In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investig...In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.展开更多
By mRNA differential display, eight induced cDNAs were obtained from rice leaves infected with an incompatible race 131 of Magnaporthe grisea, and one of these cDNAs was highly similar to salt-induced mannose-binding ...By mRNA differential display, eight induced cDNAs were obtained from rice leaves infected with an incompatible race 131 of Magnaporthe grisea, and one of these cDNAs was highly similar to salt-induced mannose-binding lectin gene. Using this fragment as a probe, a full length cDNA was isolated from a nice cDNA library, which was constructed using mRNA from the incompatible race-infected leaves. Sequence analysis indicates that the cDNA encodes a protein of 15 kD with 145 amino, acids and shares 96% identity at nucleotide level with MRL and salT, but is identical to MRL at amino acid level. Genomic Southern blotting shows that there are two mannose-binding lectin genes in rice genome. Northern blotting analysis indicates that the gene was strongly and specifically induced in rice leaves infected with the incompatible race, suggesting that the lectin induction be involved in the defense of rice to M. grisea.展开更多
Ammopiptanthus mongolicus (Maxim.) Cheng f. is one of the evergreen shrubs in the desert region of China. In midday its leaves bear photon flux density over 1 500 μmol·m -2 ·s -1 at natural habit...Ammopiptanthus mongolicus (Maxim.) Cheng f. is one of the evergreen shrubs in the desert region of China. In midday its leaves bear photon flux density over 1 500 μmol·m -2 ·s -1 at natural habitat. They show the obvious phenomenon of photoinhibition. For the study of the effects of drought stress on the major protective mechanism against strong light in A. mongolicus leaves, the diurnal variations of photosynthetic rate and chlorophyll fluorescence parameters were investigated under natural conditions with portable photosynthetic measurement system (CIRAS_1) and portable fluorometer (MFMS_2). The experimental results showed that, under normal and drought stress conditions,the net photosynthetic rate ( Pn ), the primary maximum photochemical efficiency of PSⅡ ( Fv/Fm ) and the quantum efficiency of noncyclic electron transport of PSⅡ ( Φ PSⅡ ) decreased obviously at noon (Figs.2,3A,4B). In comparison with plants under normal condition, under drought stress minimal chlorophyll fluorescence ( Fo ) decreased at first and then increased (Fig.3A), non_photochemical quenching ( NPQ ) quickly increased and sustained at a higher level (Fig.4B). This indicated that the major photoprotective mechanism of A. mongolicus leaves was the xanthophyll cycle_dependent thermal energy dissipation under normal condition, while under drought stress, the major photoprotective mechanism was both the xanthophyll cycle_dependent thermal energy dissipation and the reversible inactivation of PSⅡ reaction center.展开更多
[Objective]The aim of this study was to investigate whether communication signal C6-HSL among individual bacteria can influence plant growth and disease resistance ability. [Method]With potato virus-free plantlets as ...[Objective]The aim of this study was to investigate whether communication signal C6-HSL among individual bacteria can influence plant growth and disease resistance ability. [Method]With potato virus-free plantlets as the test materials and C6-HSL as the inducer,the potato＇s growth and the ability of resistance against Erwinia carotovora subp carotovora were tested after being treated by C6-HSL with different concentrations. The effects of C6-HSL on plant landmark defense enzyme activities and H2O2 content in potato leaves were measured especially. [Result]C6-HSL with different concentrations could obviously inhibit the growth rate of root and the number of roots,but had no effect on plant height,number of nodes and leaf size. POD or SOD activity and H2O2 content in plant landmark defense enzymes significantly increased after induction of C6-HSL,but PAL and PPO activity had no obvious change. In the resistant test,potato plants induced by C6-HSL could inhibit the infection of Erwinia carotovora subp carotovora effectively,and its incidence was significantly lower than the control group. [Conclusion]Bacteria AHL can be possibly used as a new kind of plant disease-resistant activator.展开更多
基金Supported by Shaanxi"13115"Public Service Platform Construction Program for Science&Technology Innovation Projects(2010FWPT-17)~~
文摘In order to take advantage of the climate resources more effectively ac- cording to the local circumstances and to plan and develop the citrus industry in Southern Shaanxi more reasonably. On the basis of the investigation of freeze dam- age to citrus occurring in Southern Shaanxi in the winter of 2010, the climatic back- ground for the formation of this freeze damage was analyzed. In combination with the freeze damage indicators during the overwintering period and the harmful accu- mulated cold during the cold wave, indexes for grading the freeze damage in southern Shaanxi were analyzed and verified, and the perspective of grading the freeze damage using the harmful accumulated cold during the cold wave was also presented. Through analyzing the extremely lowest temperature and the harmful ac- cumulated cold in the winter of 2010 and in history at 12 citrus growing counties （districts） in Ankang area and Hanzhong area, the reasons why the freeze damage to citrus during the overwintering period was severer in the west than in the east of Southern Shaanxi were discussed, and the results obtained were basically consistent with the actual situation observed from investigation. Finally, defensive countermea- sures against the freeze damage to citrus during the overwintering period were put forward from several aspects.
文摘By mRNA differential display, eight induced cDNAs were obtained from rice leaves infected with an incompatible race 131 of Magnaporthe grisea, and one of these cDNAs was highly similar to salt-induced mannose-binding lectin gene. Using this fragment as a probe, a full length cDNA was isolated from a nice cDNA library, which was constructed using mRNA from the incompatible race-infected leaves. Sequence analysis indicates that the cDNA encodes a protein of 15 kD with 145 amino, acids and shares 96% identity at nucleotide level with MRL and salT, but is identical to MRL at amino acid level. Genomic Southern blotting shows that there are two mannose-binding lectin genes in rice genome. Northern blotting analysis indicates that the gene was strongly and specifically induced in rice leaves infected with the incompatible race, suggesting that the lectin induction be involved in the defense of rice to M. grisea.
文摘Ammopiptanthus mongolicus (Maxim.) Cheng f. is one of the evergreen shrubs in the desert region of China. In midday its leaves bear photon flux density over 1 500 μmol·m -2 ·s -1 at natural habitat. They show the obvious phenomenon of photoinhibition. For the study of the effects of drought stress on the major protective mechanism against strong light in A. mongolicus leaves, the diurnal variations of photosynthetic rate and chlorophyll fluorescence parameters were investigated under natural conditions with portable photosynthetic measurement system (CIRAS_1) and portable fluorometer (MFMS_2). The experimental results showed that, under normal and drought stress conditions,the net photosynthetic rate ( Pn ), the primary maximum photochemical efficiency of PSⅡ ( Fv/Fm ) and the quantum efficiency of noncyclic electron transport of PSⅡ ( Φ PSⅡ ) decreased obviously at noon (Figs.2,3A,4B). In comparison with plants under normal condition, under drought stress minimal chlorophyll fluorescence ( Fo ) decreased at first and then increased (Fig.3A), non_photochemical quenching ( NPQ ) quickly increased and sustained at a higher level (Fig.4B). This indicated that the major photoprotective mechanism of A. mongolicus leaves was the xanthophyll cycle_dependent thermal energy dissipation under normal condition, while under drought stress, the major photoprotective mechanism was both the xanthophyll cycle_dependent thermal energy dissipation and the reversible inactivation of PSⅡ reaction center.
基金Supported by Natural Science Foundation in Hebei Province(C200600707)~~
文摘[Objective]The aim of this study was to investigate whether communication signal C6-HSL among individual bacteria can influence plant growth and disease resistance ability. [Method]With potato virus-free plantlets as the test materials and C6-HSL as the inducer,the potato＇s growth and the ability of resistance against Erwinia carotovora subp carotovora were tested after being treated by C6-HSL with different concentrations. The effects of C6-HSL on plant landmark defense enzyme activities and H2O2 content in potato leaves were measured especially. [Result]C6-HSL with different concentrations could obviously inhibit the growth rate of root and the number of roots,but had no effect on plant height,number of nodes and leaf size. POD or SOD activity and H2O2 content in plant landmark defense enzymes significantly increased after induction of C6-HSL,but PAL and PPO activity had no obvious change. In the resistant test,potato plants induced by C6-HSL could inhibit the infection of Erwinia carotovora subp carotovora effectively,and its incidence was significantly lower than the control group. [Conclusion]Bacteria AHL can be possibly used as a new kind of plant disease-resistant activator.
