Part III

cupboard. 70 A PEIMER OF BOTANY. ((7) flaxseed. (f) some plant with which you are familiar. Name parts of plants which cannot make starch or oily- matters. Give a reason for such failure ; tell the case of leaves and similar plant organs in darkness. Write a statement about the way plants store foods, and name two plants which store them in different tissue masses. USE OF RESERVE MATERIALS. -- 1. Copy the following statement : The sweet taste of kernels of growing corn shows that the starch has changed into sugar. (rt) What taste has a kernel of green corn ? What does the second part of the statement show ? (5) Which words name food materials ? Define the word starch in the statement. (c) Explain what is meant by the word sugar. Starch is changed into sugar for the nourishment of growing plants. 2. In each of the following, mention the change which has taken place, and mark the words that made -- you aware of it : The sugar beet is eaten. The piece of cane is sweet. THE PHYSIOLOGY OF PLANTS. 71 The bud has a sweet taste. There is sugar in an onion. -- In the following, fill the blanks with words that show why starch is changed to sugar ; Starchy seeds feed with . Starch is too to penetrate masses. Watery diffuse throughout the . The sweet of maple shows the presence of changed to . When reserve material is used, the starch suffers a chang-e exactly like that upon leaving chloroiJhyll grains. It becomes a fluid food again. Exercise I. -- Use in sentences, starch, sugar, oil, squash seed, potato, chlorophyll grains, buds, twigs, bulbs. Observe the qualities of underground stems, bulbs, roots, and fruits which you see at home, and try to rightly express the food materials which they store, and how the plants break up their reserve foods before making use of them. Exercise II. Use words that denote plant foods, as starchy substances^ rigari/ substances^ watery substances^ in statements which show whence these foods are drawn, where manufactured, and whether stored in a solid or watery state. ; 72 A PRIMEK OF BOTANY. -- Cautions. 1. All pai-ts of plants may digest starchy store reserve material^ and use food matters for their tis- sues ; as, the root eats ; pond scum grown in the dark digests food ; a flower petal uses food material. m 2. Starch-making goes on the green parts . of plants only; much starch is made iii the leaves; no starch is produced hy flowers. 3. Parts of plants ivhich are not green do exactly like chlorophyll-hearing parts in the darkness; that is, they digest ivhatfood they can obtain. But you see how dependent they are upo7i the green organs. Exercise III. (With the Teacher.) O:^^ The teacher may vary the tasks by a familiar talk, or by some simple puzzle play about plants. The following method, adapted from a text-book upon another subject, is a very good one. A. Each of you think of a cupboard of reserved plant food, of its taste or its quality. Do not tell any one what it is. As you name its taste (or use words which express its size or appearance or other qualities), I will write the words, and the class may see how many can guess the name of the cupboard. B. When the pupil called upon has finished describing the object, refer to the items on the board, and ask, Who can guess what it is that "grows underground" "may be big or little " ; "is full of starch and is good to eat"; that is "small and hard and shiny"; "holds very much oil" ; "is not nice to taste or handle"; "is very small"; "bread is made of it"? When the cupboard has been named, refer to the board and verify or correct. THE PHYSIOLOGY OF PLANTS. 73 c. Refer to the words and describe the plants to which they belong. Review the tissues of which the plants are made. E. TEMPERATURE. A lowest temperature. A highest temperature. A best temperature. There are three temperatures which should be studied for every plant; namely, lowest, best, highest. Plants can live only between the lowest and highest temperatures. 1. What is the highest plant temperature ? The temperature beyond which activity ceases. 2. What is the best temperature ? The temperature at Avhich the plant thrives perfectly. 3. What is the lowest temperature ? That below which activity ceases. 4. Tell the effect upon house plants of the temperature of,- a January da}^ boiling water, a hot oven, a cold March wind. The lowest temperature for plants is from the freezing point of icater to 60� above it. Some plants live at a 74 A PRIMER OF BOTANY. lower temperature than others. The temperature varies^ too, for the different parts of the p)lant ; thus, a root will live at a lower temperature than a leaf. The highest temperature for plants is fror)i 95� to 120�, varying for different plants, aiid for different parts of the same plant. 5. Measure the temperature and describe the plant life of pond water in spring, when water plants begin to grow ; of cold springs in which plants are found. 6. Notice in the newspaper the average daily temperature while tree buds are opening in the spring. Compare it with the average daily temperature during the ripening of the fruit. The best temperature varies more than the lowest or the highest. Some plants pass their lives in air hut little -- above the freezing point ; thus, The red snow plant often covers the snow in higher latitudes. It grows on mountain summits in low latitudes. 7. Plant in two pots seeds of barley or Indian corn. Leave one pot in a cold cellar, and put the other in a warmed room. To find the best temperature, compare the growth of the plants in the two pots. Why 8. are the leaves of trailing arbutus stiff, homely, and unattractive ? 9. What reduces early water plants to a brown scum on water, or to a brown coat on stones? THE PHYSIOLOGY OF PLANTS. 75 The best temperature for laiid plants varies just as in the case of the lowest and highest. The best temp)erature for roots is lotver than that for the plant above ground^ a7id the best temperature for steins and leaves is lower than that for fruits. -- 10. Mention two plants that need, a very high temperature. a very low temperature, a middling temperature. 11. Name a plant which outlives early autumn frosts. What does its extended life prove about its best temperature ? Test Exekcise. What have you learned about the temperatures of plants ? Apply the three temperatures in statements which show how vitally they affect plant life. The Death of a Plant. What happens when the temperature falls below a certain point? Ans. The plant dies. Explain its death. A plant dies when the substance of the protoplasm stiffens. Loss of power to absorb water results, and the cell-walls lose shape, and collapse. The tissues of watery plants and of most fleshy ones suffer most quickly in extremes of temperature. -- 76 A PRIMER OF BOTANY. -- Underline the names of leaves and stems which feel the first frosts keenly : a squash leaf, a potato stem, leaves of the butternut, an apple leaf, rose geraniums, violets. The results beyond the limits of the highest temperature are exactly like those produced by too cold air. Either result is a species of burn. In either case, watery cells are the first injured. -- Notes. (r/) Plants asleep in dry seeds can be kept in almost any degree of low temperature ; but when they break their tight blanket and sprout, the tissues of the sprout absorb much water, and the plant dies in a temperature lower than about 30� above the freezing point. Sprout beans or peas, and prove this by experiment. (6) The boundary systems of the ripened parts of native trees and shrubs usually endure extreme- -- ly cold w eather ; but The young shoots and tender' leaves of large trees and shrubs are easily killed by spring frosts ; as, the developing horse-chestnut bud. any bursting winter bud. Tell what temperature, medium, low or high, is the best -- temperature for these plants : red seaweed, kelp, moulds, the apple tree, magnolias, a cactus, edelweiss, a prickly pear plant, life everlasting. THE PHYSIOLOGY OF PLANTS. 77 Which of the above possess boundaiy systems suited to northern winters ? Which of the above would be most quickly affected by extreme temperatures; i.e., temperatures beyond the highest or lowest limits which bound the plant's activity? If the plants are watery, give a special reason for their sensitiveness. Cliemical cliaiigres begin at once, as soon as extreme cold or heat touches watery ceHs. The tissues lose form very rapidly. Write statements describing the apparent best temperature for three plants at home, or in the school yard, or in a park. -- Things to Kemember. 1. That a plant freezes because the umter in the cell-walls and in the protoplasm turns to icicles. You have been taught that this water is not pure, but holds many plant foods. It ivill bear a lower temperature than tvill pure water. Very rarely is any plant comp)letely frozen. 2. Many frozen plajits 2vill survive if thaived slowly. Many fleshy tissues (fruits} are not injured by freezing, but by rapid thawing. Thaw frozen apples in ice-ivater. Tests. (1) 1. Mention a temperature, and name three plants whose best temperature it appears to be. 2. Change the temperature so that it will show (a) the lowest temperature for the plants named ; (b') the highest temperature for their activity. 78 A PEIMEE OF BOTANY. (2) Illustrate hoAv the best temperature varies for roots, -- leaves, and flowers of the same plant ; how it varies for two water plants, two land plants. Locate the plants given as examples. Give your idea of their lowest and highest temperatures, judging from the climates in which they are found. (3) 1. Define the words lotvest, best, and highest temperatures, 2. Copy from a book or newspaper the names of five plants. 3. Study their location and habits, and write after each what you think may be their lowest, best, and highest temperatures. -- 4. Describe variations of lowest and highest temperatures, and name, (a) that part of the plant which will bear a lower temperature than other parts. (5) that part of the plant which requires a higher temperature than other parts. 5. What is the lowest temperature for all plants ? 6. What is the highest temperature for plant activity? (4) Describe the death of a plant. Why do watery tissues suffer quickly? Mention similar results from widely different conditions. THE PHYSIOLOGY OF PLANTS. 79 -- In what cases will plants endure very low temperatures? Describe plant life in, a seed, winter bud, tree trunk or branch. Why do few plants freeze solidly? dition of the water in their tissues. -- serve, Describe the con- Tell how to pre- a chilled shrub. a frozen cabbage. a frost-bitten apple. CHAPTER VIII. MOKE PHYSIOLOGY OF PLANTS. LIGHT. -- 1. Read the following : (1) House plants turn toward the light. (2) Moulds grow without the aid of light. (3) Fruits and flowers can develop in darkness. (4) Green plants directly depend upon light. (5) Light helps them to make starch. (6) Without starch green plants starve. 2. Mention the word which is the lesson. 3. What plants live by it ? 4. What plants can live without it ? 5. Are such plants of a high or low order ? 6. Name the parts of a plant which grow to full size with- out light. 7. What plant food can be made by light only ? Of what importance is this food? To what sort of plants indispensable ? L Without Hg-lit, green plants starve, for tliey manu- facture starch hy it only. THE PHYSIOLOGY OF PLANTS. 81 -- Note. Plants which get their starch from other plants can live in the dark. Plants which live upon decaying matters grow and perfect fruit in caves and cellars. Tests. (1) Search dark cellars and host plants for the following, -- and describe their condition when found : (a) fungi. (5) mildew. (<?) rust. (tf) yeast plants. (e) slime moulds. -- Tell which of the following must have light : verbena blossoms. a leaf of verbena. a root. stems of Indian corn. flowers of Indian corn (tassels and silk). smut. (2) Box up a flower-bearing end of a melon vine, exclude all light, and watch results. Report the development of the flowers in respect of size, color, shape, and strength. How can winter pears and apples ''ripen" in the house? -- -- 82 A PKIMER OF BOTANY. B. MOVEMENTS OF PLANTS. -- Mention visible movements of the following plants, and tell when they occur : four o'clock, sensitive plant, What is true of all plants ? leaves of clover, dandelions. 11. Every plant can move itself. Many plants are much more active than the lowest animals; as, sensitive plants, some cassias. What is sufficient to irritate a sensitive plant? is it most irritable ? Ans. In its younger tissues. Where -- Note to Teacher. Grow sensitive plants in the schoolroom for study. Seeds may be had for a few cents, and are easily grown. Is the sensitive plant an exception in the plant world, or an intensified example of a power owned by every plant ? Describe the movements of, oxalis, parsley, a strawberry geranium, sunflowers, the water lily, fuchsia leaves. Name some plant, and describe its movements toward the light, away from the light, or its manner of adjusting itself for sleep. When a seed sprouts, how does its root always move ? THE PHYSIOLOGY OF PLANTS. 83 Simde^v. III. When a seed sprouts, the little root tries to move -- in circles ; thus, Sprout a bean, and fasten it carefully under a cork in a bottle of water. Watch the movements of the protruding rootlets. IV. The tip of the root is sensitive to pressure, and when it touches any object, bends from it. 84 A PRIMER OF BOTANY. Therefore tbe root tip guides the root through the ground, avoiding stones and hard lumps. V. Root tips are sensitive to moisture, and are always leading the roots to wet places in the soil. Write five statements about the movements of roots of plants, and describe the route they take through the earth. Tell how the revolving motion of the root aids it to find soft places in soil. Tell whether roots are often found in true spirals, and think of a reason why they are more or less de- formed. VI. Every growing shoot and every flower stalk en- -- deavors to grow in spirals ; thus, a bean stalk, a pea plant. -- Tell how the branches of the following grow : an acacia tree, a pine, a maple, a geranium shrub, a rose tree, blackberry bushes. Write two statements about the movements of growing stems of trees and shrubs, and of annual plants. QAnwaal means living but one season ; as, migno- nette.) Describe the real movements of any large tree, as to both stem and root, and state whether we can see these movements, or only their results. We do not knoiv why groiving imrts of plants above ground revolve. There may he preferences in air currents and densities of the air. The ptlant may seek these as specially good points for spreading out its leaves. THE PHYSIOLOGY OF PLANTS. 85 Exercise I. Name a plant whose name signifies " turning to the sun Give another, that lives away from the light. Mention three plants which change position at night. Make notes of day positions of the leaves of five plants. Make similar notes of the night posi- tions of the same plants. Are all plants able to move ? Name parts of plants that seem motion- less. Name others that prove they are in motion. Mention a plant with visible movement. Tell two reasons for the spiral move- ments of a root. Sundew Leaf holding a Fly. Exercise II. 1. Draw a sketch of the day and night positions of a daisy. 2. Study a fuchsia in a window, and write an account of its movements toward the light. 3. Sow seeds in a window box, and carefully study the tiny plants that appear. Make notes of your work, and embody these notes in a composition about -- plant movements, marking particularly, (a) any stems or runners that bend away from the light. By experiment prove the plant's persistence in its habit. -- -- 86 A PRIMER OF BOTANY. (^) leaves and stems which turn towards the light. ((?) differences of position during waking and sleeping states. The bean family are excellent examples for this study. 4. Sprout cabbage seeds, and examine the first leaves of the seedlings. These first leaves, by the way, are always called in botanical works cotyledons. Mark, (rt) their positions by day. (/>) their positions by night. (/) if they invariably rise at night. c. MORE ABOUT THE MOVEMENTS OF PLANTS. Describe the particular form of movement which you -- found was possessed by, oxalis, the strawberry geranium, the heliotrope, roots of beans. Mention the general law of movement of all growing roots and stems. The law of progress in sx>irals is inodifiecl by certain influences; as, At night the leaflets of oxalis bend down and cling about the stalk. At night clover leaflets fold to one side and bend upwards. THE PHYSIOLOGY OF PLAXTS. 87 The leaves of most plants take a different position at night. Their growth in spirals may be hindered by the withdrawal of strength-giving liglit. Strong light stimulates * plants so much that they bend towards it. Their perfect progress is thus destroyed. Dictate a statement which shall describe a motion common to all plants. Change the statement so as to correctly give two hindrances to the plant's power to de- scribe circles. How does the turning stems to the light prove their origi- nal circular movement ? Leaves and stems move in a zigzag course toward the li*�ht.* Is the course ever a straight line ? Pitcher Plant. Nearly a straight line, at times, in a flood of light. Give from your observation the amount of light (as common daylight, noonday sun, hot rays on glass, etc.) necessary to turn a stalk or leaf from its course, to bend it visibly toward the light, and to draw it out in a straight line. Pin a sprouting bean with the rootlets upward. Which way will they grow ? -- * !N'oTE TO Teacher. Ex.^\3iui stimulates. 88 A PKIMER OF BOTANY. Roots of ordinary plants Avill always bend toward the -- earth ; as, the rootlets of strawberry plants. the edible roots which we draw from the ground. VII. Turning toAvard the light and turning toward the earth both depend on the continuous motion of the plant. This motion is as tireless as are our heart-beats, during every minute of the plant's life. Hard substances in the soil will modify the spiral movements of roots, and places of much moisture will have the same deflecting fascination which light has for stems and leaves. -- Gkavitation, a force ^vhic^l keeps yon. and me upon the -- earthy draws roots down., and modifies their circular sweep). Test I. How do leaves and stems usually move toward the light ? Which way will roots always bend ? -- Make a statement about the influence which modifies growth in spirals in the case of, a root, a clover leaf, heliotrope, cotyledons of cabbage, flowers of four o'clocks, leaves and flowers of the dandelion. Change the statement so as to mention some other plant. -- Read the following list of plants, date palms, trailing arbutus, anemones, orchids, lilacs, seaweeds. and tell in each case towards what the root bends. THE PHYSIOLOGY OF PLANTS. 89^ -- Correct, (r^) Plants are motionless. (5) The thick-walled tissues of plants are most sensi- tive. ((j) The sensitive plant does not shrink when touched. (c?) Leaves and stems hurry in straight lines toward the light. Test II. -- Tell what parts of what plant, move in circles. are weakened by the withdrawal of sunlight, are greatly influenced by bright light, seek soft places in the soil, lead roots to spots of moisture. Test III. Describe the movements of the root and stem of a heliotrope, and state what is the basis of any sort of particular movement of any plant. What certain rule for the direction of ordinary rootlets ? -- AVhat causes this certainty? Define gravitation, and use it in a written statement about, ((?) three objects in the schoolroom ; as, chair, desk. (/)) three objects in the street, or in a shop, or in the school-yard. (c) a horse hauling a load or drawing a carriage ; a cow standing under a tree. (cZ) teacups upon the table; the china in the cupboard; the stove upon the floor. (^) water in the ocean, or in a river, or in a Avell. (/) the roots of plants. 90 A PKIMER OF BOTANY. In other statements, describe its liindering force with regard to the law of plant movement in curves. Give reasons for other hindering forces to .the spiral movement of roots. How do leaves and stems usually move to the light? When greatly stimulated ? Give the general law of plant movement. Name three modifying influences. Give an example of each. -- Describe the position during sleep of, leaves of ^ ^^' j ^f ( clover, cotyledons of ] ^^^^7' ( cabbage, sensitive plants, flowers of the water lily. Use these descriptions in statements (a) telling the modi- fying influence, (6) describing the plant action under the influence. Review. ORAL. 1. What per cent of water in a higher flowering plant? In seaweed ? What parts of plants are abundantly supplied with water? What absorbs it? Why? Tell its oflice in cells. In cell-walls. How 2. Define a cell-ivalL and where do cell-walls thicken ? 3. Describe the condition of water in a plant body during winter. Give three disturbing agencies in summer. How is Avater a plant material? How is water -- absorbed by, deep-sea plants? land plants and parts of plants above water ? ; THE PHYSIOLOGY OF TLANTS. 91 -- 4. Explain these terms : evaporation, " circulation of sap," breathing-pores, perennials, movement of water in plants, annuals. 5. Define plant food, and use it in a statement. 6. Give two statements about plant food, mentioning (a) one food common to the animal and plant worlds (^) habits of eating of different plants. 7. Which holds the most food materials, well water or pond water? What process aids the transportation of food? Which order of plants has a complex diffusion of food materials ? 8. What is starch? Where is starch-making done? Name other products made in the green parts of some plants. 9. Tell how (�) starch is of use, (5) its change upon leaving its factory, (c) its change again before storage. Tell ((x) why any food material is stored, (5) upon what the organs which have no chlorophyll depend. 10. (a) Define lowest^ best^ and highest temperatures. (5) Give the lowest, best, and highest temperatures for plants, (c?) Illustrate how the best temperature varies for different parts of the same plant. (d} Would green plants starve without light ? (e) Name a cousin of green slime. Ans. Med S7101V plant. (/) What plants can live in the dark ? (//) Has every plant the power of nidti^ai? 92 A PKIMER OF BOTAISY. (/i) Name the plant having this power in the highest degree. (z) Give the real direction of plant movement, (y) Mention three modifying influences over plant movement. BLACKBOARD. 1. Write a proof of the abundance of water in some seaweeds. 2. Write the composition of the growing point of a plant. 3. Write a statement that tells (�) agencies which dis- turb water in a cell, (^) how vacancies in cells are -- filled. 4. Write the relative rapidity of evaporation in, a wet day, a dry noon, the night. Write a definition of breathing-pores, with their location. Use the word breathing-pores in a statement about a function which they directly control. 5. Write carefully the reason of tlie flow of sap from the sugar maple. 6. Write the route of water in plant structures. Write Three Things to Remember about water in plants. -- 7. Write statements telling whence the following obtain their food : puff balls, pond lily, Venus's fly-trap, smuts, red seaweeds, lichens, primroses, mosses. THE PHYSIOLOGY OF PLANTS. 93 8. Describe in writing the diffusion of plant food, telling (a) a reason for the unequal transportation of foods through the tissues, (^) what great food holds man}^ other foods in solution ; that is, ynixed inside its otvn structures. -- 9. Use in written statements, starch, sugar, chlorophyll grain, squash seed, potato, bulbs. 10. Write a paragraph (a) about the apparent best tem- perature of three common plants