29 September 2013, Volume 27 Issue 9
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J4. 2013, 27(9): 1241-1246. https://doi.org/10.11869/hnxb.2013.09.1241To innovate soybean varieties and explore breeding techniques, the sexual F2 generation of space mutation was used in this study, pedigree breeding method was applied to develop a new soybean variety "Keshan No.1". The oil content of the variety was 21.82%, the protein content was 38.04%, the average yield was 2629.5 kg·hm-2 in early group of the national region testing during 2007-2008, the yield of Keshan No.1 was 11.4%;higher than that of the control (HeiheNo.18), the average yield was 2643.8 kg·hm-2 in production testing, the yield of Keshan No.1 was 6.9% higher than that of the control (HeiheNo.43), it ranked the first place. Using shukla stability variance analysis, the yield of Keshan No.1 was stable, Keshan No.1 was approved by the National Crop Examination Committee (National examination:2009002) in 2009, the prominent characteristics of this variety are early-maturity, good-quality, high -yield, good yield-stability and wide-adaptability, Keshan No.1 is suitable for planting in the northern part of Heilongjiang Province, the eastern mountain areas of Jilin Province, the northern part of Xinjiang and the central areas and southern areas of Inner Mongolia Hulunbeier in spring season.
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J4. 2013, 27(9): 1247-1252. https://doi.org/10.11869/hnxb.2013.09.1247Inter-Simple Sequence Repeat(ISSR) molecular markers were used to analyze the Cymbidium ‘longchangsu’ seedlings in vitro, mutagenic progenies and the leaf shape mutants by 60Co γ rays. Results showed that the differentiation rate of the radiated rhizomes by 10Gy and 20Gy were 93.2% and 54.4%,respectively. The rhizomes radiated by 40Gy and 60Gy were all died. The mutation rates of seedlings by repeatedly subcultured in vitro were 6% and the mutagenic progenies by radiation were 18%.It is indicated that the mutagenic rates caused by radiation is higher than that by tissue culture. No significant differences were observed between suspicious mutants and the control after the gene detection of the leaf shape mutants. It suggests that,maybe,there were not significant correlation between ISSR results and the morphological changes.
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J4. 2013, 27(9): 1253-1257. https://doi.org/10.11869/hnxb.2013.09.1253The initiation, maintenance and differentiation of callus from seedling-derived leaves of maize (Zea mays L.) inbreds were studied and optimized. The results revealed that medium CIM1 was the best medium in the experiment. Callus obtained could achieve higher differentiation rates after modified treatment. All showed that, selecting appropriate induction medium and appropriately modified callus could improve callus regeneration rate,which benifits to the establishment of an efficient tissue-culture regeneration system for maize.
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J4. 2013, 27(9): 1258-1269. https://doi.org/10.11869/hnxb.2013.09.1258The transcription factors play important roles in plant stress tolerance. treating with different PEG concentrations to simulate different intensities of drought stress, the expression change of transcription factor families and transcription factors in rice roots with different drought-tolerance were studied by microarray analysis. The results showed that a total of 296 transcription factors in 43 transcription factors families changed under at least one drought stress treatment. There were 36 overlapping transcription factors in 24 transcription factor families expressed among 3 different intensities of drought stress. Under drought stress, the expression of transcription factor showed strong specificity among different drought-tolerance rice varieties. Among drought resistant varieties and susceptible varieties, 26 transcription factors in 18 transcription factor families showed expression changes under 3 intensities of drought-stress treatment, in which14 transcripts were down-regulated and 12 transcripts were up-regulated.
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J4. 2013, 27(9): 1270-1275. https://doi.org/10.11869/hnxb.2013.09.1270Genetic diversity and genetic relationship of 45 varieties of table grape (Vitis L.) were analyzed by Inter-Simple Sequence Repeat (ISSR) markers in southern China. Twenty-six highly efficient amplification primers were selected from 100 arbitrary primers., 283 of the total 310 bands amplified showed polymorphisms, and the mean ratio of polymorphism was 91%. The genetic similarity coefficient among the 45 samples floated from 0.603 to 0.908. The clustering dendrogram was constructed by UPGMA method. At the point of 0.703, all the samples were classified into two groups: V. vinifera L. and hybrid of V. vinifera L.×V. labrusca L.. The varietal typesof Meifeng and Meiqiu were unknown. According to the clustering analysis, the similarity coefficient between Meifeng, Meiqiu and Yuxuan 4 was 0.902 and 0.898 respectively, which suggested that the two varieties belong to pedigree of Kyoho grapevine series, hybrids of V. vinifera L.×V. labrusca L. Golden Queen might belong to V. vinifera L., and a further study of its parental origin is needed.
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J4. 2013, 27(9): 1276-1284. https://doi.org/10.11869/hnxb.2013.09.1276ε-COP is one of the subunits of Coat protein I-coated vesicles (COPI) in eukaryotic cells. The biological function of ε-COP in plants remains unclear. In this study, bioinformatic analysis of genes encoding ε-COP in rice was performed. Afterwards, the expression pattern of Osε-cop1 was studied and the RNA interference (RNAi) plasmid was constructed, followed by Agrobacterium-mediated transfection into rice callis. The expression of Osε-cop1 and the phenotype changes in transgenic generations were tested. Bioinformatic analysis revealed that two genes encoding Osε-cop in rice showed high sequence consistency. The consistency of Osε-COP protein sequence with ε-COP in Maize, Arabidopsis and Soybean was 83%, 68% and 62%, respectively. The analysis of expression pattern showed that Osε-cop1 was specifically expressed in panicles with the most abundant at meiosis stage. Study of RNAi demonstrated that the decrease of Osε-cop1 resulted in death of spikelets in the top of panicles, implying that this gene was important for the development of rice panicles. This work reveals the essential function of Osε-cop1 gene in rice, which would greatly promote the research of biological function of COPI in plants.
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J4. 2013, 27(9): 1285-1292. https://doi.org/10.11869/hnxb.2013.09.1285Seven boll traits and five fiber quality traits of nine parents and their 36 F1 crosses of upland cotton (Gossypium hirsutum L.) for two years and their genetic covariance components between pair-wise characters were analyzed by additive-dominance genetic model with genotype by environment interaction effects. Additive and dominance covariances between fiber length and boll length were positive and significant. Fiber uniformity was significantly and positively correlated with boll length and width in dominance effects. Micromaire showed significant and negative genetic correlation with boll width but positive with ratio of boll length to boll width in additive effects. Elongation was significantly and positively related with ratio of boll length to boll width in additive effects, as were fiber strength and boll width and boll length. Positive additive covariance is a main component of genetic covariance between three boll morphological traits and fiber traits, except uniformity, suggesting indirect selecting of boll morphological traits helpful to the improvement of cotton fiber in early generation of hybrid. Fiber length exhibited positive dominance correlations with boll weight, fiber mass per boll, seed mass per boll and single boll seeds at 0.01 level, but negative additive correlation with single boll seeds at 0.05 level. Significant and positive dominance correlations were found between fiber elongation and fiber mass per boll and single boll seeds, as were fiber strength and seed mass per boll. Positive genotypic correlations between fiber traits and four within-boll yield components are due to dominance genetic covariance, indicating those traits can be improved simultaneously by heterosis utilization.
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J4. 2013, 27(9): 1293-1301. https://doi.org/10.11869/hnxb.2013.09.1293Lily virus disease is one of the most seriously damaged disease. Due to the narrow genetic basis of lily breeding materials, lily resistance breeding for new antiviral varieties was always at a standstill. In this study, Lily symptomless virus (LSV)、Lily mottle virus (LMoV) and Cucumber mosaic virus(CMV),three widely distributed and seriously damaged virus' coat protein genes were cloned. To provide new planting germplasm resources and resistance breeding materials for lily, three coat protein genes plant expression vector was constructed, and transformed into callus of Lilium by Agrobacterium tumefaciens-mediated.
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J4. 2013, 27(9): 1302-1307. https://doi.org/10.11869/hnxb.2013.09.1302The changes of total bacterial count, the content of water, fat, protein, fatty acid and amino acid of steamed tofu rolls treated with electron beam (EB) irradiation were investigated. The appropriate dose of EB irradiation on steamed tofu roll was proposed for industry application. The results showed that EB irradiation ≥4.5kGy could extend the shelf-life of steamed tofu roll to 30 days when its bacterial load was no more than 105 CFU·g-1. There were no significant differences (P>0.05) in sensory characteristic, the content of fat, fatty acids, amino acids and protein between samples treated with 6.5kGy and the control. Therefore, the optimum dose range for steamed tofu roll with bacterial load no more than 105 CFU·g-1was 4.5 to 6.5kGy, which could extend its shelf life to 30 days.
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J4. 2013, 27(9): 1308-1316. https://doi.org/10.11869/hnxb.2013.09.1308In oder to explore safe, simple and effective storage technology, experiment was conducted with "ai li ao te"blueberry for studying the effect of electron beam on quality and physiological metabolism. Fruit was stored at temperature of(1±0.5)℃, with RH of 80%~85%, and treated with electron beam of 0.5、1、1.5、2、3kGy. The results showed that the proper dose of electron beam could decline the bad fruit rate and weightlessness, restrain respiration intensity, alleviate the decline of soluble solids, acid and Vc content. Meanwhile it did not have significant negative effects on pulp colour. All these showed that electron beam of 1kGy treatment could keep the best storage quality of blueberry, keep the sound berry and weightlessness rate at >90% and <10% respectively, prolong the effective storage time from 30d to 60d.
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J4. 2013, 27(9): 1317-1323. https://doi.org/10.11869/hnxb.2013.09.1317The pretreatment technology of explosion puffing drying peach was investigated in the present study. The optimal pre-drying temperature of explosion puffing drying was chosen, and effects of three different color retention agents including calcium chloride, citric acid, ascorbic acid and the influences of different impregnation liquid including high fructose corn syrup, maltitol, malt syrup and milk on the color and texture of explosion puffing drying peach were evaluated. The results showed that the optimal temperature of pre-drying was 80℃, under which the material was dried fast and the color was better; 2.5% of citric acid penetration fluid obviously maintained the material color; qualities of the products such as color, hardness and crispness was significantly enhanced by 25% of sugar syrup impregnation.
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J4. 2013, 27(9): 1324-1330. https://doi.org/10.11869/hnxb.2013.09.1324Dietary fiber is called "the seventh major nutrient" for human, which plays a very important role in keeping human health. The research progress in prevention and treatment of diabesity and the complications thereof is summarized in this review from three aspects, including epidemiology, animal experiments and clinical trials, and the mechanism thereof is also discussed.
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J4. 2013, 27(9): 1331-1336. https://doi.org/10.11869/hnxb.2013.09.1331The contents of mineral elements and amino acids of a group of new giant embryo rice (ge-rice) strains that were bred by the Institute of Crop Genetics and Breeding, Fujian Agriculture and Forestry University were measured. The results indicated that: the average content of five mineral elements, K, Zn, Cu, Mn and Fe of new ge-rice strains increased by 50.65%, 12.65%, 28.58%, 100.12% and 112.86% compared with the control, M86. However, the highest content of Se was 0.17mg·kg-1 in the gewx1 that was 8.5-folds that of M86 (0.02mg·kg-1). The majority of amino acids in ge-rice were higher than that of CK. The average essential amino acids (EAA) and total amino acids (TAA) of ge-rice reached 3.424% and 8.934%, which increased by 29.05% and 31.00% respectively. The average content of γ-amino butyric acid (GABA) of ge-rice strains was 5.81mg·100g-1, which was 3.2-folds of M86. The average content of peptide of ge-rice was 20.98mg·g-1 and increased by 53.73% compared with M86(1.81mg·100g-1). Correlation analysis suggested that there were significant positive correlation among the relative embryo weight and the levels of most of the nutrients. This indicated that the content of these nutrients could be improved by the relative embryo weight in rice.
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A Review in the Potential Influence of Cell Death way and the Activation of Caspases on Meat QualityJ4. 2013, 27(9): 1337-1341. https://doi.org/10.11869/hnxb.2013.09.1337In recent five years, apoptosis and caspases were focused by Meat Scienceentist. The degradation of cytoskeletal proteins mediated by caspases was well known. However, the process of activation and factors which influenced the process were still not very clear. In this work, the postmortem changes of cellular environment which effects the activation of caspases is analyzed; the studies focused on apoptosis and caspases in Meat Scienceence were reviewed; the mark proteins identified in medicine science was listed; the opinion on the mechanism of meat conditioning was suggested finally.
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J4. 2013, 27(9): 1342-1347. https://doi.org/10.11869/hnxb.2013.09.1342The preservation effect of slurry ice on Pampus argenteus was studied by comparison with traditional flake ice treatment in this paper. The results showed that both slurry ice and flake ice could inhibit the growth of microorganism, delay the increase in pH, TVB-N and K values, slowdown the decrease in texture characteristics and sensory quality. Moreover, the fresh-keeping effect of slurry ice was better than that of flake ice. The total number of bacteria, coliform group, pH, TVB-N and K values were lower than that in flake ice. According to the aquatic industry standard, using the TVB-N value as an evaluation index, the TVB-N value for samples treated with slurry ice was 31.3 mg·100g-1 after 17 days of storage, so the shelf-life time was 17d. When the Pampus argenteus was stored with flake ice, the TVB-N value was 32.2 mg·100g-1after 15 days of storage, so the shelf-life time was 15d. The results suggested that slurry ice prolonged shelf life and improved the quality for preservation of Pampus argenteus compared to the flake ice. Slurry ice is advantageous to the preservation of the fresh Pampus argenteus.
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J4. 2013, 27(9): 1348-1353. https://doi.org/10.11869/hnxb.2013.09.1348The effects of different sowing date on tuber growth and main medical components of Corydalis decumbens were studied to provide the theoretical basis for its cultivation technology. The results showed that both its germination and new tuber formation was delayed correspondingly with the sowing date postponed, however, the withered date of overground parts was less affected by the sowing date; The C. decumbens was able to bloom under the earlier sowing condition but not when it was later sowed. In late March, the tuber had grown rapidly in all sowing dates, nevertherless, the tuber growth declined on the two sowing date of October 23 and November 4. The growthof the tubers sowed on November 14 and November 25 had risen since April 5. The tuber had rapid growth before bloom, but declined after blooming, in addition, it could increase the tuber yield of Corydalis decumbents with the treatment of defloration in the flowering period. The effects on main medical protopine and tetrahydropalmatine component of C. decumbens were insignificantly under different sowing dates. The suitable sowing date of C. decumbens was in late October to early November.
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J4. 2013, 27(9): 1354-1359. https://doi.org/10.11869/hnxb.2013.09.135441 tobacco leaves samples from Xiangxi areas were analyzed by sensory evaluation in order to ascertain the regional characteristics and spatial distribution of smoke characteristics. The results were as follows: (1) The smoke of flue-cured from Xiangxi was a little smoothy, a little softness and a little mellow. (2) There were extremely significant differences among the different counties for the smoke mellow, non-significant differences among the different counties for the smoothy and softness; the smoke mellow of flue-cured tobacco from Guzhang County was relatively higher than others. (3)The scale of smoothy and softness of flue-cured tobacco from Liexi town were the highest among the different towns, while the scale of mellow from Hongshilin town was the highest. (4)The smoke quality of ‘K326’ was better than ‘Yunyan87’. (5) The smoke quality of flue-cured tobacco from plant-tobacco areas under 600m altitude was better than others. (6) The Kriging interpolation map indicated that the spatial distributions of the scale of smoke characteristic indexes were plaque. The 2.8 to 2.9, 2.6 to 2.8 and 2.5 to 2.6 were main distribution of smoothy, softness and mellow, respectively.
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J4. 2013, 27(9): 1360-1365. https://doi.org/10.11869/hnxb.2013.09.1360Soybean was used as soil conditioner with different treatments, and the influence of different treatments on soil basic properties, corn biomass, and the effects of bioconcentration and migration on 238U, 226Ra, 232Th and 40K were analyzed. Pot experiment results showed that adding soybean dregs could significantly decrease the pH value of soil. The changes of soil pH value, organic matter content and cation exchange capacity with the corn biomass had significant influences on the bioavailability, bioconcentration factor (BCF) and transfer factor (TF) of 40K, but had insignificant influences on 238U, 226Ra and 232Th. Except for 238U, there was extremely significant linear correlation between the BCF and TF to the aboveground parts of corn for the other three nuclides.
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J4. 2013, 27(9): 1366-1370. https://doi.org/10.11869/hnxb.2013.09.1366The degradability of polyethylene films were performed under absorbed doses of 0, 10, 50, 100kGy by 60Co γ ray. The radiated polyethylene films were investigated by FT-IR spectrum, water contact angle, SEM images and tensile strength. The results showed that the radiated polyethylene films exhibit more hydrophilic and less mechanical properties. When 60Co γ-ray irradiation dose reached 100 kGy, large of crack was observed in the polyethylene films surface and the water contact angle rose up to 44°, which was available for microbe adsorption. Thus, the method of 60Co γ-ray irradiation is an effective way for degradation of polyethylene films.
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J4. 2013, 27(9): 1371-1377. https://doi.org/10.11869/hnxb.2013.09.1371Based on comprehensive investigation of Armeniaca sibirica 3 main production areas, sample plots were set and samples were collected. The types were divided based on variation of Armeniaca sibirica almond main phenotype and economy characteristic determination, and then economy characteristic of each type was analyzed and evaluated. The results were as follows: (1)The within a tree variation of Armeniaca sibirica almond quantity characteristic was smaller, but the individual trees were bigger, providing the basis for superior type selection.(2) The small ovate kernel type belongs to the superior type of Armeniaca sibirica in the north Changbai Mountain. The big cordiform kernel type and middle elliptic kernel type were the superior types of Armeniaca sibirica in the south foot of Daxinganling Mountain. The middle cordiform kernel type and big cordiform kernel types were the superior types of Armeniaca sibirica in the south foot of Yan Mountain and the north Taihang Mountain. As there was no clone breed that could use, these 5 superior types of each areas could try to promote through clonal means.
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J4. 2013, 27(9): 1378-1384. https://doi.org/10.11869/hnxb.2013.09.1378Under long-term experiment in dryland of Loess Plateau, effects of five kinds of fertilization on the nutritional quality of wheat protein were studied in this paper. The treats included nitrogen fertilizer (N), phosphorus fertilizer (P), organic fertilizer (M), nitrogen fertilizer mixed phosphorus fertilizer (NP), organic fertilizer mixed nitrogen fertilizer and phosphorus fertilizer (NPM).The results showed that the protein contents and the total amino acid contents in wheat grain significantly increased by 45.2%~52.3% and 51.6%~80.1%, respectively, after applied with NP, NPM and M, and their essential amino acids/total amino acids and essential amino acids/non-essential amino acids were closer to the WHO/FAO standard. Fertilization obviously improved leucine contents of wheat grain protein with an increase of 71.4%~114.3%, increased sulfur-containing amino acids contents with 6.3%~81.3%, and further raised their essential amino acid scores and chemical scores. However, lysine contents were equal or lower than control after fertilization, which made lysine the first bottleneck amino acid. Fertilization could accelerate the balance of amino acid and grain protein, and the order of the essential amino acid index was NP > M > NPM > N > P > CK. Application of NP and M could improve the nutritional quality of wheat grain protein in Loess Plateau.
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J4. 2013, 27(9): 1385-1390. https://doi.org/10.11869/hnxb.2013.09.1385A field experiment was conducted to study effects of controlled-release coated urea of 60-d release duration (CU60) combined with conventional urea (U) on dry matter and N accumulation amount at silking stage, nitrogen use efficiency, aboveground biomass nitrogen accumulation amount, yield, economic benefits for spring maize. In addition, nitrogen release was carried out under field conditions. The results indicated that when the same dosage nitrogen was applied, the ratios of dry matter and N accumulation amount after silking stage were higher than those of CK2. After comparasion of CU60 combined with U treatment and the traditional treatment (CK2), the accumulations of total nitrogen and maize kernel nitrogen were obviously higher than CK2 with apparent recovery efficiency of applied N up by 2 to 12%, agronomic efficiency of applied N up by 2 to 5%, partial factor productivity from applied N up by 2 to 6 per cent. The best ratio is 30%CU: 70%U was when compared with other treatments. The spring maize yields were increased under 25%CU60+75%U, 30%CU60+70%U, and 40%CU60+60%U used as base fertilizer with the grain yield increased by 7.3%~10.7% and net economic benefit increased by 1425~2166 yuan·hm-2. Compared with other treatments, the treatment of 30%CU+ 70%U has the highest1000-grain weight and grain yield. Nitrogen release under field conditions of controlled-release coated urea of 60-d release duration was longer than under static water conditions at 25℃, the nutrient release under field conditions was accorded with nitrogen absorption dynamics of spring maize in Dongbei sandy loam region. To sum up, 30% CU60 combined with 70%U was a optimal choice for Dongbei spring maize production, especially for sandy loam.
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J4. 2013, 27(9): 1391-1400. https://doi.org/10.11869/hnxb.2013.09.1391In order to systemically and deeply study the effects of different nitrogen (N) levels on the plant growth and leaf photosynthesis characteristics, especially the light reaction of sugar beet (Beta vulgaris L.) seedlings, ‘Shuangfeng 16’ (higher yield diploid varieties) and ‘Tianyan 7’ (higher sugar content diploid varieties), two cultivars seedlings were used in pot culture experiment with five N application levels. Morphological and biomass indexes, some biochemical parameters and photosynthetic characteristics such as leaf gas exchange, leaf photosynthetic pigment content, RuBP carboxylase activities and chlorophyll fluorescence parameters of sugar beet seedlings were determined. The results showed that with N supply increasing, the leaf area, biomass of different components, content of leaf N and soluble protein, RuBP carboxylase activities and gas exchange parameters increased at first and subsequently decreased. The promoting effect of N application on the above-ground biomass accumulation was much stronger than that on the under-ground one. N supply significantly decreased the root/shoot ratio and specific leaf mass (P<0.05). In addition, leaf photosynthetic pigment content, leaf maximum quantum yield of PSII photochemistry (Fv/Fm), light energy capture efficiency in primary reaction of PSII (F'v/F'm) and actual photochemistry efficiency of PSII (Y(II)) increased with N application, while the regulated non-photochemical quenching values (Y(NPQ)) exhibited a converse tendency. At the same time, regulated non-photochemical quenching (NPQ) and fast-relaxing NPQ (NPQF) were significantly affected by N-supply (P<0.05). Under the experimental conditions, proper N supply (60 to 180kg·hm-2) may promote the photosynthetic characteristics, growth, and better yield and quality of sugar beet by improving photochemical activity, such as increasing photosynthetic pigment concentration, PSII potential activity and the maximal quantum efficiency of PSII, as well as reducing non-photochemical quenching coefficient, avoiding the photoinhibition, and enhancing stomatal conductance and carboxylation efficiency in sugar beet leaves. But when the nitrogen application level was too high, its promotion in leaf photosynthesis and plant growth of sugar beet seedlings was weakening.
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J4. 2013, 27(9): 1401-1408. https://doi.org/10.11869/hnxb.2013.09.1401Effects of different drip irrigation water levels during productive growth stage on fruit development, irrigation water use effect, fruit production, quality and sensory experiences for muskmelon (Love net) were studied in a plastic greenhouse. The irrigation was determined by Time Domain Reflectometry (TDR), and there were five different irrigation water levels relative to the percentage of field water capacity, 85%-T85, 75%-T75, 65%-T65, 55%-T55, 45%-T45, respectively. The results showed that the fruit vertical diameter growth was ahead of transverse diameter, and T65 was faster than others on the fruit early development with T85 and T65 bigger than others on late development. Fruit shape index decreased with the reduced irrigation water, but with little difference. The irrigation water use efficiency (IWUE) of T65 and T55 were significantly increased, by 14.1kg·m-3and 14.0kg·m-3, respectively. T65 increased by 16.2% more than T85, saving water amount about 15.8%. The yield and single fruit weight was the best for T85. The contented of TSS(Total soluble solid, TSS)was ranked as T65>T55>T85>T75>T45, and the content for T65 was up to 10.67%, and 18.95% higher than that of T85. The limbic sugar content of T65 and T55 were better than others, butno significant difference was found. Center sugar content of T65 was the best, and that of T45 was the lowest. Soluble sugar content of T65 and T75 were better, and the difference was not significant. As to T85, fruit soluble protein and Vc content were the better, but lower for center sugar and limbic sugar. Moreover, aroma, firmness and juiciness were the best for T65, sweetness, taste and global acceptance at organoleptic examination were the best for T75. Therefore, based on indexes of yield, IWUE, quality and organoleptic examination, 65% of field capacity would be the best for the reproduction growth of melon inside plastic greenhouse.
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J4. 2013, 27(9): 1409-1415. https://doi.org/10.11869/hnxb.2013.09.1409In order to study the effect of plant growth regulators on Lycoris bulblets development, the carbohydrate contents and relevant enzyme activities were assayed after spraying CPPU, chlorocholine chloride (CC) and salicylic acid (SA) with low and high concentrations, respectively, on leaves at the green period. The results showed that the three plant growth regulators could effectively stimulate growth and development of the bulblets. The most effective treatment was achieved after application of 5mg/L CPPU, and the carbohydrate contents and enzyme activities increased accordingly. It was indicated that the CPPU enlarged the bulblets by promoting bulb nutrient metabolism and accelerating the accumulation of starch. However, the CC and SA probably expanded the bulblets size in other physiological ways besides nutrients metabolism. At the same time, β-amylase was considered to play an important role in the starch metabolism of the bulblets.
