Overwintered leaves influence the growth of the first flush of tea. But it is unclear about the influences of the defoliation of the overwintered leaves on the growth of the second flush of tea.
To clarify this influence, changes in dry weight and the content of total available carbohydrate (TAC) after the defoliation were investigated.
One year-old tea plants grown on a nursery bed (young tea plants) and mature tea plants were used. In young tea plants, all overwintered leaves (all-defoliation) and half of them (half-defoliation) were removed at the developmental stage of three leaves and a bud (April 18). In mature tea plants, new shoots were mechanically plucked remaining about one leaf (May 11) and thereafter the overwintered leaves were removed.
As for young tea plants, total dry weight (excluding the overwintered leaves) increased the most in control plants and the least in all-defoliated plants during the experiment. This relationship was obvious in the dry weight of new shoots (the first flush plus the second flush) and stems.
In mature tea plants, the dry weight of new shoots which plucked within 20 cm x20cm area and the dry weight of 100 shoots were as fllows: control >half-defoliation >all-defoliation. But the number of new shoots was the same in three treatments.
These results show that the growth of the second flush of tea was dependent on the amount of overwintered leaves in both young and mature tea plants.
The content of TAC of new shoots and stems in three treatments of young tea plants increased as time passed. The increase was the most in control plants and the least in all-defoliated plants.
But, the content of TAC of mother stems and roots decreased during the experiment. Its decrease was the most in all-defoliated plants. But the decrease in half-defoliated plants was almost same as control plants.
These results indicate that the consumption of TAC of mother stems and roots might not relate with the amount of the overwintered leaves, and that TAC could not always be utilized for the growth of new shoots effectively.

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This study was carried out to clarify the effects of new leaves left after the 1st cropping on nutrient uptake and quality of green leaves in tea plant during summer period.
Changes in nitrogen content in a plant, and total nitrogen, tannin and amino acids content of new shoots were investigated from the plucking time of the 1 st crop to the 3 rd cropping, using 3-year-old cultivar Yabukita bushes with plucking table similar to mature tea.
The experimental plots were as follows:
Leaf removal treatment : All new leaveson bushes were removed just after the harvesting of the 1 st crop.
Deep plucking : Plucking was made to the last skiffing level in the 1st crop season.
Light plucking : Plucking was made to a height of 3 cm above the last skiffing level in the 1 st crop season.
1. Changes in nitrogen content during the experimental period hardly showed any differen-ces between the plots in root, though the content of aerial parts was continually high in the order of amount of leaves on bushes in each plot.
2. During the growth period of the 2nd crop shoot, both concentration and the amount of nitrogen in the leaves per plant decreased markedly in the plot of leaf removal treatment, but did not decrease in the light plucking and deep plucking plots.
3. In the plot of leaf removal treatment, nitrogen content of all organs except leaves showed the highest value during the shoot growth resting period after the 1 st crodding, and showed the lowest value at the plucking time of the 2nd crop.
Moreover, the greatest and the smallest amount of nitrogen in branches, trunk and thick roots per plant were also observed during the shoot growth resting period after 1 st cropping and at the plucking time of the 2nd crop, respec-tively.
4. Amount of nitrogen absorbed by a plant during the experiment period was almost equall between the three plots.
This trend was also similar in every growth cycle.
5. Total amino acid content of the 2nd crop shoots was high in the order of amout of leaves on the bushes in each plot, but the order reversed in total nitrogen content of the crop shoot.
These relations were irregular in the 3 rd crop.

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This study was carried out to clarify the effects of new leaves left after the 1st cropping on growth of new shoots, dry matter production and carbohydrate economy in tea plant during summer period.
Dry matter weight, yield and carbohydrate content in a plant were measured from the plucking time of the 1st crop to the 3rd cropping, using 3-year-old cultivar Yabukita bushes with plucking table similar to mature tea.
The experimental plots were as follows: Leaf removal treatment: All new leaves on bushes were removed just after the harvesting of the 1st crop.
Deep plucking : Plucking was made to the last skiff ing level in the 1st crop season.
Light Plucking : Plucking was made to a height of 3cm above the last skiffing level in the 1st crop season.
1. As to the increase in dry matter weight of bushes during shoot growth resting period after the 1st cropping, no confirmable difference were observed between the three plots in aerial part, but the plot having larger amount of leaves was inferior to that having smaller one in root.
2. Increase in dry matter weight after the bud opening time of the 2nd crop shoots was great in the order of amount of leaves in each plot.
The differences between the treatments were greater in root than in aerial part.
3. Carbohydrate content in a plant was low in the order of amount of leaves on bushes in each plot during shoot growth resting period after the 1st cropping, but this tendency reversed after the 2nd cropping.
4. As to the amount of carbohydrate per plant, the plot of leaf removal treatment was larger than the other plots at bud opening time of the 2nd flush, but the amount of carbohydrate decreased in the plots having small amount of leaves on bushes following the 2nd cropping, and great differences of that among the plots were observed after that.
5. Both carbohydrate content and amount of carbohydrate per plant decreased rapidly in all plots during the growth period of the 2nd crop shoot, especially, this tendency was more notably in the plot of leaf removal treatment.
6. As to the growth in the 2nd crop shoots, carbohydrate reserve in leaves contributed more greatly in deep plucking and light plucking plots than the other plot, while the carbohydrate reserves in trunk and root contributed more largely in the plot of leaf removal treatment than in the other plots.
7. In the 2nd crop season, the plot of leaf removal treatment was smallest in yield by or-dinary plucking, but greatest in the weight of all new shoots on the bushes.
In the 3rd crop season, light plucking plot having the largest amount of leaves provided the smallest yield.

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[in Japanese]

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1. Methods of frame formation to shorten the period of making mature tea bush were inves-tigated. Three different types of varieties in plant shape (Yabukita :erect type, Yamakai intermediate type and Kanayamidori :spread type) were chosen for this experiment. They were planted in single rows with an intarval of 1.8m and 0.3m distance between plants.
2. The design of 38type multi-factors was established by including 3 factors having each 3 levels. The factors and levels are as follows:(1) Varieties: Yabukita, Yamkai and Kanaya-midori.
(2) Heading height at the time of planting: 15, 20 and 25cm above the ground level.
(3) Cutting height at one year after planting: 5, 10 and 15cm above the heading level at the planting time.
3. Height of plant in var. Yabukita was superior to that in var. Kanayamidori, but the spread of plant was inferior during the experimental period of 5 years.
4. The yield obtained from a unit erea of tea field was increased with increase of the spread of plant. From the result, it was thought that the increase of the plant spread balanced with the increase plant height and this was important for shortening the period of making mature tea bush.
5. In the plot in which the plants were cut at high level, both height and spread of the plants was greater than those of the other plots.
6. The ratio of spread to height of tea plant was culculated as a representation of plant shape. The ratio was low in var. Yabukita and high in var. Kanayamidori during, the frame formation perid. In the plot in which the plants were cut at high level, the ratio was lower than those of the other plots.
7. From the experiment above mentioned, it is thought that the following methods are good for frame formation in each variety.
a) The plants are headed back to a height of 15-20cm at the planting time, and the new growthes are cut back to a height of 10cm above the previous cutting level at one year after planting for erect type variety such as Yabukita.
b) The plants are headed back to a height of 20-25cm at the planting time and the new growthes are cut back to a height of 10cm above the previous cutting level at one year after planting for the spread type variety such as Kanayamidori.

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To find out effective fungicides and application time for control of Gray blight of Tea plant caused by Pestalotia logiseta Speg., 31 fungicides were tested by methods (a) formation of inhibition zone by fungicide on conidia seeded PDA (Potato Dextrose Agar), (b) mycelial growth on PDA containing fungicide and (c) application of fungicide to tea bush after plucking.
By thr method of the formation of inhibition zone by fungicide on conidia-seeded PDA, the following fungicides formed inhibition zone around the filter paper containing 1000 ppm of the fungicide; thiophanatemethyl, chlorothalonil, poly-carbamate, captafol, benomyl, chinomethionate, milneb and isoprothiolane. But polyoxine, oxy-carboxin, EDDP, copper oxychloride, copper hydroxide and copper sulfate didn't form inhibition zone at 1000 pm.
By the method of mycelial growth on PDA containing the fungicide, on the PDA containing iprodione and dichlofluanid the mycelia didn't, grow at 10 ppm. Howevere, they grew even on the medium containing 100 ppm phenazine oxide.
In the field 31 fungicides were tested by spraying 200 litters per 10 a to tea bushes after plucking, because the fungus invaded the plant through wounds of the leaf or the young shoot. The following fungicides were effective by application within a few hours after plucking: thio-phanatemethyl (75%WP) 1:1500-10000, chlorothalo-nil (75%WP) 1:600-800, benomyl (50%WP) 1:2000 -3000, captafol (80%WP) 1:2000-5000, thiophanate methyl-oxine copper (35%-40%WP) 1:600-800, benomyl-chlorothalonil (10%-6% WP) 1:500-700, dichlofuluanid (50%/WP) 1:600-800, fluoroimide (75%WP) 1:800-1500, kasugamycin-copper oxychloride (5%-75.6-%WP )1:500-800, captan (80%WP) 1:600, guazatine (25%/AS) 1:1000-2000 and kasuga-mycin (2%AS) 1:1000. The following ones were not effective even by spraying within a few hours after plucking; chlorothalonil (75%WP) 1:1500, anilazine (50%WP) 1:800, triadmefon (25%WP) 1:1000, lime sulfer 1:50, validamycin (3%AS) 1:1000, iprodione (50%WP) 1:1000, dithianon (70%WP) 1:1000, milneb (700%WP) 1:1000, isoplo-tiolane (40%EC) 1:1000, polycarbamate (75%WP) 1:1000, copper sulfate (47.5%WP) 1:200, Bordeaux mixture (6 grams of quicklime and 6 grams of copper sulphate in 1 litter of water) and lime water (6 grams of quicklime in 1 litter of water).
Thiophanatemethyl (70%WP) was one of the most effective fungicides, and the solution diluted at 1:2000 controled the disease successfully by application within 3 days after plucking and the solution diluted at 1:5000 was also effective by spraying within one day.
Chlorothalonil (759%WP) 1:600-800 and captafol (80%WP) 1:2000 were not effective by application at one day after plucking, so it was necessary that these fungicipes be sprayed within a few hours for control of the disease.

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The average losses of ascorbic acid (AsA) in green tea infusions were about 10.3% at 50°C for 60 min and about 47.9% at 70°C for 60 min. The activation energy for ascorbic acid degradation in tea infusion ranged from 12 to 17 kcal/mol. The average value was 14.7 kcal/mol. AsA in the first infusion was more stable than that in the third infusion. The stability of AsA in the third infusion increased when sodium cyanide was added to the infusion.
Since AsA in tea infusion was more stable than AsA dissolved in distilled water, it was suggested that tea infusion contained protect-ing compounds of AsA. Polyphenol fraction extracted with ethyl acetate, pectin fraction precipitated with 50% ethanol, and water soluble fravonoid fraction precipitated with aceton from tea infusion depressed the degradation of AsA. When authentic catechins were added to the AsA solution, epicatechingallate and epigallocatechin gallate depressed the degradation of AsA. However, epicatechin, epigallocatechin and catechin did not show the effects on the stabilty of AsA. Copper ion and ferrous ion accelerated the degradation of AsA. Chelating agents such as sodium cyanide and ethylenediamine tetraacetic acid depressed the degradation of AsA in the solution containing Cu⁺² and⁺² Fe. Moreover AsA in the solutions containing chelators was more stable than that of tea infusion.
From these results, it is speculased that AsA in tea infusion is stabilized by the compounds that have an interaction with metal ion, such as gallate of catechins.

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Crude green tea was stored under four conditions ; A, at -70°C for 18 months, B, at 25°C for 3 months and then at -70°C for 15 months, C, at 25°C for 6 months and then at -70°C for 12 months, and D, at 25°C for 18 months.
Crude lipids were extracted with CHCl₃ -MeOH (2 : 1) and separated into three lipid classes by the silicic acid column chromatography using three kinds of solvent system, and the separation of individual lipid components of each class was carried out by thin layer chromatography. The amounts of lipids were calculated from the density of spots developed by spraying with 50% sulfuric acid and heating.
The result indicated that the content of total lipid, especially glycolipid, decreased as the extention of the period of storage at 25°C, and such lipids, MGDG, DGDG, SQDG and PC, have a tendency to decrease during storage.

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Time course of the defoliation of old leaves and its varietal differences (Yabukita, Yutaka-midori and Benihomare) in frame formed tea plants were examined from April to October.
Each variety showed one or two peaks of the defoliation from April to June.
The time of the start of the defoliation was earlier in Yabukita and Yutakamidori than in Benihomare (late variety).
The amount of the defoliation was the least in Yutakamidori and the most in Benihomare.
Differences in the defoliation between the frame formed plants and the natural shape framed plants were discussed.

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