoxide dismutase. For ‘Edkawi’ LA2711, nine enzymes were suppressed: ferredoxin-NADP (+) reductase, Rubisco activase, S-adenosylmethionine synthetase, methioine synthase, glyoxisomal malate dehydrogenase, enolase, flavonol synthase, M1 family peptidase, and dihydrolipoamide dehydrogenase. Heat-induced proteins were cyclophilin, fructose-1,6-bisphosphate aldolase, transketolase, phosphoglycolate phosphatase, ATPase, photosystem II oxygen-evolving complex 23, and NAD-dependent epimerase/dehydratase. For cherry tomato LA1310, heat-suppressed proteins were aminotransferase, S-adenosyl-L-homocysteine hydrolase, L-ascorbate peroxidase, lactoylglutathione lyase, and Rubisco activase. Heat-induced enzymes were glyoxisomal malate dehydrogenase, phosphoribulokinasee, and ATP synthase. This research resulted in the identification of proteins that were induced/repressed in all tomato cultivars evaluated (e.g., Rubisco activase, methionine synthase, adenosyl-L-homocysteine hydrolase, and others) and those differentially expressed (e.g., transketolase).

Free access