OBJECTIVETo study the effect of different water stress mode on photosynthesis characteristics of Aconitum barbaturnm, aimed at providing the theoretical basis for cultivating this kind of plant for the arid area.

METHODThe transplanted seedlings of A. barbatum were processed with fixed partial root zone drying(TI) ,alternate partial root zone drying(T2) and both partial root zone irrigation (T3) for three cycles,and relative parameters were measured.

RESULTThe net photosynthetic rate (Pn) in the treatment of T2 gradually increased and was higher than that in the treatment of T3 about 6.53%, mainly effected by non-stomatal factors. The water use efficiency (WUE) was higher than that in the treatments of T3 about 25.21%, while the transpiration rate (Tr) and the stomatal conductance was lower than those in the treatment of T1 and T3 separately. The maximum net photosynthesis rate (Pmax),the apparent quantum yield (AQY) and the dark respiration rate (Rd) were higher than those in comparison condition slightly.

CONCLUSIONThe alternate partial root zone drying is worth promoting vigorously, and it shall be a rational way to cultivate the A. barbatum under woodland.

Aconitum ; physiology ; Dehydration ; Photosynthesis ; physiology ; Plant Roots ; physiology ; Plant Stomata ; physiology ; Plant Transpiration ; physiology ; Seedlings ; physiology

The purpose of this experiment was to study the effects of different shading conditions on the growth,physiological characteristics and biomass allocation of Polygonatum cyrtonema,which offered a theoretical basis for its cultivation.Different light environments(100%,80%,60% and 35% light transmittance) were simulated with shading treatments.Growth and photosynthetic indexes of P.cyrtonema were measured and the variances were analyzed.The results show that shading decreased superoxide anion radical(O-·2)production rate and hydrogen peroxide(H_2O_2) accumulation,kept the activity of SOD,POD and CAT enzyme at a high level.Furthermore,The content of chlorophyll a and chlorophyll b,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),maximal photochemical efficiency of photosystem Ⅱ(Fv/Fm),photochemical quenching index(q P) and effective quantum yield of photosystem II(ΦPSⅡ) of P.cyrtonema were increased while the intercellular CO2 concentration(Ci),Foand NPQ were decreased by shading.Shading is beneficial to P.cyrtonema growth,can increase the total biomass P.cyrtonema.The allocation proportion of biomass on the aerial portion of P.cyrtonema increased but underground parts decreased with increasing shading conditions.In this study,P.cyrtonema can grow well in shading conditions,shading is beneficial to the formation of the yield and quality of the rhizomes of P.cyrtonema,especially in 65% light transmittance.
Biomass ; Chlorophyll ; Chlorophyll A ; Photosynthesis ; Plant Leaves ; Plant Stomata ; Plant Transpiration ; Polygonatum ; growth & development ; physiology ; Sunlight

OBJECTIVEChilling tolerance of salicylic acid (SA) in banana seedlings (Musa acuminata cv., Williams 8818) was investigated by changes in ultrastructure in this study.

METHODSLight and electron microscope observation.

RESULTSPretreatment with 0.5 mmol/L SA under normal growth conditions (30/22 degrees C) by foliar spray and root irrigation resulted in many changes in ultrastructure of banana cells, such as cells separation from palisade parenchymas, the appearance of crevices in cell walls, the swelling of grana and stromal thylakoids, and a reduction in the number of starch granules. These results implied that SA treatment at 30/22 degrees C could be a type of stress. During 3 d of exposure to 7 degrees C chilling stress under low light, however, cell ultrastructure of SA-pretreated banana seedlings showed less deterioration than those of control seedlings (distilled water-pretreated).

CONCLUSIONSA could provide some protection for cell structure of chilling-stressed banana seedling.

Adaptation, Physiological ; Cold Temperature ; Microscopy, Electron ; Musa ; physiology ; ultrastructure ; Plant Leaves ; ultrastructure ; Plant Transpiration ; Salicylic Acid

Through indoor and field comparative experiments, the properties of membrane type leaf evaporation inhibitors and its effects on photosynthesis of and compatibility and synergistic of pesticide were studied. The evaporation inhibitors and were chosen to investigate the suppression of water evaporation and the compatibility with pesticides. The effect of evaporation inhibitors on photosynthesis of leaves was determined by the chlorophyll fluorescence imaging system. The results showed that water evaporation of leaves of different leaf age were evidently suppressed after treated with evaporation inhibitor. The inhibitor was well compatible with pesticide and effectively improved the pesticide efficacy，and had no significant effect on chlorophyll fluorescence parameters. It is concluded that the evaporation inhibitor has good compatibility with the pesticide, and has remarkable effect of restraining moisture evaporation, which make it can be used for reducing the dosage and improving the efficacy of the pesticide in the field of
Chlorophyll ; analysis ; Lycium ; drug effects ; physiology ; Pesticides ; chemistry ; Photosynthesis ; Plant Leaves ; drug effects ; physiology ; Plant Transpiration

In this study,the leaves of autumn-sown Angelica dahurica var. formosana from Sichuan province in different growth years was used to explore the fitting model of photosynthetic response curve and the different photosynthetic physiological characteristics between annual and biennial A. dahurica var. formosana from Sichuan province. The results showed that the fitting model of the optimum light response curve of the leaves of A. dahurica var. formosana from Sichuan province with different growth years was all rectangular hyperbolic correction model. The light saturation points were 1 600,1 700 μmol·m-2·s-1,the light compensation points were17. 98,52. 23 μmol·m-2·s-1 in the leaves of annual and biennial plant,respectively. The diurnal variation curves of net photosynthetic rate,transpiration rate and stomatal conductance in the leaves all acted as a single peak value wave. The daily mean values of net photosynthetic rate and transpiration rate in the leaves of biennial plant were significantly higher than that of annual plant. There was no significant difference in daily mean stomatal conductance. The net photosynthetic rate was significantly positively correlated with stomatal conductance in both of the different growth years. The net photosynthetic rate of annual and biennial A. dahurica var. formosana from Sichuan province had extremely significant and significantly negative correlation with the intercellular CO2 respectively. The transpiration rate of annual plant was positively correlated with the effective photosynthetic radiation intensity and air temperature,but had significantly negative correlation with the intercellular CO2 concentration. The transpiration rate of biennial plant had extremely positive correlation with the effective photosynthetic radiation intensity,and negatively correlated with the intercellular CO2 concentration. In conclusion,the photosynthetic efficiency of the leaves in biennial plant of A. dahurica var. formosana from Sichuan province was higher than that in annual plant,but the ability to utilize weak light was lower than that of annual plant. It should be planted in the sunny field.
Angelica ; physiology ; Carbon Dioxide ; China ; Photosynthesis ; Plant Leaves ; physiology ; Plant Transpiration ; Seasons ; Temperature

Freshwater shortage is the main problem in Heilonggang lower-lying plain, while a considerable amount of underground saline water is available. We wanted to find an effective way to use the brackish water in winter wheat production. Surface mulch has significant effect in reducing evaporation and decreasing soil salinity level. This research was aimed at comparing the effect of different mulch materials on winter wheat production. The experiment was conducted during 2002~2003 and 2003~2004. Four treatments were setup: (1) no mulch, (2) mulch with plastic film, (3) mulch with corn straw, (4) mulch with concrete slab between the rows. The result indicated that concrete mulch and straw mulch was effective in conserving soil water compared to plastic film mulch which increased soil temperature. Concrete mulch decreases surface soil salinity better in comparison to other mulches used. Straw mulch conserved more soil water but decreased wheat grain yield probably due to low temperature. Concrete mulch had similar effect with plastic film mulch on promoting winter wheat development and growth.
Agriculture ; methods ; China ; Plant Transpiration ; Seasons ; Sodium Chloride ; analysis ; Soil ; analysis ; Temperature ; Triticum ; growth & development ; Water ; chemistry

OBJECTIVETo study the effect of water content in soil on physiological characters and yield of Artemisia annua.

METHODThe pot experiment was applied and activity of protective enzyme, biomass and artemisinin accumulation were measured under different water treatments.

RESULT AND CONCLUSIONThe results showed that contents of osmotic adjustable substances, activity of protective enzyme, biomass and artemisinin accumulation were greatly affected by water content in the soil. Under water stress the water content in leave decreased, relative plasmalemma permeability increased, proline quickly accumulated to promote water retaining capability of cell, POD, CAT and SOD cooperated to reduce lipid peroxidation and reduced cell damage, and biomass decreased. At the seedling stage, the content of artemisinin and yield reached the maximal when the water content in soil was between 50%-55%. At the beginning of the branching stage, the content of artemisinin was the highest at the water content of 50%-55%, while the yield reached the maximal at the water content of 70%-75%. At the end of branching stage, the content of artemisinin was the highest at the water content of 40%-45%, while the yield reached the maximal at the water content of 60%-65%. In conclusion, the optimum water content in soil was between 50%-55% at the seedling stage, at the branching stage, higher water content was beneficial for the higher yield.

Antimalarials ; analysis ; pharmacology ; Artemisia annua ; chemistry ; physiology ; Artemisinins ; analysis ; Biomass ; Plant Leaves ; chemistry ; Plant Transpiration ; Seedlings ; Soil ; analysis ; Water ; Water Movements

OBJECTIVETo study the effect of water stress on the content of scutellarin and caffeate in Erigeron breviscaps.

METHODFv/Fm, N content, as well as the content of scutellarin and caffeate under three water grads were measured.

RESULT AND CONCLUSIONFv/Fm of the plant decreased significantly in 8% and 23% water treatment, that proved drought and waterlogging occurred. Under the two conditions, the contents of N were lower but the contents of active constituents were higher than those under 15% treatment. The results support the carbon-nutrient balance hypothesis and the "stress effect hypothesis" for the formation of geo-herbs.

Apigenin ; metabolism ; therapeutic use ; Caffeine ; pharmacology ; Dehydration ; drug therapy ; therapy ; Droughts ; Erigeron ; chemistry ; growth & development ; metabolism ; Gene Expression Regulation, Plant ; Glucuronates ; metabolism ; therapeutic use ; Plant Preparations ; therapeutic use ; Plant Transpiration ; drug effects ; Plants, Medicinal ; chemistry ; Temperature ; Water ; physiology