Hisatomi Harada

Variations in Nitrogen Uptake and Nitrate-Nitrogen Concentration among Sorghum Groups

Abstract Nitrogen uptake and nitrate-N concentration in forage sorghums, which are related to ground water pollution or feed quality under conditions of crop fertilization by only animal wastes, were examined. Seventy-four genotypes of sorghum and Sudan grass were tested. They were classified into 4 groups; grain type and dual purpose type sorghums (6 and 13 genotypes, respectively, Sorghum bicolor Moench), sorgo type sorghum (21, S. bicolor), Sudan type sorghum (22, S. bicolor × S. sudanense (Piper) Stapf), Sudan grass (12, S. sudanense). There was a strong correlation between dry matter (DM) yield and N uptake, with the sorgo type producing the highest DM matter yield and showing the highest N uptake. Nitrate-N, which causes nitrate poisoning of ruminants, was detected mostly in the stem of all the genotypes. The nitrate-N concentration based on DM could be calculated accurately by multiplying the nitrate-N concentration of stem on a fresh matter basis by the DM partitioning ratio of stem divided by the DM concentration of stem. The grain type and the dual purpose type of sorghums with dry stem showed the lowest nitrate-N concentration because these plants had a lower DM partitioning ratio of stem and higher DM concentration of stem. Sudan grass and Sudan type sorghum with the genetic background of Sudan grass showed higher nitrate-N concentrations owing to their ability to accumulate nitrate-N.

Natural Background Levels of Trace Elements in Wild Plants

Abstract Natural background levels of trace elements in wild plants were investigated. Firstly, the validity of the analytical methods using inductively-coupled plasma mass spectroscopy after wet digestion with HNO3 and HF was confirmed. Measurement results for standard plant material were almost the same as the certified values of Cu, Zn, Mo, Cd, Sb, and Pb. Additionally, other 6 elements, Be, Cs, La, Ba, n, and Bi were also analyzed simultaneously. Secondly, 87 plant species were collected from our Institute, and the basic statistical parameters of the element concentrations were calculated. Although distribution of the concentrations of Cu, Zn, Mo, Ca, Sb, and Pb displayed as logarithms was considered to be more symmetrical than that of normal data, only distribution of Cu and Cd fitted to a normal curve by chi-square test. Variance of element concentration was larger among species than within a species. Thirdly, plants and soils from 16 sites located in the central and eastern parts of Japan were coll...

Natural background levels of trace elements in wild plants: Variation and distribution in plant species

Abstract The natural levels of trace elements in wild plants of Japan were investigated. Wild plant shoots were collected at 16 sites from central to eastern Japan. The concentrations of various trace elements, namely, Be, Cu, Zn, Mo, Cd, Sb, Cs, Ba, La, Tl, Pb, Bi, in the 410 samples of 209 species were simultaneously analyzed by inductively coupled plasma mass spectroscopy. Geometric means were calculated with the data arranged according to plant species, some basic statistical parameters were calculated. Distribution of all the elements except La showed significant logarithmic normal pattern. The average concentrations of Sb, Cs, Ba, La, Pb, Bi in Pterophyta were higher than those in Anthophyta. The concentrations of Be, Cu, Ba, La, Pb were higher in Dicotyledonopsida than in Monocotyledonopsida and the reverse was true for Mo concentrations. Cu, Cd, Cs concentrations were higher in Sympetalidae than Archichlamiidae. Concerning plant families, Moraceae and Cyperaceae contained more Mo, Compositae, Polygonaceae, Liliaceae more Cd, Saxifragaceae more Cs, Polygonaceae more TI, the families belonging to Pterophyta showed higher Cd, Sb, La, Pb, Bi concentrations.

Management of nitrogen fertilizer application rates based on soil nitrogen fertility with the goal of lowering nitrate nitrogen concentrations in Sudangrass (Sorghum sudanense (Piper) Stapf)

Abstract High levels of nitrate nitrogen (NO3-N) in forage crops can poison ruminants. To promote stable production of Sudangrass (Sorghum sudanense (Piper) Stapf) with safe NO3-N levels, we investigated the influence of soil nitrogen (N) on Sudangrass yield and on NO3-N concentrations, and we propose a fertilizer management strategy based on soil N levels for a regime based on the application of cattle manure composted with sawdust. We used the available N content determined by incubation of fresh soil as an indicator of soil N. Both the yield and NO3-N concentration of Sudangrass increased with increasing available N. The NO3-N concentrations in the first grass harvest remained lower than 2 g kg−1 (dry-matter basis), which represents the critical level to avoid nitrate poisoning of ruminants in Japan, with an available N content of 40 mg kg−1 (dry-soil basis), the level where yield remained approximately stable without additional N fertilizer. The NO3-N concentration increased linearly with increasing available N and exceeded the critical level when available N exceeded 50 mg kg−1. Under low levels of N (less than 30 mg kg−1), the target yields for the first grass harvest, with safe levels of NO3-N, could be obtained with the application of 10 g N m−2 in fertilizer, lower than the recommended rate of 15 g N m−2. The NO3-N concentration was higher in the second grass harvest under the same levels of soil N with an available N of 40 mg kg−1 or more. The NO3-N concentrations in the second harvest exceeded the critical level when the available N was 40 mg kg−1. These results indicate that available N content is an effective indicator for the stable production of Sudangrass with acceptably low NO3-N concentrations.

A simple method for estimating the nitrate nitrogen concentration based on dry matter in standing sorghum (Sorghum bicolor Moench) using stem juice test and dry matter content

Abstract A simple method was developed for estimating the nitrate nitrogen (NO3-N) concentration in standing sorghum (Sorghum bicolor Moench) crop at maturity. In the method, the concentration of NO3-N in whole plants on a dry matter basis can be accurately estimated by multiplying the concentration factor (CF, NO3-N concentration of stern on a fresh matter basis) by the dilution factor (DF, dry matter partitioning ratio of stern divided by the dry matter content of stern or fresh matter weight of stern divided by the dry matter weight of whole plant). CF was linearly correlated with the NO3-N concentration in stern juice squeezed from stern discs with a thickness of 1 cm obtained by cutting horizontally at a location corresponding to a ratio of 25% to the total stern length. CF can be estimated by multiplying the NO3-N concentration in stern juice by a factor of 0.68 or 0.53 for grain and dual purpose types or sorgo type, respectively. The values of the coefficients of determination (R 2) of the linear regression were above 0.7. When DF was plotted with the dry matter content of whole plants (DM%), regression curves were obtained for both sorghum types with R 2 > 0.8. The equations were as follows: DF= 0.00721X 2-0.503X + 10.72 for grain and dual purpose types, DF=0.00445X 2 -0.337X + 8.86 for sorgo type, where X is DM%. The NO3-N concentrations estimated by multiplying CF by DF enabled to predict the measured NO3-N concentrations with an R 2 of 0.873.

Content of Be, Ga, Sb, Cs, Ba, La, Tl and Bi in wild plants: screening for accumulating plants

Wild plants from 87 species consisting of 6 trees, 71 herbs and 10 ferns were collected and examined for Be, Ga, Sb, Cs, Ba, La, Tl and Bi. Background levels were expressed by geometrical mean, median, 25%, and 75% values. Some plants accumulated these elements at high concentrations. The accumulating ability was expressed by the accumulation index (AI) calculated as follows; (concentration to evaluate — 75% value)/(75% value — 25% value). According to AI, several ferns were accumulator plants for all elements excluding Be. Common thistle (for La), buckwheat and broadleaf dock (for Tl) were also considered to be accumulator plants.

Characterization of proton pumping and ATPase activities in microsomal fractions from barley roots

Abstract The properties of proton pumping and ATPase activities of barley (Hordeum vulgare L. cv. Daisen-gold) roots were investigated using microsomal preparations and partially purified ATPase. Quenching of acridine orange fluorescence was used to measure the proton pumping activity of microsomal vesicles collected on Dextran T-70. Addition of ATP·Mg3+ caused the quenching of the fluorescence. The quenching returned to the original level by addition of protonophores ((NH4)2SO4, gramicidin). The proton pumping activity was dependent on KCl, and was inhibited by KNO3. The ATPase enzyme was solubilized from microsomal preparations with 0.2% Zwittergent 3–14, and partially purified by DEAE-cellulose column chromatography. The ATPase activity was dependent on Mg2+, and inhibited by vanadate. The activity of the purified ATPase which was derived from the plasma membranes in the microsomal preparations, was insensitive to K+, and stimulated by Ca2+ in the absence of Mg2+. These results suggest that the proton ...

Isolation and characterization of a novel Arabidopsis thaliana mutant that shows low nitrate concentration in shoots

Abstract A novel Arabidopsis thaliana mutant that shows a low concentration of nitrate in shoots was isolated from an ethyl-methanesulfonate-mutagenized M2 population. In the mutant, the nitrate concentration in the shoots was reduced to 45–61% of that in the wild-type plants when plants were grown hydroponically at a different range of external nitrate. When grown in solid media containing 5 mmol L−1 nitrate, the fresh weights of shoots and roots in the mutant were approximately 62% and 67%, respectively, compared with those of the wild type. The mutant did not show any difference in in vitro nitrate reductase activity from wild-type plants and net nitrate uptake in the mutant was 22% lower than that in wild-type plants. Genetic mapping analysis revealed that the mutation was mapped near the bottom of chromosome 1.

Impact of genomics on the study of plant nutrition. 7. Practical use of naturally occurring genomic variation in plant nutrition

(Jpn. J. Soil Sci.Plant Nutr., 77, 343–349, 2006)

Reconstitution and Characterization of Plasma Membrane H^+-ATPase Activity from Rice Roots

Abstract Plasma membrane vesicles were purified from rice (Oryza sativa L. cv. Nippon-bare) roots using aqueous two-phase partitioning. The purified vesicles were solubilized with deoxycholate and reconstituted with soybean phospholipids by gel filtration. lonophores stimulated the ATPase activity of the reconstituted vesicles. Inhibition of the ATPase activity by vanadate increased from 77 to 93% by the reconstitution. These results indicate that the reconstituted vesicles were sealed and the vanadate-sensitive ATPase activity was purified during the reconstitution. The ATPase activity of the reconstituted vesicles was characterized. Only ATP was effectively hydrolyzed. Apparent Km value was 1.26 mM. Divalent cations were necessary for the activity, and their stimulation was in the following order: Mg2+>Fe2+>Mn2+, Co2+≫Ca2+. Half-maximal inhibition by vanadate occurred at 5 μM. Monovalent ions stimulated the activity, and cations and anions were effective in the order of NH4 + >K+, Rb+>Na+> Li+> choline+...