📚 GCSE CIE Science: Plant Biology Key Points | GCSE CIE 科学：植物 考点精讲
Plant biology is a core topic in the CIE Coordinated Sciences (Double Award) and Biology syllabus. Understanding plant structure, transport, photosynthesis, reproduction, and responses is essential for tackling both multiple-choice and structured questions. This article breaks down the key points in a clear, bilingual format.
植物生物学是 CIE 综合科学（双奖）及生物学课程的核心主题。理解植物的结构、运输、光合作用、生殖和反应，对于应对选择题和结构化问题至关重要。本文以中英对照形式梳理核心考点。
1. Plant Cells and Tissues | 植物细胞与组织
Plant cells have unique structures: a cellulose cell wall, a large permanent vacuole, and chloroplasts in photosynthetic tissues. The vacuole contains cell sap and helps maintain turgor pressure, which supports the cell and plant.
植物细胞有独特结构：纤维素的细胞壁、大型永久液泡，以及光合组织中的叶绿体。液泡内含细胞液，有助于维持膨压，支撑细胞和植株。
Key tissues include palisade mesophyll (packed with chloroplasts for photosynthesis), spongy mesophyll (gas exchange), xylem (water and mineral transport), and phloem (translocation of sugars). Epidermal tissues cover outer surfaces for protection and often have a waxy cuticle.
关键组织包括栅栏叶肉（充满叶绿体，用于光合作用）、海绵叶肉（气体交换）、木质部（水和矿物质运输）和韧皮部（糖类转运）。表皮组织覆盖外部起保护作用，常具蜡质角质层。
2. Photosynthesis | 光合作用
Photosynthesis is the process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen. The overall word equation is: carbon dioxide + water → glucose + oxygen, in the presence of chlorophyll and light.
光合作用是植物利用光能，将二氧化碳和水转化为葡萄糖和氧气的过程。总反应文字方程式为：二氧化碳 + 水 → 葡萄糖 + 氧气，需要叶绿素和光照。
The balanced chemical equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Factors affecting the rate include light intensity, carbon dioxide concentration, and temperature. At low light intensity, rate is limited by light; as CO₂ levels rise, the rate increases until another factor becomes limiting.
平衡化学方程式为：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂。影响光合作用速率的因素有光照强度、二氧化碳浓度和温度。光照较弱时，速率受光照限制；随着二氧化碳浓度升高，速率增加，直到另一因素成为限制因子。
3. Mineral Nutrition and Deficiencies | 矿质营养与缺乏症
Plants need nitrate ions for making amino acids and proteins. A nitrate deficiency causes stunted growth and yellow older leaves because nitrogen is mobile and moves to younger tissues.
植物需要硝酸根离子合成氨基酸和蛋白质。缺氮会导致生长矮小、老叶发黄，因为氮是可移动元素，会转移至新组织。
Magnesium ions are required for chlorophyll synthesis. Magnesium deficiency leads to chlorosis, where leaves turn yellow between veins while veins remain green. Insufficient magnesium reduces photosynthesis efficiency.
镁离子是叶绿素合成所必需的。缺镁会导致萎黄病，叶片叶脉间变黄，而叶脉保持绿色。镁不足会降低光合作用效率。
4. Transport in Plants: Xylem and Phloem | 植物运输：木质部和韧皮部
Xylem vessels are dead, hollow tubes strengthened with lignin. They transport water and dissolved mineral ions from roots to the leaves in a unidirectional flow. Water moves via transpiration pull, cohesion, and adhesion.
木质部导管是死细胞形成的中空管道，由木质素强化。它们从根部向上单向运输水分和溶解的矿物质离子。水分通过蒸腾拉力、内聚力和附着力共同移动。
Phloem consists of living sieve tube elements and companion cells. Phloem translocates sucrose and amino acids from sources (e.g., leaves) to sinks (e.g., roots, fruits) in both directions. This requires energy from respiration.
韧皮部由活细胞筛管分子和伴胞组成。韧皮部将蔗糖和氨基酸从源（如叶片）向库（如根、果实）双向转运。这一过程需要呼吸作用提供能量。
5. Transpiration and Factors Affecting It | 蒸腾作用及其影响因素
Transpiration is the evaporation of water from mesophyll cell surfaces, followed by diffusion of water vapour out through stomata. It creates a water potential gradient that drives water uptake and transport.
蒸腾作用是水分从叶肉细胞表面蒸发，然后水蒸气通过气孔扩散出去的过程。它产生水势梯度，驱动水分的吸收和运输。
Factors increasing transpiration rate: higher temperature (increases kinetic energy of water molecules), lower humidity (steeper concentration gradient), greater air movement (removes humid air), and higher light intensity (stomata open wider). A potometer can be used to measure water uptake as an estimate of transpiration rate.
增加蒸腾速率的因素：较高温度（增加水分子动能）、较低湿度（更陡的浓度梯度）、较强空气流动（带走潮湿空气）和较高光照强度（气孔开得更大）。可用蒸腾计测量吸水量来估算蒸腾速率。
6. Structure of a Flower | 花的结构
A typical insect-pollinated flower contains the male stamens (anther and filament) and the female carpel (stigma, style, and ovary). Petals are often brightly coloured to attract pollinators, and sepals protect the bud.
典型的虫媒花包含雄性雄蕊（花药和花丝）和雌性心皮（柱头、花柱和子房）。花瓣常色彩鲜艳以吸引传粉者，萼片保护花蕾。
The anther produces pollen grains containing male gametes. The stigma is sticky to receive pollen. The ovary contains ovules, each with a female gamete. After fertilisation, the ovule becomes a seed and the ovary wall develops into the fruit.
花药产生含有雄配子的花粉粒。柱头黏性以接收花粉。子房内有胚珠，每个胚珠含一个雌配子。受精后，胚珠发育成种子，子房壁发育成果实。
7. Pollination and Fertilisation | 传粉与受精
Pollination is the transfer of pollen from an anther to a stigma. Self-pollination occurs within the same flower or plant, while cross-pollination involves different plants of the same species, increasing genetic variation.
传粉是花粉从花药传到柱头的过程。自花传粉发生在同一朵花或同一植株内，而异花传粉则涉及同种不同植株，能增加遗传变异。
After pollination, a pollen tube grows down the style carrying the male nucleus. Fertilisation is the fusion of the male nucleus with the egg cell inside the ovule to form a zygote. Another male nucleus fuses with polar nuclei to form endosperm, which provides nutrition for the embryo.
传粉后，花粉管沿花柱生长，携带雄核。受精是雄核与胚珠内的卵细胞融合形成合子。另一个雄核与极核融合形成胚乳，为胚提供营养。
8. Seed and Fruit Development | 种子与果实发育
The fertilised ovule becomes a seed. The seed contains an embryo (plumule, radicle) and a food store (cotyledons or endosperm), surrounded by a protective seed coat (testa). The ovary wall develops into the fruit, which aids in seed dispersal.
受精的胚珠成为种子。种子内含胚（胚芽、胚根）和营养储存（子叶或胚乳），外包保护性种皮（外种皮）。子房壁发育成果实，有助于种子传播。
Fruits can be dry dehiscent (split open, e.g., pea pod), dry indehiscent (do not split, e.g., sunflower), or fleshy (e.g., apple). Dispersal mechanisms include wind, water, animals, and explosive self-dispersal, reducing competition with the parent plant.
果实可以是干开裂（如豌豆荚）、干闭果（如向日葵）或肉果（如苹果）。传播机制有风力、水力、动物和自身弹射，以减少与母本植株的竞争。
9. Germination and Conditions Required | 萌发与所需条件
Germination is the resumption of growth in a seed. Essential conditions are water (to activate enzymes and transport soluble food), oxygen (for aerobic respiration), and a suitable temperature (for optimal enzyme activity).
萌发是种子恢复生长的过程。必需的条件有水（激活酶并运输可溶性养分）、氧气（用于有氧呼吸）和适宜温度（保证酶最佳活性）。
Initially, the seed absorbs water and swells, the testa ruptures, and the radicle emerges first to anchor the plant and absorb water. The plumule then grows upward. Energy comes from the food store via respiration until the seedling can photosynthesise.
种子先吸水膨胀，种皮破裂，胚根首先伸出以固定植株并吸收水分。然后胚芽向上生长。能量来自呼吸作用分解储存养分，直至幼苗能进行光合作用。
10. Plant Hormones and Tropisms | 植物激素与向性
Auxin is a plant hormone produced in shoot tips that regulates growth. In phototropism, auxin moves to the shaded side of a shoot, causing cells there to elongate more, so the shoot bends towards light. This is a positive phototropic response.
生长素是一种在茎尖产生的植物激素，调节生长。在向光性中，生长素移动到茎的背光侧，促使该侧细胞伸长更多，结果茎向光弯曲。这是正向光性反应。
In gravitropism (geotropism), roots grow downward (positive gravitropism). Auxin accumulates on the lower side of a root placed horizontally, but in roots high auxin concentration inhibits growth, so the upper side elongates more and the root bends downward.
在向地性中，根向下生长（正向地性）。将根水平放置时，生长素积聚在根的下侧，但在根中高浓度生长素抑制生长，所以上侧伸长更多，根向下弯曲。
11. Asexual Reproduction in Plants | 植物的无性繁殖
Asexual reproduction produces genetically identical offspring (clones) without gametes. Natural methods include runners (strawberry), bulbs (onion), and tubers (potato). These allow rapid colonisation of a favourable habitat.
无性繁殖无需配子，产生遗传相同的后代（克隆）。天然方式有匍匐茎（草莓）、鳞茎（洋葱）和块茎（马铃薯），能快速占据适宜生境。
Artificial methods include cuttings and tissue culture (micropropagation). Cuttings are treated with rooting powder containing auxin to promote root formation. Micropropagation uses small explants grown on sterile nutrient agar under controlled conditions to produce large numbers of disease-free plants.
人工方法有扦插和组织培养（微繁殖）。插条用含生长素的生根粉处理以促进生根。微繁殖利用小外植体在无菌营养琼脂上培养，在受控条件下大量生产无病植株。
12. Plant Defences and Adaptations | 植物防御与适应
Plants have physical defences like thorns, spines, hairs, and tough bark. Chemical defences include production of toxins (e.g., cyanide in foxgloves), bitter alkaloids (e.g., in tobacco), and sticky resins. Some plants produce insect-repelling scents.
植物有物理防御，如刺、棘、毛和坚硬的树皮。化学防御包括产生毒素（如毛地黄中的氰苷）、苦味生物碱（如烟草）和黏性树脂。有些植物释放驱虫气味。
Xerophytes (e.g., cacti) are adapted to dry conditions with thick waxy cuticles, sunken stomata, rolled leaves, and reduced leaf area. Hydrophytes (e.g., water lilies) have large air spaces (aerenchyma) for buoyancy and stomata on upper surfaces.
旱生植物（如仙人掌）适应干燥环境，具有厚的蜡质角质层、下陷气孔、卷曲叶片和缩小叶面积。水生植物（如睡莲）有大型气室（通气组织）以助浮力，气孔位于上表面。
Published by TutorHao | GCSE CIE Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导