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Wonder of botany

- Familiar wisdom and works of the green -

Cat: SCI
Pub: 2003
#: 1808

Osamu Tanaka (田中修)

Wonder of botany 不思議の植物学
  1. Introduction:
  2. What food do plants east?:
  3. How do plants struggle with stress?:
  4. How do plants defend their bodies?:
  5. How do plants anticipate seasons?:
  6. How do plants manage reproduction?:
  1. 序:
  2. 何を食べているのか:
  3. ストレスと闘う:
  4. 体を守る:
  5. 季節を先取りする:
  6. 生殖に工夫を凝らす:

; abscisic acid; Absciss layer; Antibacterial agent; Beautiful color of flowers; Bulb of flowers; C3/C4 plant; Chlorophyll; Chloroplast; Emission spectrum; Far-red spectrum; Five senses of plants; Florigen; GMO; Grafting; Green leaf; Heliotropism; Heterosis; Hyponica; Light response; Overwinter bud; PEP; Photoperiodism; Photosynthesis; Phytochrome; Pistil; Pollen; Pollinosis; Regenerative ability; Solar radiation; Tulip bulb; Ultraviolet; Underground city; vernalization;

  • We need to learn more about wisdom and invention of botany as the predecessor of life.
  • 我々は生命の先輩としての植物の知恵と工夫についてもっと学ぶ必要がある。

>Top 0. Introduction:

  • Talks about plants appear our everyday life.
  • Plants look like to feel various senses and reconize the change of enviroment or season. They cannot move, but they do everything to survive on the earth.

0. 序:

  • 植物の話題は尽きない。
  • 植物にも環境を感知することができるらしい。

>Top 1. What food do plants eat?:

  • What food does the plant eat?
    • Aristotle (384-322BC) once said the botany is an headstand animal; its roots eat something underground, with having its genitals in the upper part.
    • Jan Baptista van Helmont (1579-1644) of Flanders calculated the weight of soil and a planted willow; discovering almost no change of weight of soil though the willow grew 30 times weigh.; this experiment showed the willow grew only absorbing water from its root.
    • Ancient idea considered the functions of leaves as well as flowers, or even fruits are only kinds of decoration; which freshen up or remodel those colors and shapes according to the seasons.
      • But some people might recognized the leaves turn those directions to the sun (heliotropism).
    • Julius von Sachs (1832-97), German botanist, developed the concept of photosynthesis, finding chloroplast in the leaf; which after being in sunlight, then bleached white and stained with iodine turns black, showing starch was produced by carbon dioxide; whereas the same leaf out of the sun remained white.
      • The botany lives using clean energy; sunlight, water and carbon dioxide, on the chloroplast in the leaf.
      • Leaves function as an factory of foods for creatures; even the animal finally depends its food on the plant.
      • The plant uses only 0.12% of solar energy; but humans could not succeed in synthesizing glucose or starch using solar energy.
    • CO2 concentration in the atmosphere: around 370 ppm (0.037%)
      • The concentration drops in summer, and rises in winter in north hemisphere.
      • How the plant absorb such sparse gas as CO2 through stomata.
      • The leaf uses diffusion by concentration gradient (Fick's law) to absorb CO2.
  • >Top Light: Why the leaf is green?:
    • blue or red spectrum are absorbed by the leaf, but green spectrum penetrates.; the color seen from backside of the leaf is green, while the green color reflects at the front side of the leaf.
      • The leaf can feel not only the strength of light, but the kind of it.
      • Far infrared radiation penetrate the leaf more than green, but we could not recognize it.
      • The leaf illuminated by blue or red light looks black (because it is absorbed) when we look it from backside.
      • Light is indispensable (almost 70% of seeds) to germinate. The seed can feel the sunlight.
  • >Top What color is used in photosynthesis?
    • The plant uses all colors of light effectively; positive chlorophyll located in the front side of a leaf absorbs blue and red color light, while negative chlorophyll in the back side absorbs green color light.
    • This mechanism was succeeded from the age of green algae, which is the root of the plant.
    • Far-red spectrum light is neither used in photosynthesis, nor germination; ultra-red right penetrates most of leaves; such lower places covered by many leaves are not preferable place to live.
      • Phytochrome is a photoreceptor of a plant; there are two types of photoreceptor; sensitive receptor (Pr-type) of red spectrum and (Pfr-type) of far-red spectrum.
  • >Top Solar radiation: (>Fig.)
    • Human beings can recognizing longer spectrum as a red light, whose upper limit is around 760-830nm; above which is called infrared light.
      • Infrared (IR) is segmented, Near-infrared (NIR, 075-1.4μm), Short-wavelength infrared.
      • Infrared atmospheric window: between 8 and 14μm. A fragmented part of the windows spectrum can also be seen between 0.2 and 5.5μm.
  • >Top Light Response: (>Fig.)
    • Light wavelength is roughly divided in blue (400-500nm), green (500-600nm), red (600-700nm), and far-red (700-800mn) spectrum.
    • The function of pigment of a leaf called photochrome affects; 1) seed germination, 2) bud differentiation, 3) anthesis, 4) cotyledon development, 5) chlorophyll synthesis, 6) internode elongation, etc.
    • Effectiveness of photosynthesis is in the order of 1) Red, 2) Blue, 3) Green, but Far-red spectrum has effect neither in photosynthesis, nor germination.
  • >Top Emission Spectrum: Florescent Lamp Factory: (>Fig.)
    • Such factory had used specially designed florescent lamp similar to the sunlight spectrum.
    • Now LED lamps and/or LD (semiconductor laser) are used, having strong in tensity in blue (450nm) and red (660nm) spectrum for efficient absorption by energy.
    • Luminous sensitivity by humans and effective absorption for photosynthesis are different: Eg. Blue LED of 450nm has only 0.038 luminous sensitivity, i.e., only 4% of light is sensitive to humans. (W/sq.m=lx)
  • Bean sprout out:
    • Strange shape: a fish hook, pushing out surrounding soil to extend.
    • Bud or sprout with two cotyledons has preferable shape in developing underground.
    • Bean sprout cannot make chlorophyll for photosyntheses, which is useless underground.

1. 何を食べているのか:

  • heliotropism: 向日性 Cf. photoaxis
  • stama, -mata: 気孔
  • chloroplast: 葉緑体
  • germinate: 発芽する
  • phytochrome: 光受容体
  • light response: 光反応
  • photomorphogenesis: 光形態形成 <photomorphology 光形態
  • seed germination: 種子発芽
  • bud differentiation: 花芽分化
  • anthesis: 開花
  • cotyledon development: 子葉展開
  • chlorophill systhesis: 葉緑素合成
  • internode elongation: 節間伸張
  • light source: 光源
  • luminous senitivity: 光感度
  • >Top 葉緑素 C55H70O6N4Mg (Chlorophyll-b)
  • 植物はなぜ緑色なのか?
  • Chlorophyll-a: X=CH3,
    Chlorophyll-b: X=CHO
  • chlorophyll
  • 光合成で利用される光:
  • Solar raditaion: 太陽放射と大気の窓:


  • Light response: 光反応


  • Emission Spectrum: 発光スペクトル







  • もやし


>Top 2. How do plants struggle with stress?:

  • Stress felt by the plant:
    • "Hyponica" tomato: a kind of hydroponics; a tree of tomato can bear fruits as much as 12,000 without using soil.
    • The plants such as tomato, melon, or cucumber feel some kind of stress in cultivating in normal greenhouse or in open field cultivation; such stress is caused by different strength of light, temperature, humidity, pollution in the air, bacteria, harmful insects, and surrounding grass, as well as various agricultural chemical.
    • How to pump up water from roots to stomas of leaves: by the way of pushing up and pulling up water through plant conduit.
    • Trees grow upward from the tip of truck and branches, as well as grow thick from the outermost of trunk.
    • Water vapor in the atmosphere is evaporated from 1) the surface of seas, lakes, rivers (88%) and 2) the surface of land (12%); about 96% of the 2) is from evaporation from plants: the evaporation from leaves correspond to sweating of animals, adjusting temperature of the plant body. Nutrients are also transported in the form of dissolved water.
    • Roots are like capillary vessels, which extend more than 100 times of above ground parts.
      • A human is said having the length of 90,00 km of vessels including capillary ¥ to supply oxygen to each cell in a body.
      • The place whose seed germinate determines the destiny of the plant.
      • The seed coat, or episperm adjusts the timing of germination; the seed coat is softened by bacteria, then recognizes there is enough surrounding water.
      • A plant consumes 500-800 gram water to grow 1 gram of its dry weight by photosynthesis: this means only net 1 gram of water is effectively used as a material for the photosynthesis.
    • Moisture is the key for a plant to grow; leaves which open stomata to absorb CO2 lose water much by evaporation. Keeping high humidity in nighttime is necessary for the plant to consume for photosyntheses in the daytime.
      • Crassulacean Acid Metabolism (CAM); some plants evolved to adapt in arid condition. The stomata of CAM plant remain shut in the daytime to reduce evaporation, but open during in the nighttime to collect CO2. (Eg. cactus, pineapple, aloe.)
    • >Top Photoperiodism: physiological response of creatures to period of day or night by internal body clock.

2. ストレスと闘う:

  • gymnosperm: 裸子植物
  • angiosperm: 被子植物; dicotyledons & monocotyledon
  • nutrient: 養分
  • mid-summer drainage; or intermittent irrigation: 中干し
  • episperm; seed coat: 種皮
  • ハイポニカ・トマト水栽培

>Top <Underground Future City>

  • Modern city paved by the concrete caused 'heat island' phenomenon; against which making a small garden on the roof of the building is getting popular to save the energy.
  • What about to return almost all the surface to the plant; making much more fields or rice paddies in the city, and making underground living area for human being.
  • The energy is generated by sunlight or wind on the surface, and people move by metro.
  • It is comfortable to walk or play on the spacious garden on the surface, or to drive by EV along the road covered by forest; and sweating together with the plants.
  • CAM植物:
    CAM: ベンケイソウ型有機酸代謝

>Top 3. How do plants defend their bodies?

  • Ultraviolet: wavelength (10-400nm), shorter than visible light ( 400-700nm) and longer than X-rays.
    • Ultraviolet light is hazardous to the life, which could not land until the ozone layer was created. The life started photosynthesis in the sea, gradually accumulating oxygen in the environment.
    • The ozone layer can absorb ultraviolet light, particularly the most hazardous UV-C; thereafter the life could expand its living area in the land.
    • The life was born around 4B years ago, spending 3.6B years in the sea; then
      the plant landed just 400M years ago, ahead of animals.
    • When the life is exposed to ultraviolet light, active oxygen arises and accelerate aging process or causing skin cancer, or cataract; thus we need to avoid being exposed to ultraviolet light as much as possible.
  • >Top Beautiful color of flowers:
    • The plant can product antioxidant such as Vitamin-E, Vitamin-C, carotene, anthocyanin, or lycopene. Carotene is the color of carrot, anthocyanin is of egg plant, apple, or blue berry, and lycopene is of tomato or water melon.
    • Strong ultraviolet radiation causes plants to protect themselves by having bright color of flowers; or beautiful color of flowers is the sign of struggling against ultraviolet light.
  • >Top phosphoenolpyruvic acid (PEP):
    • C4 plants have this PEP, which enable to survived low density of CO2.; such plants as corn, sugar cane, or green foxtail.; consume 250-350 g of water to increase 1 dry gram growth of body.
    • C3 plants (share 90% of plants) have no such PEP, can utilize 1/3 of sunlight energy; consume 500-800 g of water to increase 1 dry gram growth of body.
    • On the earth, only 25% of land areas have more than 1,000 mm annual rainfall, 55% of land have less than 500 mm (half of which have only less than 250 mm)
      • The severe factors for plants are intense sunlight, high temperature, aridity.
      • Such C4 plants are better suited in lower latitude areas featured with intense sunlight, high temperature and aridity.
      • Under the intense sunlight, C3 plants use 1/3 for photosynthesis, and the rest 2/3 is used to make active oxygen which is harmful; C3 plant has the mechanism to dissolve such active oxygen, consuming excess energy, and producing additional CO2.
  • >Top Regenerative ability of plants:
    • Plant a cutting is possible.
      • Plant does not care about losing a part of its body; yielding regenerate or even increase its number.
    • Far-red light make a plant to grow taller; the ratio of far-red light indicates that surrounding plants are growing taller, which promotes the plant to grow taller more rapidly to gain more sunlight.
      • In a same colony of plants, the inner plants tend to grow taller than the surrounding ones.
      • Some kinds of plants (such as walnut, artemisia, helianthus, or cherry tree) distribute poisonous materials to curb the germination or growth of different plants.
      • Or some plants retains poisonous materials (such as nicotine, atropine, or digitoxin) in its body.
        • Some animals have counter-strategies: some animals eat particular food only such as silkworm eats mulberry leaves only, panda eats bamboo grass, and koala eats eucalyptus leaves.
  • >Top Five senses of plants:
    • These are seeing, hearing, smelling, tasting, and touching senses:
    • Seeing:
      • Seeds knows not only the place where it exists but surrounding situation how it is preferable to germinate.
    • Hearing:
      • There is an opinion that tomato tree grows more sweet tomato fruits when heard classic music than rock or pop music, which is not yet confirmed.
    • Tasting:
      • When floating grass is dipped in salty water (3% of salt) for 10 minutes, then float in the normal water for 2 hours; some special material is emitted from the grass. This mysterious material is imagined to be able to hasten blooming and increase the number of flowers.
    • Touching:
      • Bean sprout gains some incentive by touching soils, making its stem thicker and shorter.
    • Feeling:
      • Any plant can feel gravity; extending its stem upward and its root downward; even if it is lain alongside, its root begins to bend downward, and its step opposite.
    • >Top Smelling:
      • Plants have various strategies to counter invasion of pathogen such as fungus, bacteria, or virus; by coating wax on its surface or by enclosing pathogen by killing the invaded cells by themselves, emitting phytoalexin, antibacterial agent, in ten and several hours.
      • SOS signals: infected leaves emit salicylic acid which evaporates immediately and transmit information of the infection to the same group of plants.

3. 体を守る:

  • cataract: 白内障
  • antioxidant: 抗酸化物質
  • phosphoenolpyruvic acid (PEP): ホスホエノールビルビン酸
  • Regenerative ability: 再生能力
  • plant a cutting: 挿し木
  • artemisia: ヨモギ
  • helianthus: ヒマワリ
  • pathogen: 病原体
  • phytoalexin: <G. phyto, plant
  • 花の鮮やかさは紫外線を防ぐ色

< Ultraviolet:>ultraviolet

    • Ultraviolet-A (UVA): 315-400 nm; not absorbed by the ozone layer.
    • Ultraviolet-B (UVB): 280-315; mostly absorbed by the ozon layer.
    • Ultraviolet-C (UVC): 100-280; germicidal, completely absorbed by the ozone layer.
    • Vauum ultraviolet (VUV): 10-200
    • Extreme ultraviolet (EUV): 10-121
  • <Electromagnetic Spectrum>


  • C4植物とC3植物
    • C4植物は、低濃度CO2をよく吸収できる植物。最初に体内で生成するCの数が4個。
    • C3植物は地球上の90%以上。C3個を最初に生成。
  • 植物にとっての厳しい3条件:



  • 植物に五感はあるか:
    • 視覚:
    • 聴覚:
    • 味覚:
    • 触覚:
    • 嗅覚:

>Top 4. How do plants anticipate seasons?

  • Why do most of plants bloom in either spring or autumn?
    • Plants need to prepare too hot summer and too cold winter, anticipating the approach of summer and winter.
      • Animals can move or migrate to avoid too hot or too cold seasons.
    • Leaves feel change of seasons by measuring length of night; the longest night is at summer solstice, and the shortest at winter solstice.
    • After the solstice the actual hottest or coldest season begins 1-2 months later.
  • >Top Secret material: florigen (blooming hormone)
    • When leaves feel substantial length of night duration, they emit blooming message called 'florigen' to each bud to prepare blooming.
    • Humans try to identify this florigen to control the timing of blooming, but which has not yet successful. (called 'illusory florigen')
  • >Top Life of leaves:
    • Leaves recognize change of season, being prepared to fall down when autumn comes.
    • Absciss layer, the separation part is made near the stalk before falling down of the leaf.
    • Falling leaves almost remain neither protein nor starch; which should be returned to the stem side in the form of amino acid and glucose.
    • Symptoms of aging of old leaves have started after new leaves develop. Old leaves can make no more photosynthesis, whose products as protein and starch are returned to the stem for reuse.
    • >Top Longer night makes leaves emit abscisic acid, and the overwinter bud is made to prepare for winter season.
      • Why buds are made in summer season which will bloom in the next year spring, not in the following autumn. (though the temperature of autumn and spring is almost same.)
      • Trees blooming in spring like plum, cherry or peach need more time from blooming till bearing fruits; thus they make overwintering buds, which are scheduled to bloom after feeling coldness of winter.
      • Plum blooms earlier than cherry or peach, because buds of plum can grow in lower temperature than cherry or peach.
      • There are two types of overwinter bud; 1) overwinter bud contains leaves wrapping bud, or 2) overwinter bud wrapping leaves; 1) is plum, peach, magnolia, and cherry (someiyoshino - Prunus yedoensis), which bloom before coming out of leaves, and 2) is wild cherry blossoms (yamazakura) or hydrangea, which bloom after leaves.
  • >Top Photoperiodicity:
    • Leaves of potato or sweet potato also recognize length of night; after recognizing longer night potato or sweet potato begin to gain weight. If mercury lamp is lit during night, these potato or sweet potato cannot grow well due to less amount of product by photosynthesis.
    • Long-day condition or short-day condition: in addition 'light interruption' lit for short time (30 minutes) may confuse long-night condition (Eg. 16 hours).
  • >Top Bulb of flowers:
    • Bulbs (of tulip, crocus, hyacinth, or daffodil) are made (underground) during summer time; similarly trees blooming in spring make bud in summer time.
      • Why tulip does not bloom in autumn? The bud (or bulb) needs lower temperature (8-9ºC) to develop pistil, stamen, and petal; and in the next spring it blooms according to the rise of temperature.
      • Bulb put in the refrigerator for a certain period may mistake to fee the arrival of winter, then it begin to bloom earlier.
    • The tulip bulb caused bubble economy in 17C (around 1637) in the Netherland.
    • Cluster-amaryllis: triploid (not diploid), having no seeds, blooms in autumn.
    • Vernalization: cooling of seed during germination to accelerate flowering when it is planted.
      • Autumn sowing wheat; need to be pressed down into frost by foot to feel coldness of winter; which is need to make bud in the next spring.

4. 季節を先取りする:

  • florigen: 開花ホルモン物質
  • absciss layer: 離層
  • overwinter bud: 越冬芽
  • photoperiodity: 光周性
  • vernalization: 春化
  • 開花ホルモン:
    • フローリゲン



  • 葉の寿命:
    • 離層の形成
    • 葉は積極的に落葉の準備をする
    • 越冬芽
    • 春化







  • 光周性:
    • 長日条件
    • 短日条件



  • 球根
    • チューリップ球根
    • 春開花するための工夫
    • 春化



>Top 5. How do plants manage reproduction?:

  • In 2000 StarLink incident: pollen of US Genetically Modified Organisms (GMO) contaminated ordinary corn, etc.
    • Pollinosis:
      • Size of pollen: 30-100μm; being transported by wind, insects, or birds.
      • 2-100 stamina (against 1 pistil) to scatter many pollens as long as several hundred or more km distant.
      • 17M pollinosis patients in Japan.
    • Flower garden is the battle field for the plants to survive.
      • Dioecious plants: ginkgo, zanthoxylum, kiwi fruit, asparagus or spinach
      • Dichogamy; ripening of stamens and pistils of a flower at different times, so that self-fertilization is prevented.
      • Self-incompatible: unable to be fertilized by its own pollen to prevent inbreeding; like pear or apple tree.
  • >Top Various technologies of improving plants:
    • Tissue culture: growth in an artificial medium of cells derived from living tissue.
      • orchid, cherry, or alpine plants are increased by this totipotent technology.
    • grafting: a shoot or twig inserted into a slit on the trunk or stem of a living plant.
      • delicious Asian pear (20C pear): is self-incompatible, increased worldwide by grafting from a tree accidentally discovered in garbage dump in 1904.
      • Prunus yedoensis (someiyoshino cherry) is self-incompatible tree, also increased worldwide by grafting.
    • heterosis: relating to hybrid vigor, having better features than their parent.
      • cruciferous plants: radish, cabbage, Chinese cabbage, broccoli are all self-incompatible.
      • hybrid rice: making heterosis using a kind of rice which cannot make stamens.

5. 生殖に工夫を凝らす:

  • pollen: 花粉
  • pistil: 雌蕊
  • stamen, stamina: 雄蕊
  • pollinosis: 花粉症
  • dioecious: 雌雄異花
  • dichogamy: 雌雄異熟
  • self-incompatible: 自家不和合性
  • tissue culture: 組織培養
  • totipotency: 分化全能性
  • grafting: 接ぎ木
  • heterosis: 雑種強勢
  • cruciferous: アブラナ科 (十字花弁)
  • 接ぎ木
  • 花粉症
  • 雌雄異花
  • 雌雄異熟
  • There are versatile terminology related biology or botany, which proved that biology (agriculture) and language have developed together hand in hand.
  • Understanding about the sun probably began from understanding blessing of the sunlight, just as heliotropic plants.
  • Blooming concurrently at the same timing is to distribute and be accepted the pollens effectively.
  • 生物や植物に関する豊かな用語がある。これは生物学と言語とが手を携えて発展してきたことの証左でもある。
  • 太陽に関する理解は、向日性植物のように、太陽光の恵みを理解することから始まったのだろうと思う。

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