Utilization of inorganic nitrogen for the timothy leaf spot fungus, Cladosporium phlei de Vries, was examined in this study. When the fungus was cultured in glucoseammonium nitrate medium supplemented with thiamine and pyridoxine, the pH in the medium lowered gradually during the first 17 days and thereafter rose. A similar experiment was conducted using the medium excluding any vitamin and essentially the same result was obtained. The lowering and rising of pH at the early and later stages were explained in terms of preferential utilization of ammonium ion prior to active utilization of nitrate ion.

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Sucrose and phlein hydrolases were demonstrated to exist in the haplocorm of timothy. The hydrolyzing activities were examined using the soluble and insoluble fractions. The soluble fraction was cell sap freed from mitochondria, and the insoluble fraction was fibrous materials including cell walls. The activities were mainly found in the insoluble fraction. However, it remains to be investigated whether the hydrolases are adsorbed to the insoluble fraction during the preparation of haplocorm homogenate. Neither the soluble nor the insoluble fraction was active to inulin.

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In the community of grass sward, individual plants are competiting with one another and inferior plants gradually fade away in the progress of competition. Thus the status of distribution of stubbles in grass swards seem to be changed by the extent of competitive pressure among individuals.In this research, the relation between stubble size and the distance among stubbles and the disposals of different size of stubbles were investigated in fall of 1971, in order to know the status of distribution of stubbles in orchardgrass sward. The swards investigated in this study have passed for three years after sowing, and the vegetational structure (density, basal coverage and the distribution of stubbles etc.) have been changed by the different amounts of fertilizer application. The results were summarized as follows ; 1) In this study, the diameter of stubble was adopted in order to indicate the stubble size. High correlation was shown between the diameter of stubble and the number of tillers in a stubble (Fig.2) 2) About same size of two stubbles being adjacent each other, the relation of the distance between stubbles and the diameter of stubbles were examined. There were high correlation between the distance and the diameter of stubbles, and following regression was obtained ; D=1.177R^<1.111> γ=0.949 (D…distance between stubbles, R…diameter of stubbles) 3) In swards which various size of stubbles were distributed, it has an inclination that large stubbles situated in the distance with one another and small stubbles situated near or among large stubbles (Fig.4 and 5). 4) From the results described above, it was discussed that density and basal coverage in grass sward should be described not only the number and the degree of coverage in unit area, but also relationship between the stubbles size and the distance between stubbles.

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Kinetics of the cell wall hydrolysis by cellulase and its application to estimate the nutritive value were investigated. Following experiments were made to establish the technical procedure. 1. Cell wall samples from two samples of Italian ryegrass were hydrolysed by 1.0% cellulase solution dissolved in pH 4.0 acetate buffer solution for 15〜600 min. 2. Successive treatments of samples with neutral detargent and cellulase were investigated 0.5g air dried sample passed in 1.0mm screen was weighed into reflexing apparatus. After 1-hr boiling with neutral detergent, residual cell wall was washed with water, acetone and acetate buffer and was hydrolysed by 1.0% cellulase for 30〜240 min. 3. Successive treatment were applied to 34 grass and/or grass-legume mixture hays and cubes to estimate the nutritive value of forage. In this experiment cellulase hydrolysis time was 4-hr. Conclusions are summarized as follows from the experiment described above. 1. The structural carbohydrates of the cell wall are divided into at least two fractions by cellulase hydrolysis, one of which is not lignified nor crystallized constituent (NCL region), and the other fraction is associated with lignin and crystallized constituent. (CL region). The reaction of cellulase hydrolysis in both regions was first order reaction and the rate constant of NCL resion showed a higher mean value than that of CL region by 3.5 times. The amount of the NCL region was closely related to the quality of the forage. It appears that the carbohydrates of NCL region may be easily fermented in the rumen, second to the soluble carbohydrates in the cellular contents. 2. In the case of the successive treatments with the neutral detergent and cellulase it would be assumed that cellulase activity is depressed by the residual sodium lauryl. sulfate after the pretreatment. Bearing this problem in mind, washing method was investigated to eliminate completely the sodium lauryl sulfate. By washing it with water-acetone-water-buffer solution, 3-3-6-3 times respectively, no effect was observed of detergent on the cellulase activity. 3. Between the dry matter digestibility or TDN contents in vivo and DM disappearance (%) by successive treatments above mentioned in 34 samples, highly significant correlations were obtained: γ=0.904, 0.880 (P<0.01) respectively.

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To estimate the changes in digestibilities of growing grasses, continuous digestion experiments were conducted using goats. To test the validity of the method a model system was made in which several mixtures of alfalfa and Italian ryegrass hay at the ratios of 5:0, 4:1, 3:2, 2:3, 1:4 and 0:5 were fed in turn at 3-days intervals. Since the crude protein digestibilities of these hays had been obtained, the theoretical digesti-bilities could be compared with the experimental digestibilities. From this model experiment it was concluded that the time lag between feed intake and the associated fecal output did not affect the digestibilities to any significant extent (Table 1). The energy and crude protein digestibilities of the fresh field materials of alfalfa, perennial ryegrass, and tall fescue were estimated by the continuous digestion experiments using Japanese meat-type goats of about 10kg body weights. In the first trial the animals fed perennial ryegrass and tall fescue did not survive until the end of experiment, since the feeding level of fresh grasses was too low (about 0.9% of body weight daily). Only the animals fed alfalfa could survive at the same feeding level. In the second trial the amounts of grasses equal to 1.6% of body weight daily were fed from May 11 to June 7 at the cutting intervals of 3 days. The height of grasses on May 8 was about 12 to 15cm (eight days of regrowth). From 20 individual digestibilities of 2 animals per each component of a grass, a regression equation between the cutting date and digestibilities was deduced. The daily rates of decline in the digestibilities of energy of alfalfa, perennial ryegrass, and tall fescue were 0.41, 0.54, and 0.32%, and those in the digestibilities of crude protein of alfalfa, perennial ryegrass, and tall fescue were 0.35, 0.45, and 0.31%, respectively, during the period of May 11 to June 7 (Table 3).

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In orchardgrass, Dactylis glomerata L., resistance to stem rust race II, Puccinia graminis PERS., was inherited tetrasomically, and there resistance was fully dominant to susceptibility. Parental clone, later assumed as duplex (AAaa), produced 985 resistant and 26 susceptible seedlings when self-pollinated. This was considered to be 35:1 ratio (0.50<p<0.70). In progeny tests of 65 self-fertile first generation inbred plants, 30 produced only resistant seedlings, 24 produced both resistant and susceptible seedlings in a ratio approximating 35:1, and 11produced both resistant and susceptible seedlings in a raio approximating 3:1. The ratio approximating 3:1 was detected more easily and more accurately than the ratio approximating 35:1. Then x^2 for fit of observed to expected was tested as 54 (AAAA+AAAa+AAaa):11 Aaaa, when expected was 50.1:14.9. This fitted 27:8 ratio by 0.20<p<0.30. Stem rust resistance will be a usefull marker for further observations of the genetic structure of orchardgrass.

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