Lilium amoenum is a rare lily germplasm with an agreeable rose fragrance. This study aimed to explore the optimal culture conditions and medium formula for the enlargement of L. amoenum bulblets in vitro. Bulblets of L. amoenum with a diameter of 0.4-0.6 cm were inoculated on Murashige & Skoog (MS) medium supplemented with different concentrations of sucrose or sucrose combined with naphthalene acetic acid (NAA), N-(phenylmethyl)-9H-purin-6-amine (6-BA), indole butyric acid (IBA), or paclobutrazol (PP333). The culture conditions of 16 hours of light/8 hours of darkness and full darkness were set up. After 45 days of culture, the enlargement coefficient and diameter increase multiple of the bulblets were counted. The results showed that in the range of experimental concentrations, with the increase of sucrose and hormone concentrations, the enlargement coefficient and diameter increase multiples of L. amoenum bulblets overall first increased and then decreased. When the sucrose concentration was 50-120 g/L, the bulblet enlargement effect at 90 g/L sucrose was the greatest, and the bulblets were green and shiny, and had good cohesion. When 50-120 g/L sucrose was combined with 0.1-0.7 mg/L NAA/6-BA, 0.5-4.0 mg/L IBA or 5-40 mg/L PP333, the effect of bulblet enlargement was the greatest at 70 g/L sucrose and 1.0 mg/L IBA, and the enlargement coefficient and diameter increase multiple were 3.63 and 1.83, respectively. The synergistic effect of high concentrations of sucrose and PP333 significantly inhibited the enlargement of bulblets. Lilium amoenum bulblets cultured under 16 hours of light/8 hours of darkness grew better than those cultured under full darkness, but the rooting effect was greater under full darkness. This study provides a scientific basis for shortening bulb growth time in the field and for germplasm resource protection.
To explore the roles of heat shock protein 90 (Hsp90) in plant growth development and response to high temperature stress, this study identified the Hsp90 family through bioinformatics methods in the whole genome of Rhododendron ovatum,which is a highly ornamental and widely adaptive species of Rhododendron. Gene structure, cis-acting elements, evolution, and expression pattern of the Hsp90 family were subsequently analyzed. The results showed that 11 members of the Hsp90 family were identified in R. ovatum, which were located on five chromosomes. Cis-acting element analysis showed that all the 11 members of the Hsp90 family were involved in the processes of plant hormone metabolism and stress responses. The phylogenetic tree of Hsp90 family in Arabidopsis thaliana, Solanum lycopersicum, Camellia sinensis, R. simsii, R. delavayi, R. henanense, and R. ovatum was constructed, within four main clades. Evolutionary analysis showed that the Hsp90 family has undergone purification selection during the differentiation of Rhododendron species. Moreover, the expression patterns of Hsp90 family in different tissues and under high temperature treatments indicated that Hsp90 family plays roles in flower development and the response of plants to high temperature stress. This study provides a foundation for further study of the functions of Hsp90 genes in Rhododendron.
In order to explore the molecular mechanism of alkaloid biosynthesis in lotus leaves, metabolomics and transcriptomics sequencing analyses were performed on mature lotus leaves of ‘Taikong Lian’ (high alkaloid content), ‘Juwuba’ (medium alkaloid content) and ‘Dazu Honglian’ (low alkaloid content) cultivars with significant differences in alkaloid content. Metabolomics analysis showed that there were 30, 32 and 14 different metabolites in the three groups of ‘Dazu Honglian’ vs ‘Taikong Lian’ (low vs high alkaloid content), ‘Dazu Honglian’ vs ‘Juwuba’ (low vs medium alkaloid content), and ‘Taikong Lian’ vs ‘Juwuba’ (high vs medium alkaloid content), respectively. These differential metabolites were mainly three types of isoquinoline alkaloids, namely benzylisoquinoline, bis-benzylisoquinoline and aporphine alkaloids, specifically including caaverine, 3′-glucosyl-6, 7-dihydroxy-N-methyl-benzyltetrahydroisoquinoline, dopamine, L-tyramine, etc. To further explore the key genes of the above isoquinoline alkaloid biosynthesis pathway, the transcriptomics sequencing analysis of three cultivars were performed. The numbers of differentially expressed genes (DEGs) among the three groups (‘Dazu Honglian’ vs ‘Taikong Lian’, ‘Dazu Honglian’ vs ‘Juwuba’, and ‘Taikong Lian’ vs ‘Juwuba’) were 2 866, 2 739 and 3 932, respectively; and there were 379 DEGs in common, which contained isoquinoline alkaloid biosynthesis pathway genes. Combined with the results of metabolomics analysis, six key DEGs, including NnCYP80G, Nn6OMT, NnTYDC, NnNCS, NnRAV and NnERF, were finally screened and verified by real-time fluorescent quantitative polymerase chain reaction, which can be used for subsequent gene function verification and molecular regulation network analysis.
To explore the regulation mechanism of TCP4 gene on the development of petal spur of Impatiens uliginosa, the full length cDNA of TCP4 gene in I. uliginosa (named as IuTCP4) was cloned by reverse transcription polymerase chain reaction, and its sequence was analyzed by bioinformatics. Then, real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to investigate the spatiotemporal expression pattern of IuTCP4 gene at different developmental stages and different tissue locations of petal spur. The results showed that the full-length cDNA of two copies (IuTCP4.1 and IuTCP4.2) of TCP4 gene in I. uliginosa were 1 194 bp and 1 173 bp, encoding 397 and 390 amino acids, respectively, and neither contained introns. Both of IuTCP4.1 and IuTCP4.2 encoded proteins were unstable and hydrophilic without signal peptide and transmembrane domain. The homology of amino acid sequences of TCP4 protein between I. uliginosa and other 15 species, such as tea (Camellia sinensis) and balsam pear (Momordica charantia), reached 66.11%. In the phylogenetic tree, IuTCP4.1 and IuTCP4.2 clustered into one branch, suggesting that the two copies of IuTCP4 are paralogous genes. The results of qRT-PCR showed that IuTCP4.1 was differentially expressed between petal spur and limb at both the early stage and blooming stage, with the highest expression quantity in the limb at the early stage; IuTCP4.2 was differentially expressed between petal spur and limb at all three developmental stages, and the highest expression quantity was observed in the petal spur at the early stage. In conclusion, IuTCP4 plays a certain regulatory role in the development of petal spur and mainly functions at the early stage of petal spur development. It is provided a theoretical basis for the development mechanism of petal spur, flower shape improvement and new variety cultivation of Impatiens.
To explore the function and potential applications of heat shock transcription factor (HSF) gene family on heat tolerance of Zizania latifolia of ‘Longjiao No. 2’, twenty-eight HSF proteins were identified and analyzed by bioinformatics methods. The physicochemical analysis showed that the theoretical isoelectric point was 4.77 to 11.63, and the molecular weight was 16.77-101.29 kDa, and the protein length was 239-661 amino acids, and the instability indexes of the whole family were more than 40. The multiple sequence alignment revealed that the DNA-binding domain of HSF protein was highly conserved with a length of about 100 amino acids. The phylogenetic tree of HSF proteins of Z. latifolia, Arabidopsis thaliana, Phyllostachys edulis, and Oryza sativa L. was constructed by MEGA 7.0 and the HSF proteins could be divided into A, B, and C classes. In the HSF family of Z. latifolia, there were 17 members in class A, seven in class B, and four in class C. The expression profiles of HSF genes under the heat stress was analyzed by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR), and the physiological indexes under the heat stress were also measured. The results showed that 14 HSF genes were at high expression levels (the expression levels were increased by more than 10 times) after the heat stress (42 ℃, 12 h). Among them, the expression levels of ZlHSF-04, ZlHSF-12, and ZlHSF-27 were up-regulated most obviously, which increased by 37, 36, and 44 times when compared with the normal temperature treatment (CK), respectively. Moreover, under the heat stress, the leaves became dry and curled with a large area of water loss and chlorosis, and the maximum photochemical efficiency (Fv /Fm) of photosystem Ⅱ was significantly reduced by 49.9% compared with the CK. Besides, the relative electrical leakage (REL), and the contents of malondialdehyde (MDA), proline (Pro), hydrogen peroxide (H2O2) increased significantly by 409%, 97%, 396%, and 99%, respectively. These results lay theoretical foundations for further study of the functions of the HSF gene family under heat stress of Z. latifolia.
Screening of stable reference genes was significant when the real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to study gene expression. To identify the most stable reference genes in tomato induced by different hormones, the leaves of susceptible tomato ‘Moneymaker’ (MM) and resistant tomato inbred line 62579, which were treated with abscisic acid (ABA), methyl jasmonate (MeJA), and salicylic acid (SA) for 0, 24, 48, and 120 h, respectively, were used for qRT-PCR amplification. In the current study, the expression stabilities of eight tomato candidate reference genes, including EF1α, L33, Act, Ubi, GAPDH, UK, CAC, and TIP41, were analyzed using geNorm, NormFinder, and BestKeeper softwares. The results revealed that the average CT values of eight candidate reference genes ranged from 26 to 34. Based on the data from these softwares, L33 and Ubi, L33 and EF1α,as well as EF1α and L33 were considered to be the stably expressed reference genesin tomato induced by ABA, MeJA, and SA, respectively. In conclusion, L33 is the most stably expressed gene among all studied candidate reference genes in tomato induced by different hormones. The most stable reference genes screened in this study will provide a calibration basis for the expression analyses of differential genes and the research on molecular mechanisms in tomato response to exogenous hormone treatments in the future.
Shade net covering is a conventional agronomic practice, which has been widely applied in the production of matcha. The present study used different shade treatments (black, red, blue, and yellow shade net treatments) to alter the light conditions (including light intensity and spectral composition) for the growth of tea plants, and investigated the effects of different shade treatments on the phytohormone levels and transcriptome profiles of the leaves of ‘Fuding white tea’ plants, with taking the tea plants grown under the natural light conditions as the control group (CK). The results showed that blue shade net treatment significantly increased the contents of abscisic acid, gibberellins, auxins, cytokinins, jasmonic acid, and salicylic acid in the tea leaves compared with CK, followed by yellow, black, and red shade net treatments. The transcriptome sequencing results showed that the most abundant number of differentially expressed genes (DEGs) was observed under the black shade net treatment (3 422 up-regulation, and 4 074 down-regulation) compared with CK, subsequently followed by blue shade net treatment (476 up-regulation, and 1 271 down-regulation), and yellow shade net treatment (663 up-regulation, and 994 down-regulation), while the lowest DEGs number was observed under the red shade net treatment (723 up-regulation, and 810 down-regulation). The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that photosynthesis-antenna proteins as well as plant hormone signal transduction were the significantly enriched pathways in the pair of blue shade net treatment and CK. Especially, the expressions of light-harvesting complex and phytohormone biosynthesis-related genes were greatly up-regulated. Thus, shade net treatments could regulate the biosynthesis of phytohormones in tea plants through altering the light condition underneath, and further affect the growth of tea young shoots.
Taking satsuma mandarin (Citrus unshiu Marc.) grown in mountainous areas as the research object, and custom fertilization of farmers (only applying chemical fertilizer, the input amounts of N, P2O5, K2O were 211.5, 180.0, 220.5 kg/hm2, respectively) as the control (CF), different combinations of fertilization with organic matter and chemical fertilizer decrement (DF1: the input amounts of N, P2O5, K2O were 153.0, 63.0, 157.5 kg/hm2, respectively; DF2: the input amounts of N, P2O5, K2O were 180.0, 108.0, 211.5 kg/hm2, respectively) were set to study the effects of drip fertigation on citrus yield, quality, nutrient absorption and soil fertility. The results showed that citrus yields of drip fertigation treatments with DF1 and DF2 increased by 17.5% and 16.4%, respectively, as compared with the control. The drip fertigation treatments with DF1 and DF2 could also increase fruit quality. The total soluble solid content increased by 11.4% and 10.5%, and vitamin C content increased by 26.7% and 13.6%, and the total acid content decreased by 16.2% and 21.6%, respectively, as compared with the control. In addition, drip fertigation treatments could significantly increase the absorption of calcium (Ca), magnesium (Mg) and boron (B) in leaves and fruits, which were higher than those of the control. Drip fertigation treatments also had a great impact on soil pH and soil fertility. The soil pH value of DF1 and DF2 treatments was higher than that of the control, and the organic matter content increased by 27.1% and 20.0%, respectively, and the hydrolysable nitrogen (N) content increased by 88.3% and 105.2%, respectively. The soil exchangeable Ca, exchangeable Mg and available B contents were also significantly higher than those of the control. It can be seen that while saving chemical fertilizer, drip fertigation can improve soil fertility, promote the nutrient absorption and utilization of leaves and fruits, and then increase citrus yield and improve fruit quality. Therefore, drip fertigation is an important measure to reduce chemical fertilizer application, improve quality and efficiency in citrus orchards.
In this study, two acylated flavonol tetraglycosides {quercetin-3-O-[(E)-p-coumaroyl-(1→2)][α-L-arabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside，F1；kaempferol-3-O-[(E)-p-coumaroyl-(1→2)]-[α-L-arabinopyranosyl-(1→3)]-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside，F2} were isolated and purified from Camellia sinensis, and the distribution characteristics of F1 and F2 in different tissues, leaf positions, and tea cultivars were systematically studied through the independent established high performance liquid chromatography (HPLC) method. The effect of light on the contents of F1 and F2, and the dynamic changes in the processing stages of oolong tea were also studied. The results showed that F1 was mainly distributed in tea leaves and stems, and F2 was only present in leaves; neither F1 nor F2 was detected in the roots. With the increase of leaf maturity, the contents of F1 and F2 firstly increased and then decreased. Among the 42 tea cultivars, the contents of F1 and F2 ranged from 0-2.31 mg/g and 0-1.56 mg/g, respectively. F1 had the highest content in ‘Huangjinju’ and was not detected in ‘Benshan’ and ‘Lüyafoshou’ tea cultivars. F2 had the highest content in ‘Huangjinju’ and was not detected in ‘Lüyafoshou’, ‘Jinmian Qilan’, ‘Zhonghuang No. 2’ and ‘Benshan’. Shading experiments were carried out on three tea cultivars, and it was found that the content of F1 in the shading treatment group was significantly reduced, indicating that the light plays a significant role in the formation of F1. The fresh leaves of ‘Fujian Shuixian’ were selected for the processing of oolong tea. The contents of F1 and F2 showed downward trends during the whole processing stages, and the largest decline was observed in the process of fixation, while the smallest was in the process of rotation, which shows that different processing operations have different degrees of influences on the contents of two substances.
In order to screen the optimal combination of functional fertilizers for increasing yield and improving quality in the production of substrate-grown cherry tomatoes, cherry tomato ‘Fragrant Feminine 9’ was used as the material, and seven different combinations of functional fertilizers were set up, including blank control (CK), amino acid (T1), potassium xanthate (T2), alginate (T3), amino acid+potassium xanthate (T4), amino acid+alginate (T5), and potassium xanthate+alginate (T6). The functional fertilizers and nutrient solution were applied by drip irrigation to study the effects of different functional fertilizers on quality, yield and substrate environment of substrate-grown cherry tomatoes. The results showed that compared with CK, the addition of alginate (T3) obviously increased the net photosynthetic rate, intercellular CO2 concentration and yield of cherry tomatoes by 39.97%, 6.61% and 22.32%, respectively. The combination of T4 and T5 functional fertilizers not only significantly increased microbial quantities, and the activities of urease, sucrase, alkaline phosphatase and catalase in the substrate, but also significantly improved the quality and yield of cherry tomatoes, with a yield increase by 20.16% and 12.84%, respectively. It was found that the T5 treatment performed the best by comprehensive evaluation. In conclusion, the substrate environment can be improved, and the fruit quality and yield can be increased by adding 50 mg/L amino acids and 5 mg/L alginate in the nutrient solution to cultivate cherry tomatoes using drip irrigation.
This study attempted to explore the effects of maize plant type and row width on the light environment, chlorophyll content, photosynthetic performance, growth characteristics and yield of ginger under the maize/ginger intercropping mode. A total of eight treatments were set, including two plant types of maize cultivars [expanded cultivar ‘Zhenghong 311’ (ZH 311), and compact cultivar ‘Zhenghong 2’ (ZH 2)], three row widths (2, 3, and 4 m), and two controls (sole cropping of ginger under shading, CK1; sole cropping of ginger without shading, CK2). The results indicated that shading could increase the chlorophyll content of leaves, maintain a low chlorophyll (Chl) a/b ratio, improve the photosynthetic performance of ginger leaves, so as to promote the growth of plant height, stem diameter and branching number, and obtain a high yield. The plant height, stem diameter, branching number, yield, contents of Chl a, Chl b, total chlorophyll and carotenoid, total chlorophyll/carotenoid ratio, net photosynthetic rate, stomatal conductance, and transpiration rate of ginger under the maize/ginger intercropping mode were higher than those of CK2, while the light transmittance of ginger canopy and bottom, Chl a/b ratio, and intercellular CO2 concentration were lower than those of CK2. In summary, the shading effects of maize/ginger intercropping on ginger are significantly different in maize plant type and row width. The expanded maize cultivar with 2 m row width has the best shading effect on ginger.
Taking pepper ‘Bola Hongshuai’, cucumber ‘Jinyan No. 4’ and lettuce ‘Batavia’ as experimental materials, the combinations of three groups of photosynthetic photon flux density (PPFD) [160, 200 and 240 μmol/(m2?s)] and three groups of photoperiod (12, 15, 18 h/d) were set up to form eight groups of different daily light integral (DLI) treatments to study the effects of DLIs of light emitting diode (LED) on the growth of their seedlings. The results showed that the optimal light conditions were PPFD of 160 μmol/(m2?s) with photoperiod of 15 h/d [DLI of 8.6 mol/(m2?d)] for ‘Bola Hongshuai’ pepper seedlings, PPFD of 200 μmol/(m2?s) with photoperiod of 15 h/d [DLI of 10.8 mol/(m2?d)] for ‘Jinyan No. 4’ cucumber seedlings, and PPFD of 200 μmol/(m2?s) with photoperiod of 18 h/d [DLI of 13.0 mol/(m2?d)] for ‘Batavia’ lettuce seedlings. The results provide optimized LED light environment parameters for vegetable seedling production.
Taking the berries of the new grape cultivar ‘Nantaihutezao’ and its maternal cultivar ‘Summer Black’ as experimental materials, the variation rule of volatile characteristic aroma compounds during the berry development processes was compared, and their berry quality indicators such as the mass of berry particles, solid-acid ratio were evaluated. The results showed that ‘Nantaihutezao’ matured about 7 d earlier than ‘Summer Black’. The contents of terpenes and ketones which distributed floral and fruity aroma in ‘Nantaihutezao’ were significantly higher than those in ‘Summer Black’, which increased by 162% and 233% in the peel and pulp, respectively. During the berry development process of ‘Nantaihutezao’, the contents of characteristic aroma compounds accumulated in peel first increased rapidly and then decreased slowly, and the peak values were higher and appeared earlier than those of ‘Summer Black’. There were significant differences in the contents of 1-octen-3-one, β-damascenone and limonene in the pulp of the two grape cultivars. The contents of ‘Summer Black’ maintained at a high level in the middle of maturity and rapidly degraded in the later period; by contrast, the contents of ‘Nantaihutezao’ increased slowly in the middle and less degraded in the later period. The above results provide a theoretical basis for the aroma genetic breeding of excellent and new grape cultivars.
Sixty-eight simple sequence repeat (SSR) primer pairs were designed based on the transcriptome data of Cymbidium faberi and 25 primer pairs with stable amplification and better polymorphism were selected for genetic diversity analysis of 41 C. hybridum cultivars. The results showed that a total of 187 SSR bands were amplified, and 171 (91.44%) of them were polymorphic with the average of 6.84 bands per primer pair. The mean value of polymorphism information content (PIC) and the number of genotypes per SSR marker were 0.770 3 and 12.88, respectively. Genetic similarity coefficient among 41 cultivars ranged from 0.57 to 0.99 with an average of 0.72. A dendrogram of genetic relationship constructed using unweighted pair-group method with arithmetic mean (UPGMA) showed that the tested accessions could be classified into five clustering groups with the similarity coefficient of 0.71, which were consistent to some extent with the plant size, branch type and flower color. The above results reveal the genetic diversity and relationships among the tested accessions. The newly developed SSR markers will be useful tools for molecular breeding of C.hybridum.
The effects of spraying selenium (Se) at different stages on Se contents and fruit quality of citrus were studied to provide basic data for rational Se application. A foliar spray of 200 mg/L sodium selenite solution was applied to 15 years’ ‘Bendizao’ mandarin (Citrus succosa Hort. Ex Tanaka) at the young fruit stage, fruit expansion stage and fruit coloring stage, respectively. Leaf and fruit samples were collected at the maturing stage to detect Se contents, organic degree of Se, other nutrient contents and fruit quality. The result showed that spraying Se before the fruit coloring stage increased total Se contents in the leaves and fruits. Se organic proportion of fruit decreased with the delay of Se spraying date. The activities of superoxide dismutase and peroxidase under the spraying Se treatments were higher, but the content of malondialdehyde was lower. Se promoted the absorption of total nitrogen and total potassium, but inhibited the absorption of total phosphorus, total calcium and total magnesium. The fruit peel was thinner, the content of total acid was lower, and the contents of soluble solid, total sugar and vitamin C were higher by spraying Se at the young fruit stage. In conclusion, foliar spraying Se can improve the fruit quality by increasing the Se contents and affecting the balance of nutrient absorption, thus improving the antioxidant capacity and the quality of citrus fruits. The comprehensive effect of foliar spraying Se at the fruit young stage is the best.
In this study, we explored the effects of exogenous melatonin (MEL) and epibrassinolide (EBL) on the regeneration of callus subcultured for 17 years of Zoysia matrella (L.) Merr. under simulated drought stress, aiming to select the optimal MEL or EBL concentrations that improved the regeneration capacity of callus, and obtain plants with strong drought resistance. The results showed that 0.20 mmol/L MEL markedly promoted the regeneration of callus, and the regeneration rate was 61.1%. Different degrees of drought stress significantly affected the regeneration capacity of callus, and the regeneration rate decreased as polyethylene glycol (PEG) concentration increased. Under 5% and 10% PEG-6000 stress, the regeneration plants of Z. matrella with strong drought tolerance could be obtained. Under 5%-15% PEG-6000 stress, addition of 0.05-0.20 mmol/L MEL or 0.05-0.50 μmol/L EBL promoted the recovery of callus regeneration. Under 10% PEG-6000 stress, 0.20 mmol/L MEL was the best treatment to promote the callus regeneration, and the regeneration rate was as high as 55.6%. High concentrations of MEL and EBL inhibited callus regeneration rates. Moreover, when adding 0.05-0.20 mmol/L MEL under 5% or 10% PEG stress, catalase activity of callus increased markedly; when adding 0.05-0.10 μmol/L EBL, peroxidase, superoxide dismutase activities of callus significantly increased, and the two exogenous hormones evoked response of different antioxidant enzymes during the regeneration of Z. matrella callus. It can be seen that, 0.05-0.20 mmol/L MEL or 0.05-0.10 μmol/L EBL notably promote the regeneration capacity of Z. matrella callus. This study provides new pathways for improving the regeneration capacity of callus in long-term subculture and drought-resistant selection of Z. matrella.
