Plants, like people, undergo their own life cycle. Beginning as seeds containing everything needed for them to blossom into full-grown plants, the seeds are dispersed across the land by water, air or animals (except ferns and bryophytes ). When seeds reach soil with sufficient essential elements they undergo germination and begin growing into fully formed plants.
Seeds
No matter where they’re planted – be it in the ground or a jar on your windowsill – seeds require three components in order to begin sprouting: water, light and heat. With these three conditions present, seeds can crack their hard seed coat and release an embryo within. When this happens, its energy begins flowing into a process known as starchy material digested by this embryo which feeds energy back into growing into plants – sprouting can last from days or even weeks depending on your growing conditions.
Once a seedling has become established, its roots begin growing down into the soil to absorb water and nutrients, while a green shoot grows upward towards sunlight. At this stage of its lifecycle, photosynthesis kicks in to make the food itself. Carbon dioxide from air meets sunlight energy to create glucose which stores this energy for future use by the plant in its growth phase.
Once a plant has set its seeds, it begins producing flowers to attract bees and other pollinating insects for pollination. If these pollinations efforts succeed, ripened fruit containing its seeds are dispersed via wind, water, animals or wind through windmills; whereby wind, water or animal transport then disperse these seeds to other locations where they germinate and repeat this life cycle again. Decomposing plant material decays in soil too releasing nutrients back into ecosystem and providing food sources such as earthworms or fungi which help recycle or reuse its natural resources in this way.
Germination
A plant’s lifecycle begins when a seed is planted into soil or other suitable medium. Once these conditions have been fulfilled, growth begins – roots sprout beneath the soil while shoots develop above.
Once a seedling matures, its seeds become ready for dispersion by wind, water or animals to new locations and can begin their lifecycle once again – this process of asexual reproduction.
Some plants can reproduce sexually as well, producing flowers and seeds through pollination, the process by which male reproductive cells (called pollen ) are carried from one flower anther to the stigma of another of their same species by wind or insects and then combined with female gametes called ovules via fertilisation to create a zygote, leading to flower development and seed production.
Meiosis then takes place, producing haploid gametes. This only occurs in plants as diploid eukaryotic organisms have two sets of chromosomes and their unique ability to switch between sexual reproduction and asexual reproduction is what gives plants their extraordinary adaptability in changing environments. Fungi and algae also share this feature but don’t engage in sexual reproduction directly.
Seedlings
Seeds come in all shapes and sizes, but at their center lies an embryo – a tiny baby plant with root, stem and leaf parts – ready to bloom once conditions are optimal. Protected by an outer shell layer, it waits patiently until water, appropriate temperature and suitable location (such as soil) come together for it to begin its journey of germination – an event known as germination.
As soon as a seed germinates, it will produce a stem to transport nutrients from its roots to other parts of the plant and capture sunlight through photosynthesis to produce food for itself. When matured plants reach maturity they will begin producing flower buds in preparation for reproduction.
Flowers are unique structures made up of both male and female parts, used for sexual reproduction through pollination. Pollen carried by wind or insects lands on the female parts, where it lands upon pistils where it fertilises, producing seeds which will later be distributed by plants to other locations to start new plants. As seedlings mature into full grown plants with stronger roots and larger leaves compared to their initial state; their seeds produced will also increase in size as generations alternate – an effect often observed among vascular plants as well as bryophytes like mosses.
Maturity
Once a seed germinates, it begins to rapidly expand – first as a seedling and later as an adult plant. With each stage comes growth, differentiation and eventual maturity that eventually culminates in pollination and seed production before finally dying off and continuing the cycle to perpetuate species survival.
At this stage, plants become an excellent source of carbon (C), nitrogen (N), and other micronutrients. Leaf senescence plays an essential role in recycling C and N; this allows a plant to continue its lifelong journey towards maturity.
Senescence occurs when there is an imbalance between synthesis of signals that induce it and available resources for cell growth, leading to an eventual outstripping of supply resulting in the gradual reduction of viability of tissue over time; this process is known as the “senescence window concept”.
Hexaploid organisms utilize senescence at various points during development to aid with the maturation of their gonads and germ cells, while sexually reproduced organisms (hemimetabolous insects and flowering plants) experience increased rates of senescence during larval stages to prepare their bodies for sexual reproduction. Senescence may even be used to regulate young plants’ rate of growth and nutrient uptake as this depends on available nutrients that they can consume and utilize.
Flowers
Sprouting, seed germination or seedling growth is the initial stage in any life cycle. When all three necessary conditions – water, oxygen and warmth – are fulfilled for seeds to germinate successfully, their hard seed coat is broken open, and sprouting begins – which could take anywhere between one day to several weeks depending on conditions.
As plants expand, they produce buds which bloom into flowers. Each flower possesses male and female organs known as stamen and pistil, respectively, to facilitate pollination by insects. Brightly-colored and strongly scented blooms are often brightly hued and strong-scented to attract pollinating insects; male parts produce pollen grains which are dispersed via wind to pistils of other similar species flowers, where fertilization occurs and seeds are created.
Fertilised flowers release seeds into the environment through fertilisation. Some seeds, like those produced from dandelions, float easily on the wind over long distances while others travel via birds or squirrels; still others hitchhike on water lilies while some are deliberately dispersed by humans when people plant gardens.
All plants go through a process of germination, seedling growth, pollination and seed spreading to produce their offspring. Flowering plants – angiosperms – stand out as being particularly advanced; they have developed special features to attract pollinators and spread seeds more successfully, enabling more controlled reproduction than other forms such as ferns or bryophytes.
Pollination
Plants undergo an intricate lifecycle that begins with seed germination, followed by growth and development into a mature plant capable of producing seeds for pollination and fertilization; eventually these seeds germinate into new plants with their own life cycles that begin once again.
Sexual reproduction involves the alternation of generations; that is, a haploid gametophyte with one set of chromosomes changes into a diploid sporophyte with two sets of chromosomes during sexual reproduction in both vascular plants and nonvascular plants, such as bryophytes.
Flowering plants contain two male parts called anthers that produce pollen grains containing male genetic material, known as pollen grains. A stigma on each flower contains an arrangement to carry this pollen grain towards the female part, known as an ovary, where egg-shaped structures contain eggs known as ovules; pollen then fertilizes these eggs and turns them into seeds, further expanding ovaries that will develop into seeds later.
Pollination relies on wind and insect activity to transport male gametes onto stigmas of plants. If pollination fails, reproduction cannot take place and new generations of plants cannot come into being.
Flowering plants often possess mechanisms that enable them to postpone self-pollination when pollinators are scarce and unreliable, giving the plant more time for another pollinator or wind to carry the pollen to its proper female portion of the plant.