Two compounds with strongly insecticidal and fungicidal activity, Kurarinone and Sophoraflavanone G , were isolated from Sophora flavescens Ait under the direction of bioassay, and comfirmed by UV, IR, MS and NMR. The...Two compounds with strongly insecticidal and fungicidal activity, Kurarinone and Sophoraflavanone G , were isolated from Sophora flavescens Ait under the direction of bioassay, and comfirmed by UV, IR, MS and NMR. The insecticidal activity of flavonoids from Sophora flavescens Ait was first reported here. The study of structure-activity relationship indicated that the methylation of 5-hydroxy on the phenyl ring would decrease the insecticidal and fungicidal activity of flavonoids.展开更多
The dissipation of chlorpyrifos on pakchoi inside and outside greenhouse was studied. The decline curve of chlorpyrifos on pakchoi could be described as first-order kinetic. The experimental data showed that both the ...The dissipation of chlorpyrifos on pakchoi inside and outside greenhouse was studied. The decline curve of chlorpyrifos on pakchoi could be described as first-order kinetic. The experimental data showed that both the hermetic environment of greenhouse and season affected dissipation rates of chlorpyrifos on pakchoi. Chlorpyrifos declined faster outside greenhouse than inside greenhouse. Chlorpyrifos residues at pre-harvest time were below the maximum residue limits(MRLs) fixed in China, whereas the values inside greenhouse were higher than those outside greenhouse by almost 50%. The recommended pre-harvest time established under conditions of open field might not always fit to greenhouse production.展开更多
The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showe...The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showed that the chlorophyll content,maximal photochemical efficiency of PSⅡ(Fv/Fm), Fm/Fo, amount of inactive PSⅡreactioncenters (Fi-Fo) and rate of QA reduction were positively correlated with the red-light/blue-light ratios, but the chlorophyll (a/b) ratios were negatively correlated withthem. Carotenoid content of the leaves was maximum under the blue film, than under greenfilm, red film, white film and yellow film, and negatively correlated with the red/far-red ratios. The apparent quantum yield (AQY), photorespiratory rate (Pr) and carboxylationefficiency (CE) were also strongly affected by light quality. The photosynthetic rate(Pn) in strawberry leaves under green film was significantly lower than under all otherfilm. Our results suggested that light quality is an essential factor regulating thedevelopment of PSⅡ, and phytochrome and an independent blue light photoreceptor,possibly a cryptochrome, can regulate photosynthetic performance.展开更多
Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precult...Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4-7 days and then co cultivated with Agrobacterium tumefaciens , LBA4404, which contains plasmid vector pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4 D, 12-15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2-3 months of selection, the actively growing calli of 'Regent' and 'Tiger' were transferred to MS medium with 12-15 mg/L PPT and 250 mg/L cefotaxime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.展开更多
A 855 bp cDNA encoding L-galactono-1,4-lactone dehydrogenase (GalLDH) fragment was cloned from fruit of R. roxburghii Tratt by the method of RT-PCR, on the basis of the homologous genes of Arabidopsis thaliana, caul...A 855 bp cDNA encoding L-galactono-1,4-lactone dehydrogenase (GalLDH) fragment was cloned from fruit of R. roxburghii Tratt by the method of RT-PCR, on the basis of the homologous genes of Arabidopsis thaliana, cauliflower, sweet potato, strawberry, etc. in GenBank. Sequence analysis showed 79-92% identity in nucleotide sequence and 75-87% identity in amino acid sequence to that of strawberry and Arabidopsis thaliana, etc. Northern blot showed that the expression of GalLDH was significantly different in different organs. The transcription level of GalLDH in fruit was significantly higher than that in leaf, stem and root respectively. Furthermore, this expression mode was highly correlated with AsA levels.展开更多
α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein...α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein, zeaxanthin and β-cryptoxanthin. β-carotene content was relatively low and extremely low was the amount of α-carotene. Among the 53 cultivars tested, lycopene was detected only in pulp of Cara Cara navel orange. Carotenoid content in both peel and pulp of citrus fruit was the highest in Citrus reticulata Blanco and lowest in Citrus grandis Osbeck. Consequently, as far as the health protection value is considered, fruit of Citrus reticulata Blanco ranks probably higher than other citrus fruits. In fruit of most Citrus reticulata varities, β-cryptoxanthin was the main carotenoid component in pulp and its amount approximated that of lutein in peel. Content of lutein, zeaxanthin and β-cryptoxanthin in peel was about 2.515 times that in pulp on the basis of fresh weight. Thus peel was inferred to be the principal location for the carotenoid stock in citrus fruit.展开更多
Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resi...Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resistance. The results showed that under 40C(day/night), Ca2+ immersion pretreatment enabled the eggplant seedlings to keep relatively higheractivities of superoxide dismutase(SOD) and peroxidase(POD), reduced the production rate ofsuperoxide anion O2_ and the content of malondialdehyde(MDA), alleviated the damage of reducedglutathione(GSH) and the accumulation of proline (Pro), whereas calmodulin antagonist TFP andW7 immersion pretreatments could lead to more rapid loss of SOD and POD activities, increasethe contents of MDA, Pro and production rate of O2_, aggravate the damage of GSH. Under the samestress condition, heat-resistant variety Nongyouqie was less injured compared to the heat-sensitive variety Erminqie. These data indicated that Ca2+-CaM signal transduction systemmight regulate the heat resistance of eggplant seedlings by controlling the activity of someantioxidant enzymes and the contents of antioxidant substance.展开更多
The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (\%Red Fuji/Malus micromalus Makino\%) duri...The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (\%Red Fuji/Malus micromalus Makino\%) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46±0.35 nmol g\+\{ 1\}FW and 117 nmol l\+\{-1\} after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day , it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment. Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.展开更多
Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this spec...Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this species and its first selfed progeny would increase its potential utility in cucumber improvement. With tendrils used as source materials for mitotic analysis, chromosome numbers in all selfed progenies were 2n = 38, confirming chromosomal stability in this synthetic amphidiploid species. Detailed meiotic processes were described by comparing the primary and the selfed amphidiploids. Meiotic abnormalities, such as chromosome lagging, unequal separation, chromosome multi-polarization and polyads were observed frequently in all amphidiploid plants except for the selfed no.8, in which meiosis was arrested prior to metaphase Ⅰ. Generally, the frequency of multivalents was higher and the configurations were more complex in the selfed progenies, demonstrating a more extensive genetic exchange between cucumber and C. hystrix Chakr. Genome separation between cucumber and C. hystrix was observed through prophase Ⅰ to anaphase Ⅰ in both generations of the amphidiploids. Consequently, in addition to n = 19, a new gamete with n = 7 was produced, which was confirmed by the chromosome counts 2n = 14 in the backcrossing progenies from cucumber × amphidiploid mating. Fertility varied among the selfed amphidiploid plants. The selfed plant no.1 was found to have an improved fertility (e.g., pollen staining ability 40.8% and 25.6 seeds per fruit) and then was used as source germplasm in further introgression and gene exchange experiments.展开更多
The dynamics of translocation and partitioning of 14C-phothsynthates, the concentration of sucrose in fruit tissues and the effects of the membrane carrier- and ATPase-specific inhibitors on 14C-sucrose uptake by juic...The dynamics of translocation and partitioning of 14C-phothsynthates, the concentration of sucrose in fruit tissues and the effects of the membrane carrier- and ATPase-specific inhibitors on 14C-sucrose uptake by juice sacs of the satsuma mandarin(Citrus unshiu Marc. cv. Miyagawa wase)fruit were examined at the stage of fruit enlargement and fruit full ripe. Kinetic data of 14C-photosynthate translocation indicated that the rate of photosynthate transport into juice sacs decreased with fruit maturation and sugar accumulation. Along the photosynthate translocation path, i. e. from vascular bundles to segment epidermis then to juice sacs, a descending sugar gradient was observed. With fruit maturation and sugar accumulation in juice sacs, the 14C photosynthate gradient increased, whereas the static sucrose concentration gradient decreased with fruit maturation and sugar accumulation. The higher gradient of specific 14C radioactivity was considered to favor diffusion and sugar transport into juice sacs at the later stage of fruit development. The rate of uptake 14C-sucrose by juice sacs of satsuma mandarin fruit was markedly reduced by PCMBS, EB, DNP and NO3-treatment. The above results suggested the participation of a carrier-mediated, energy-dependent sugar active transport process in juice sacs of satsuma mandarin fruit.展开更多
The influences of different rootstocks on chilling tolerance and physiological parameters in watermelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Compared with own...The influences of different rootstocks on chilling tolerance and physiological parameters in watermelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Compared with own-rooted watermelon seedlings, the grafted watermelon seedlings had lower chilling injury index, lower electrolytic leakage (%), lower malondialdehyde (MDA) content, higher chlorophyll and proline content, and higher activities of superoxide dismutase (SOD), ascorbate peroxidase (AsA-POD) and dehydroascorbate reductase (DR) in the leaves under low temperature stress. There was a considerable difference of chilling tolerance among different grafted watermelon seedlings due to the difference of rootstock chilling tolerance. After low temperature treatment, the grafted seedling with higher chilling tolerance had lower electrolytic leakage (%),lower MDA content, higher proline content and higher activities of SOD, AsA-POD and DR in the leaves compared with the grafted seedling with weaker chilling tolerance. From these, we could conclude that chilling tolerance of watermelon seedlings may be related to higher antioxidative ability and membrane stability in the plants. The chilling tolerance of grafted seedling could be properly evaluated by comprehensive physiological indexes but not a single physiological index.展开更多
Greenhouse grown 1 year old potted M.9EMLA apple trees ( Malus pumila Borkh) were subjected to the soil compaction and, after growing under compacted or non compacted conditions for 6 weeks, were subjected to ...Greenhouse grown 1 year old potted M.9EMLA apple trees ( Malus pumila Borkh) were subjected to the soil compaction and, after growing under compacted or non compacted conditions for 6 weeks, were subjected to drought stress by withholding water for an additional six week period. Soil compaction and drought stress significantly reduced plant height, number of leaves, and leaf area. Although drought significantly inhibited photosynthesis and transpiration, compaction only depressed transpiration. Furthermore, the effects of drought on plant growth, photosynthesis and transpiration were much greater than the effects of compaction. The rate of water loss from compacted plants was lower than the rate from non compacted controls and this may explain the insignificant impact of compaction on photosynthesis. Sorbitol, glucose, and fructose concentrations increased over time during the drought stress period whereas sucrose concentration declined. In well watered controls, sucrose concentration was much higher in leaves of compacted plants than in the leaves on non compacted controls. For most of the sampling dates the leaf sorbitol concentration was lower in leaves on plants growing in compacted soil than in the leaves of those of the non compacted controls. Although interactions between the effects of compaction and drought were highly significant for plant growth variables during the onset of drought, interactive effects on photosynthesis, transpiration, relative water content and carbohydrate variables were inconsistent. Compaction and drought both have major effects on apple plants and the interactions between these two stresses are complex.展开更多
The concentration of sucrose, glucose, fructose, titratable acid, ABA and the activity of acid invertase (AI) were measured in juice sacs of Bendizao mandarin (Citrus succosa Hort), Ponkan (Citrus reticulata Blanco), ...The concentration of sucrose, glucose, fructose, titratable acid, ABA and the activity of acid invertase (AI) were measured in juice sacs of Bendizao mandarin (Citrus succosa Hort), Ponkan (Citrus reticulata Blanco), Miyagawa wase (Citrus unshiu Marc) and Meyer lemon (Citrus meyeri Y). The acid hydrolysis of sucrose in vitro was also studied. The results showed that the sugar content, the ratio of different sugars, titratable acidity, ABA content and the activity of AI were obviously different in four citrus varieties. The sugar content in juice sacs of citrus fruit was related to that of ABA at the late stage of fruit development. The result suggested that ABA played an important role in sugar accumulation in juice sacs of citrus fruit. Bendizao mandarin and Miyagawa wase mainly accumulated sucrose in juice sacs of citrus fruit. Meyer lemon accumulated hexose, and Ponkan citrus was the sucrose-hexose accumulating type variety. In Meyer lemon with high acid degree, the composition of sugar in juice sacs was determined by acid-hydrolysis of sucrose. In Bendizao mandarin, Ponkan citrus and Miyagawa wase with low acid degree, the composition of sugars at the late stage of fruit development was obviously affected by the AI activity.展开更多
Electron microscopic observations revealed that the tissues of poplar ( Populus deltoides Bartr. ex Marsh) apical bud cells, which were fixed by a modified procedure of potassium permanganate fixative, showed a di...Electron microscopic observations revealed that the tissues of poplar ( Populus deltoides Bartr. ex Marsh) apical bud cells, which were fixed by a modified procedure of potassium permanganate fixative, showed a distinct endomembrane organization, in particular, the structural associations of the endoplasmic reticulum (ER) with other membrane systems. The striking findings are that some ER elements were in connection with the nuclear envelopes of two adjacent cells through plasmodesmata, and many ER elements were also associated with mitochondria, plastids, Golgi bodies or the plasma membrane (PM), forming a bridge_like continuum among various endomembrane systems or between nucleus to nucleus. A great number of plasmodesmata existed between cells, indicating a perfectly integrated symplasmic structure in poplar apical bud meristem grown in a long day environment. During the short day_induced dormancy, ER contracted, leading to its disassociation between nuclei, and between the nucleus and organelles/plasmalemma in many cells. After dormancy broke and shoots growth resumed, contracted ER was no longer observed in the apical bud cells. The ER associations with other endomembrane systems and the intercellular communication channels were re_established similar to that of plants before dormancy induction. These observations suggest that ER may play an important role in linking_up between the nucleus and organelles, and between the nucleus and the nucleus (or cell_to_cell), and seemingly coordinating various physiological processes by the bridging_like associations. And the contraction of ER under short_day may result in the growth cessation and the development of dormancy in poplar.展开更多
The stability was studied of the pigment in red pulp plum (Prunus salicina Lindl). The results showed that the pigment had a high resistance to heat and it′s stability seemed to be affected greatly by pH, and red pu...The stability was studied of the pigment in red pulp plum (Prunus salicina Lindl). The results showed that the pigment had a high resistance to heat and it′s stability seemed to be affected greatly by pH, and red pulp plum was suitable to be applied for making acid food. Several kinds of metallic ions including Na + 、Zn 2+ had an effect of reinforcement on its tone, however Fe 3+ had a disruptive effect. Sucrose had no undesirable effect, but vitamin C had a significant undesirable effect. Also the preservative of sodium benzoate had a definite undesirable effect. The pigment showed strong resistance to reducer sodium sulfite but was very weak in resistance to oxidizer hydrogen peroxide.展开更多
文摘Two compounds with strongly insecticidal and fungicidal activity, Kurarinone and Sophoraflavanone G , were isolated from Sophora flavescens Ait under the direction of bioassay, and comfirmed by UV, IR, MS and NMR. The insecticidal activity of flavonoids from Sophora flavescens Ait was first reported here. The study of structure-activity relationship indicated that the methylation of 5-hydroxy on the phenyl ring would decrease the insecticidal and fungicidal activity of flavonoids.
基金The National Natural Science Foundation of China(No. 20377036 30230250 and 30270880)+1 种基金 the Major State Basic Research Development Programme of China(No. 2002CB410806) the Natural Science Foundation of Zhejiang Province(No. 301050) and Hangzhou Committee of Science and Technology(No. 2002112A08)
文摘The dissipation of chlorpyrifos on pakchoi inside and outside greenhouse was studied. The decline curve of chlorpyrifos on pakchoi could be described as first-order kinetic. The experimental data showed that both the hermetic environment of greenhouse and season affected dissipation rates of chlorpyrifos on pakchoi. Chlorpyrifos declined faster outside greenhouse than inside greenhouse. Chlorpyrifos residues at pre-harvest time were below the maximum residue limits(MRLs) fixed in China, whereas the values inside greenhouse were higher than those outside greenhouse by almost 50%. The recommended pre-harvest time established under conditions of open field might not always fit to greenhouse production.
基金supported by the National Natura1 Science Foundation of China(39730340)
文摘The photosynthetic characteristics of strawberry (Fragariaananassa Duch. cv. Toyonoka)leaves under illumination of identical light intensity(55-57% natural light) withdifferent light quality were studied. It was showed that the chlorophyll content,maximal photochemical efficiency of PSⅡ(Fv/Fm), Fm/Fo, amount of inactive PSⅡreactioncenters (Fi-Fo) and rate of QA reduction were positively correlated with the red-light/blue-light ratios, but the chlorophyll (a/b) ratios were negatively correlated withthem. Carotenoid content of the leaves was maximum under the blue film, than under greenfilm, red film, white film and yellow film, and negatively correlated with the red/far-red ratios. The apparent quantum yield (AQY), photorespiratory rate (Pr) and carboxylationefficiency (CE) were also strongly affected by light quality. The photosynthetic rate(Pn) in strawberry leaves under green film was significantly lower than under all otherfilm. Our results suggested that light quality is an essential factor regulating thedevelopment of PSⅡ, and phytochrome and an independent blue light photoreceptor,possibly a cryptochrome, can regulate photosynthetic performance.
文摘Embryogenic calli were induced from the seeds of creeping bentgrass ( Agrostis palustris Huds.) cv. Regent and colonial bentgrass ( Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4-7 days and then co cultivated with Agrobacterium tumefaciens , LBA4404, which contains plasmid vector pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4 D, 12-15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2-3 months of selection, the actively growing calli of 'Regent' and 'Tiger' were transferred to MS medium with 12-15 mg/L PPT and 250 mg/L cefotaxime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.
基金supported by the Natural Science Foundation of Guizhou Province of China(20033019 and 20043025).
文摘A 855 bp cDNA encoding L-galactono-1,4-lactone dehydrogenase (GalLDH) fragment was cloned from fruit of R. roxburghii Tratt by the method of RT-PCR, on the basis of the homologous genes of Arabidopsis thaliana, cauliflower, sweet potato, strawberry, etc. in GenBank. Sequence analysis showed 79-92% identity in nucleotide sequence and 75-87% identity in amino acid sequence to that of strawberry and Arabidopsis thaliana, etc. Northern blot showed that the expression of GalLDH was significantly different in different organs. The transcription level of GalLDH in fruit was significantly higher than that in leaf, stem and root respectively. Furthermore, this expression mode was highly correlated with AsA levels.
基金sponsored by the National Natural Science Foundation of China(39730340)
文摘α-carotene, β-carotene, lycopene, β-cryptoxanthin, zeaxanthin and lutein content of fruits in 53 citrus cultivars were determined using HPLC. In both peel and pulp of citrus fruit, the major carotenoids were lutein, zeaxanthin and β-cryptoxanthin. β-carotene content was relatively low and extremely low was the amount of α-carotene. Among the 53 cultivars tested, lycopene was detected only in pulp of Cara Cara navel orange. Carotenoid content in both peel and pulp of citrus fruit was the highest in Citrus reticulata Blanco and lowest in Citrus grandis Osbeck. Consequently, as far as the health protection value is considered, fruit of Citrus reticulata Blanco ranks probably higher than other citrus fruits. In fruit of most Citrus reticulata varities, β-cryptoxanthin was the main carotenoid component in pulp and its amount approximated that of lutein in peel. Content of lutein, zeaxanthin and β-cryptoxanthin in peel was about 2.515 times that in pulp on the basis of fresh weight. Thus peel was inferred to be the principal location for the carotenoid stock in citrus fruit.
文摘Ca2+ and calmodulin antagonist [trifluoperazine(TFP),N-(6-aminohexyl-chloro-1-naphthalenesulfonamide (W7)] pretreatments were conducted on two eggplant varieties Nongyouqie andErmingqie, which have different heat resistance. The results showed that under 40C(day/night), Ca2+ immersion pretreatment enabled the eggplant seedlings to keep relatively higheractivities of superoxide dismutase(SOD) and peroxidase(POD), reduced the production rate ofsuperoxide anion O2_ and the content of malondialdehyde(MDA), alleviated the damage of reducedglutathione(GSH) and the accumulation of proline (Pro), whereas calmodulin antagonist TFP andW7 immersion pretreatments could lead to more rapid loss of SOD and POD activities, increasethe contents of MDA, Pro and production rate of O2_, aggravate the damage of GSH. Under the samestress condition, heat-resistant variety Nongyouqie was less injured compared to the heat-sensitive variety Erminqie. These data indicated that Ca2+-CaM signal transduction systemmight regulate the heat resistance of eggplant seedlings by controlling the activity of someantioxidant enzymes and the contents of antioxidant substance.
文摘The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (\%Red Fuji/Malus micromalus Makino\%) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46±0.35 nmol g\+\{ 1\}FW and 117 nmol l\+\{-1\} after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day , it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment. Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.
基金This research was partially supported by the Trans-century Training Program Foundation for the Talents by the State Education Commission of China to Dr.Chen Jinfeng,by the National Natural Science Founda-tion of China(301 70644 and 30470120)by National Hi-Tech R&D Program(2002AA241251 and 2004 AA241120)by Tang's Cornell-China Scholar Program and by Pickle Seed Research Foundation of PPI.
文摘Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this species and its first selfed progeny would increase its potential utility in cucumber improvement. With tendrils used as source materials for mitotic analysis, chromosome numbers in all selfed progenies were 2n = 38, confirming chromosomal stability in this synthetic amphidiploid species. Detailed meiotic processes were described by comparing the primary and the selfed amphidiploids. Meiotic abnormalities, such as chromosome lagging, unequal separation, chromosome multi-polarization and polyads were observed frequently in all amphidiploid plants except for the selfed no.8, in which meiosis was arrested prior to metaphase Ⅰ. Generally, the frequency of multivalents was higher and the configurations were more complex in the selfed progenies, demonstrating a more extensive genetic exchange between cucumber and C. hystrix Chakr. Genome separation between cucumber and C. hystrix was observed through prophase Ⅰ to anaphase Ⅰ in both generations of the amphidiploids. Consequently, in addition to n = 19, a new gamete with n = 7 was produced, which was confirmed by the chromosome counts 2n = 14 in the backcrossing progenies from cucumber × amphidiploid mating. Fertility varied among the selfed amphidiploid plants. The selfed plant no.1 was found to have an improved fertility (e.g., pollen staining ability 40.8% and 25.6 seeds per fruit) and then was used as source germplasm in further introgression and gene exchange experiments.
基金funded by the National Natural Science Foundation of China(39730340,30170648).
文摘The dynamics of translocation and partitioning of 14C-phothsynthates, the concentration of sucrose in fruit tissues and the effects of the membrane carrier- and ATPase-specific inhibitors on 14C-sucrose uptake by juice sacs of the satsuma mandarin(Citrus unshiu Marc. cv. Miyagawa wase)fruit were examined at the stage of fruit enlargement and fruit full ripe. Kinetic data of 14C-photosynthate translocation indicated that the rate of photosynthate transport into juice sacs decreased with fruit maturation and sugar accumulation. Along the photosynthate translocation path, i. e. from vascular bundles to segment epidermis then to juice sacs, a descending sugar gradient was observed. With fruit maturation and sugar accumulation in juice sacs, the 14C photosynthate gradient increased, whereas the static sucrose concentration gradient decreased with fruit maturation and sugar accumulation. The higher gradient of specific 14C radioactivity was considered to favor diffusion and sugar transport into juice sacs at the later stage of fruit development. The rate of uptake 14C-sucrose by juice sacs of satsuma mandarin fruit was markedly reduced by PCMBS, EB, DNP and NO3-treatment. The above results suggested the participation of a carrier-mediated, energy-dependent sugar active transport process in juice sacs of satsuma mandarin fruit.
基金supported by the National Natural Science Foundation of China(30230250)the Ministry of Science and Technology of China(2001BA503B08-2).
文摘The influences of different rootstocks on chilling tolerance and physiological parameters in watermelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Compared with own-rooted watermelon seedlings, the grafted watermelon seedlings had lower chilling injury index, lower electrolytic leakage (%), lower malondialdehyde (MDA) content, higher chlorophyll and proline content, and higher activities of superoxide dismutase (SOD), ascorbate peroxidase (AsA-POD) and dehydroascorbate reductase (DR) in the leaves under low temperature stress. There was a considerable difference of chilling tolerance among different grafted watermelon seedlings due to the difference of rootstock chilling tolerance. After low temperature treatment, the grafted seedling with higher chilling tolerance had lower electrolytic leakage (%),lower MDA content, higher proline content and higher activities of SOD, AsA-POD and DR in the leaves compared with the grafted seedling with weaker chilling tolerance. From these, we could conclude that chilling tolerance of watermelon seedlings may be related to higher antioxidative ability and membrane stability in the plants. The chilling tolerance of grafted seedling could be properly evaluated by comprehensive physiological indexes but not a single physiological index.
文摘Greenhouse grown 1 year old potted M.9EMLA apple trees ( Malus pumila Borkh) were subjected to the soil compaction and, after growing under compacted or non compacted conditions for 6 weeks, were subjected to drought stress by withholding water for an additional six week period. Soil compaction and drought stress significantly reduced plant height, number of leaves, and leaf area. Although drought significantly inhibited photosynthesis and transpiration, compaction only depressed transpiration. Furthermore, the effects of drought on plant growth, photosynthesis and transpiration were much greater than the effects of compaction. The rate of water loss from compacted plants was lower than the rate from non compacted controls and this may explain the insignificant impact of compaction on photosynthesis. Sorbitol, glucose, and fructose concentrations increased over time during the drought stress period whereas sucrose concentration declined. In well watered controls, sucrose concentration was much higher in leaves of compacted plants than in the leaves on non compacted controls. For most of the sampling dates the leaf sorbitol concentration was lower in leaves on plants growing in compacted soil than in the leaves of those of the non compacted controls. Although interactions between the effects of compaction and drought were highly significant for plant growth variables during the onset of drought, interactive effects on photosynthesis, transpiration, relative water content and carbohydrate variables were inconsistent. Compaction and drought both have major effects on apple plants and the interactions between these two stresses are complex.
文摘The concentration of sucrose, glucose, fructose, titratable acid, ABA and the activity of acid invertase (AI) were measured in juice sacs of Bendizao mandarin (Citrus succosa Hort), Ponkan (Citrus reticulata Blanco), Miyagawa wase (Citrus unshiu Marc) and Meyer lemon (Citrus meyeri Y). The acid hydrolysis of sucrose in vitro was also studied. The results showed that the sugar content, the ratio of different sugars, titratable acidity, ABA content and the activity of AI were obviously different in four citrus varieties. The sugar content in juice sacs of citrus fruit was related to that of ABA at the late stage of fruit development. The result suggested that ABA played an important role in sugar accumulation in juice sacs of citrus fruit. Bendizao mandarin and Miyagawa wase mainly accumulated sucrose in juice sacs of citrus fruit. Meyer lemon accumulated hexose, and Ponkan citrus was the sucrose-hexose accumulating type variety. In Meyer lemon with high acid degree, the composition of sugar in juice sacs was determined by acid-hydrolysis of sucrose. In Bendizao mandarin, Ponkan citrus and Miyagawa wase with low acid degree, the composition of sugars at the late stage of fruit development was obviously affected by the AI activity.
文摘Electron microscopic observations revealed that the tissues of poplar ( Populus deltoides Bartr. ex Marsh) apical bud cells, which were fixed by a modified procedure of potassium permanganate fixative, showed a distinct endomembrane organization, in particular, the structural associations of the endoplasmic reticulum (ER) with other membrane systems. The striking findings are that some ER elements were in connection with the nuclear envelopes of two adjacent cells through plasmodesmata, and many ER elements were also associated with mitochondria, plastids, Golgi bodies or the plasma membrane (PM), forming a bridge_like continuum among various endomembrane systems or between nucleus to nucleus. A great number of plasmodesmata existed between cells, indicating a perfectly integrated symplasmic structure in poplar apical bud meristem grown in a long day environment. During the short day_induced dormancy, ER contracted, leading to its disassociation between nuclei, and between the nucleus and organelles/plasmalemma in many cells. After dormancy broke and shoots growth resumed, contracted ER was no longer observed in the apical bud cells. The ER associations with other endomembrane systems and the intercellular communication channels were re_established similar to that of plants before dormancy induction. These observations suggest that ER may play an important role in linking_up between the nucleus and organelles, and between the nucleus and the nucleus (or cell_to_cell), and seemingly coordinating various physiological processes by the bridging_like associations. And the contraction of ER under short_day may result in the growth cessation and the development of dormancy in poplar.
文摘The stability was studied of the pigment in red pulp plum (Prunus salicina Lindl). The results showed that the pigment had a high resistance to heat and it′s stability seemed to be affected greatly by pH, and red pulp plum was suitable to be applied for making acid food. Several kinds of metallic ions including Na + 、Zn 2+ had an effect of reinforcement on its tone, however Fe 3+ had a disruptive effect. Sucrose had no undesirable effect, but vitamin C had a significant undesirable effect. Also the preservative of sodium benzoate had a definite undesirable effect. The pigment showed strong resistance to reducer sodium sulfite but was very weak in resistance to oxidizer hydrogen peroxide.
