Sexual Reproduction in Flowering Plants

Corn develops a fibrous root system, which spreads horizontally through the soil, while beans grow a taproot system, with a single main root that anchors the plant.

This stage is crucial because plants begin producing food through photosynthesis, which supports further development and allows them to grow taller and produce flowers and fruits.

Beans are self-pollinated, meaning they can fertilize themselves, while corn requires wind pollination, which transfers pollen from the male tassel to the female silk.

<p>In beans, fertilized flowers develop into pods that contain seeds. Pods mature, dry out, and release the seeds. In corn, each fertilized silk strand becomes a kernel, which fills with starch as it matures. The entire plant eventually dries out, indicating the kernels are ready to be harvested.</p> Signup and view all the answers

<p>The coleoptile protects the emerging shoot tip and allows it to break through the soil. Once the coleoptile is freed, it splits and the first leaves of the corn plant can begin photosynthesis.</p> Signup and view all the answers

<p>The three main conditions necessary for seed germination are water (moisture), oxygen, and suitable temperature.</p> Signup and view all the answers

<p>The cotyledons in bean plants provide nutrients for initial growth before they wither as true leaves develop.</p> Signup and view all the answers

<p>Epigeal germination is when the cotyledons are pushed above the soil, as seen in bean plants. Hypogeal germination is when the cotyledons remain below the soil, like in corn plants.</p> Signup and view all the answers

<p>Oxygen is crucial for aerobic respiration, which provides the energy needed for cell division and growth in the germinating seed.</p> Signup and view all the answers

<p>Different plant species have specific temperature ranges for germination because temperature influences enzyme activity, which is essential for breaking down stored food and initiating growth. Warm-season crops like maize require higher temperatures, while cool-season crops like beans germinate at lower temperatures.</p> Signup and view all the answers

<p>The cotyledons provide the food source or store for the seed until the plant grows leaves.</p> Signup and view all the answers

<p>The coleoptile is a protective sheath that covers the plumule in corn plants during germination. It helps push the plumule through the soil until it reaches light.</p> Signup and view all the answers

<p>Seed dispersal reduces competition for resources like light, water, and nutrients between the parent plant and its offspring.</p> Signup and view all the answers

<p>Even if all three conditions are met, a seed may fail to germinate due to factors such as seed age, dormancy, or damage to the embryo.</p> Signup and view all the answers

<p>An annual plant completes its life cycle in one growing season, meaning it germinates, grows, flowers, produces seeds, and then dies. Examples include bean plants and corn plants.</p> Signup and view all the answers

<p>Wind dispersal utilizes lightweight seeds with wings or feathery structures, like dandelion seeds. Water dispersal relies on seeds with air pockets, allowing them to float, such as coconuts.</p> Signup and view all the answers

<p>Water, Oxygen, and Suitable Temperature.</p> Signup and view all the answers

<p>The seed absorbs water, causing it to swell.</p> Signup and view all the answers

<p>The radicle grows downwards to form roots, anchoring the plant and absorbing water and nutrients from the soil.</p> Signup and view all the answers

<p>The plumule grows upwards to form the shoot, giving rise to leaves and enabling the plant to perform photosynthesis.</p> Signup and view all the answers

<p>The plant will likely be around 45-50 cm tall after 8 weeks, based on the trend of steady growth observed in the graph. The growth rate seems to be approximately 10 cm per week, so extending the line of best fit suggests a height between 45-50 cm for Week 8.</p> Signup and view all the answers

<p>The two main types of pollination are self-pollination, where pollen is transferred within the same flower, and cross-pollination, where pollen is transferred between different flowers. Cross-pollination offers advantages like increased genetic diversity and potential for better adaptation to changing environments.</p> Signup and view all the answers

<p>Following fertilization, the zygote undergoes cell division and differentiation to form an embryo. The ovule, which contained the egg cell, transforms into a seed. The outer layers of the ovule develop into the seed coat, protecting the embryo.</p> Signup and view all the answers

<p>A seed comprises the embryo, cotyledons (seed leaves), and often an endosperm. The embryo, containing the plumule (future shoot) and radicle (future root), represents the young plant. Cotyledons store food for the developing embryo. The endosperm, present in some seeds, provides additional food storage.</p> Signup and view all the answers

<p>Seed dormancy is a state where a mature seed remains inactive, delaying germination until conditions like adequate moisture, temperature, and light are favorable. This mechanism ensures successful germination when environmental conditions are optimal for plant growth.</p> Signup and view all the answers

<p>After fertilization, the ovary of the flower enlarges and develops into a fruit. The ovary wall thickens, forming the pericarp, which protects the developing seeds.</p> Signup and view all the answers

<p>True fruits develop solely from the ovary of the flower (e.g., mango, tomato). False fruits, on the other hand, develop from other parts of the flower, such as the receptacle (e.g., apple) or the floral tube (e.g., cashew), in addition to the ovary.</p> Signup and view all the answers

<p>Fruits play crucial roles in protecting seeds from damage and drying out, ensuring their survival. Additionally, they facilitate seed dispersal through various mechanisms, like wind, water, or animals, enabling the plant species to spread and colonize new territories.</p> Signup and view all the answers

<p>The testa is the protective outer layer of a seed, also known as the seed coat. It is formed from the outer layers of the ovule and plays a vital role in safeguarding the seed from environmental damage, pathogens, and desiccation.</p> Signup and view all the answers

The protective sheath covering the emerging shoot of a seedling, allowing the first leaves to appear.

A phase where plants develop leaves and roots, enhancing their ability to absorb water and nutrients.

The process where a plant fertilizes itself, often seen in beans during flowering.

A method of pollination where wind carries pollen from male to female flowers, common in corn.

The process in corn where fertilized silk strands develop into kernels filled with starch.

The fusion of gametes leading to seeds and fruits.

Includes petals, sepals, stamen, and pistil.

Transfer of pollen from anther to stigma.

Pollen transfer between different flowers.

Zygote becomes embryo; ovule transforms into a seed.

Develop only from the ovary after fertilization.

Seeds remain inactive until conditions favor germination.

Seed leaves which store food for the embryo.

The young shoot that develops into the future stem of the plant.

The young root that emerges first from the seed.

The process of spreading seeds away from the parent plant to reduce competition.

Seeds that are lightweight and travel on the wind (e.g., dandelion).

Seeds eaten and excreted by animals, or seeds that attach to fur.

Requirements such as water, oxygen, and temperature for seeds to sprout.

Processes seeds go through: water absorption, enzyme activation, root, and shoot emergence.

Three key factors are water, oxygen, and suitable temperature.

Water softens the seed coat and activates enzymes for growth.

Oxygen is needed for aerobic respiration for energy.

Temperature affects enzyme activity; different seeds need different ranges.

In beans (dicots), cotyledons rise above soil as the hypocotyl elongates.

In corn (monocots), the cotyledon stays buried while the coleoptile emerges first.

Cotyledons supply nutrients until true leaves develop.

Annual plants grow, flower, and produce seeds in one season.