| Cryptotaenia japonica Hassk (Umbelliferae), a perennial herbaceous plant, isnative to China and Japan. It usually favors humid eco-environment. This plantspecies is both an edible and pharmaceutical plant. C. japonica is a popularvegetable in Japan and usually served as salad or prepared in soup. But in China itis usually cooked and then served. This plant can be cultivated year round in greenhouses. And due to easy handling, C. japonica is also grown hydroponically. Itsnutritious and pharmaceutical nature are of great concerns among agriculturalistsand farmers. The aromatic ingredient in the whole plant also has commercial andindustrial potential. To the best of my knowledge, only a few studies have beenaddressed to C. japonica as yet. And these studies have been concentrating on thenutrient elements, the volatile constituent, the pharmaceutical purposes andtoxicology, and its morphological anatomy and seed characteristics.The paper made detailed studies on irradiances, nutrient solutionconcentrations and NaCl stress of C. japonica, which could afford some basicscientific information for the industrialization. The results were as follows:1. The effects of shade on the growth, photosynthetic characteristics,chlorophyll fluorescence parameters and the peroxidation of membrane lipid ofCryptotaenia japonica were studied under differing irradiances (15,35,60, and100%of full irradiance). In full irradiance, Cryptotaenia japonica exhibited atypical decline in PNduring midday, which was not observed in other shadingtreatments. This indicated a possible photoinhibition for Cryptotaenia japonica inhigh irradiance. Diurnal patterns of stomatal conductance (Gs) was remarkablysimilar to those of PNat each shade treatments, and the intercellular CO2concentration (Ci) had the opposite change trend. Cryptotaenia japonica growingin60%of full irradiance exhibited the highest plant height, stem diameter, LA and biomass. The initial fluorescence (Fo) value was lowest in60%of full irradiance.The maximal fluorescence (Fm), potential activity of PSII (Fv/Fo), and themaximal photochemical efficiency of PSII (Fv/Fm) values were highest in60%offull irradiance and lowest in15%of full irradiance. The MDA content in15and100%of full irradiance were higher. CAT, POD and SOD activities increased firstand than declined in15and100%of full irradiance as prolonging of growth time,and the activities in60%of full irradiance were in the relatively low statusindicating that the productive rate of activated oxygen was low. Therefore, takingthe above many factors into consideration together, Cryptotaenia japonica shouldbe cultivated in moderate-shade environment such as60%of ambient irradiance tomeet the ever-increasing demand of leaf and also to increase its developingpotential.2. In order to explore suitable nutrient concentration for the growth ofCryptotaenia japonica seedlings, the effects of six different concentrations ofYamasaki nutrient solution (1/12s、1/10s、1/8s、1/4s、1/2s and full strength) on thegrowth, antioxidase activities and chlorophyll fluorescence parameters ofCryptotaenia japonica seedlings were investigated. The results showed that thehighest Cryptotaenia japonica seedlings’ growth factors (plant height, leaf area,stem diameter, fresh and dry weights of shoot, fresh and dry weights of root, freshand dry weights of plant) were observed at1/8s Yamasaki nutrient solution.Seedling indexes increased firstly and then declined with increasing nutrientsolution concentration. In addition, the maximal values of seeding indexes wereobserved in the1/8s nutrient solution, which was significantly higher than those atany other concentrations. When the concentrations of nutrient solution were among1/12s~1/8s, the activities of POD, CAT and SOD increased gradually withincreasing nutrient concentration, while MDA content gradually decreased.However, POD, CAT and SOD activities, as well as MDA content, demonstratedthe contrary trend at1/8s~s nutrient concentration. When the concentration ofnutrient solution was close to1/8s, POD, CAT and SOD were highest, while MDAcontent was the lowest. The contents of chlorophyll a, chlorophyll b and totalchlorophyll increased at lower nutrient concentrations but decreased at higher concentrations, e.g. physiological parameters were highest at1/8s nutrient solution.Under1/4s~full strength Yamasaki nutrient solution, the initial fluorescence (Fo)value was higher than those at1/12s～1/10s, while the maximal fluorescence (Fm),potential activity of PSII (Fv/Fo), and the maximal photochemical efficiency ofPSII (Fv/Fm) were lower than those under1/12s~1/10s. Fo value was lowest at1/8s nutrient concentration, while the values of Fm, Fv/Fo, Fv/Fm were the highest.Our findings suggested that nutrient concentration played dual roles onCryptotaenia japonica seedlings, i.e. at lower nutrient concentrations, seedlinggrowths were accelerated with increasing concentrations due to alleviated nutrientstress, while seedling growths were inhibited with increasing concentrations athigher nutrient concentrations due to enhanced nutrient stress.1/8strengthYamasaki nutrient solution was the optimal concentration for the growth ofCryptotaenia japonica seedlings.3. The different concentrations of NaCl making stress on Cryphtotaeniajaponica of salt injury index, MDA, proline and chlorophyll and several antioxidantenzymes activity were studied by using the method of hydroponically-culture. Theresults showed that, with the increase of salt concentration and the prolonging timeof NaCl stress, the salt injury index, the contents of MDA and praline increaseddifferently but the whole contents of chlorophyll decreased in varying degrees,moreover, the activities of SOD, POD, CAT were increased firstly and thendeclined. Our findings suggested that Cryphtotaenia japonica had some adaptability to moderate NaCl stress, but the NaCl stress with high concentration andlong time might lead to severe damage on Cryphtotaenia japonica. |
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