Abstract
1. Potted plants of guayule were grown for a period of 5 months during the spring, summer, and fall in natural light of full intensity, and other plants were subjected to lower intensities obtained by means of cloth filters. Half the total number of plants were supplied with nutrient at intervals to maintain soil fertility, while the remainder were grown in relatively infertile soil. During the winter the experiment was transferred to a greenhouse and continued under controlled temperature conditions. 2. A 25% reduction in light intensity was associated with a 36% reduction in the amount of rubber produced by plants grown in relatively fertile soil. Further reduction of light was associated with a corresponding decrease in the percentage and absolute amount of rubber stored. The percentage and absolute amounts of rubber produced by plants grown in infertile soil were relatively low and not greatly affected by shading. 3. A reduction of 25% in light intensity reduced the dry weight of stems and roots of plants grown in fertile soil by 14.5%; and more extreme reduction in light further retarded vegetative growth. Of plants grown in infertile soil, the greatest leaf weight was produced by those exposed to 75% of full sunlight, but moderate shading had no appreciable effect on the weight of stem and roots. 4. Two-thirds of the leaves of plants grown in direct light remained green throughout the winter, but only one-third of those on deeply shaded plants remained green and functioning. 5. Reduced light intensity (44%-75% of unscreened light) favored seed production during June, July, and August. Shading was less effective in stimulating seed production during September. Decrease in light intensity was associated with decrease in the proportion of large seeds produced. Withholding inorganic nutrients was associated with an increase in the proportion of small and a decrease in the proportion of large seeds. Reduction in light intensity was not associated with an appreciable change in seed quality. 6. The cross-sectional area of stems was not significantly affected by a 25% reduction in intensity; but further reduction was associated with marked decrease in stem thickness, cross-sectional area of pith, xylem, bark, and fiber tissue in the bark. 7. Percentage areas of the various stem tissues were essentially constant both in the different light intensities and with the two fertilizer treatments. The percentage of bark was not correlated with changes in percentage of rubber. 8. Under full light intensity, the percentage of resin in plants grown with a limited nutrient supply was equal to that of plants to which nutrients were supplied; and with shading those subjected to a limited nutrient supply contained a higher percentage of resin than did those afforded nutrients.
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Claims 20
Claim · model-written summary
A 25% light reduction was associated with 36% less rubber in fertile soil.
Verbatim
t0“Guayule”
e0“A 25% reduction in light intensity was associated with a 36% reduction in the amount of rubber produced by plants grown in relatively fertile soil”
Claim · model-written summary
Further light reduction decreased percentage and absolute rubber amount.
Verbatim
t0“Guayule”
e0“Further reduction of light was associated with a corresponding decrease in the percentage and absolute amount of rubber stored”
Claim · model-written summary
In infertile soil, rubber percentage and amount were low and little affected by shading.
Verbatim
t0“Guayule”
e0“The percentage and absolute amounts of rubber produced by plants grown in infertile soil were relatively low and not greatly affected by shading”
Claim · model-written summary
A 25% light reduction reduced stem and root dry weight in fertile soil by 14.5%.
Verbatim
t0“Guayule”
e0“A reduction of 25% in light intensity reduced the dry weight of stems and roots of plants grown in fertile soil by 14.5%”
Claim · model-written summary
More extreme light reduction further retarded vegetative growth.
Verbatim
t0“Guayule”
e0“more extreme reduction in light further retarded vegetative growth”
Claim · model-written summary
In infertile soil, leaf weight was greatest at 75% sunlight.
Verbatim
t0“Guayule”
e0“Of plants grown in infertile soil, the greatest leaf weight was produced by those exposed to 75% of full sunlight”
Claim · model-written summary
Moderate shading had no appreciable effect on stem and root weight in infertile soil.
Verbatim
t0“Guayule”
e0“moderate shading had no appreciable effect on the weight of stem and roots”
Claim · model-written summary
Two-thirds of leaves under direct light remained green through winter versus one-third under deep shade.
Verbatim
t0“Guayule”
e0“Two-thirds of the leaves of plants grown in direct light remained green throughout the winter, but only one-third of those on deeply shaded plants remained green and functioning”
Claim · model-written summary
Reduced light favored summer seed production.
Verbatim
t0“Guayule”
e0“Reduced light intensity (44%-75% of unscreened light) favored seed production during June, July, and August”
Claim · model-written summary
Shading stimulated seed production less during September.
Verbatim
t0“Guayule”
e0“Shading was less effective in stimulating seed production during September”
Claim · model-written summary
Lower light intensity was associated with a smaller proportion of large seeds.
Verbatim
t0“Guayule”
e0“Decrease in light intensity was associated with decrease in the proportion of large seeds produced”
Claim · model-written summary
Withholding inorganic nutrients increased the proportion of small seeds.
Verbatim
t0“Guayule”
e0“Withholding inorganic nutrients was associated with an increase in the proportion of small and a decrease in the proportion of large seeds”
Claim · model-written summary
Withholding inorganic nutrients decreased the proportion of large seeds.
Verbatim
t0“Guayule”
e0“Withholding inorganic nutrients was associated with an increase in the proportion of small and a decrease in the proportion of large seeds”
Claim · model-written summary
Light reduction was not associated with appreciable seed-quality change.
Verbatim
t0“Guayule”
e0“Reduction in light intensity was not associated with an appreciable change in seed quality”
Claim · model-written summary
A 25% light reduction did not significantly affect stem cross-sectional area.
Verbatim
t0“Guayule”
e0“The cross-sectional area of stems was not significantly affected by a 25% reduction in intensity”
Claim · model-written summary
Further light reduction decreased thickness and areas of stem tissues.
Verbatim
t0“Guayule”
e0“further reduction was associated with marked decrease in stem thickness, cross-sectional area of pith, xylem, bark, and fiber tissue in the bark”
Claim · model-written summary
Percentage areas of stem tissues were essentially constant across light and fertilizer treatments.
Verbatim
t0“Guayule”
e0“Percentage areas of the various stem tissues were essentially constant both in the different light intensities and with the two fertilizer treatments”
Claim · model-written summary
Bark percentage was uncorrelated with rubber percentage.
Not reportedDirection
Verbatim
t0“Guayule”
e0“The percentage of bark was not correlated with changes in percentage of rubber”
Claim · model-written summary
Under full light, resin percentage was equal under limited and supplied nutrients.
Verbatim
t0“Guayule”
e0“Under full light intensity, the percentage of resin in plants grown with a limited nutrient supply was equal to that of plants to which nutrients were supplied”
Claim · model-written summary
Under shade, limited nutrients produced a higher resin percentage than supplied nutrients.
Verbatim
t0“Guayule”
e0“with shading those subjected to a limited nutrient supply contained a higher percentage of resin than did those afforded nutrients”