This makes it easier for new plants to grow further away from their parents. Funny how this is also reminiscent of humans, in a way, although it happens much earlier with plants. This is important for the expansion of the range of the species. This is also why seeds are crucial for our planet and the survival of a large number of plants.
Plants need to take advantage of many habitat opportunities, and by dispersing seeds further away, they can do just that. There are many disturbances in nature, including some ecological processes, which is why plants need to search for new habitats continually. Seeds are used for this. Of course, they also allow us humans to plant them anywhere we want and grow whichever plant we need to survive.
Some plant species are of vital importance to us; we need them as a source of food. However, there are also seeds of plants we need for raw materials. These materials can be used for manufacturing industrial chemicals, for example.
Uneven germination due to slow growth, differences in soil moisture or temperatures, or planting depth of the seed, can result in seedlings of different sizes. This can especially cause problems when transplanting a tray of seedlings; half are ready to plant in the field, and the other half are too small, with root balls that don't slide easily out of the tray cells. In the greenhouse, one way to achieve rapid, uniform germination is to use germination mats under the trays.
These mats allow you to set the temperature according to seed requirements. Make sure you maintain optimal temperatures for your crop see Table 1.
Providing good air circulation during germination and early seedling growing will help to control diseases in this early stage. We cannot control conditions in the field like we can in the greenhouse, but we can still take steps to make sure that seeds planted directly into the field germinate uniformly. A fine-textured seed bed provides good growing conditions, ample seed-to-soil contact, and the ability to plant to a uniform depth.
Planting when the soil temperatures are near optimum will hasten germination and emergence of the seedlings. Sometimes in the rush of spring planting, seeds are sown in soils that are too cold. This can result in slow germination, weakened and diseased seedlings, and even plant death. It is much better to delay planting until soils warm up. The optimal temperature for growing seedlings may be different from optimal germination temperatures. Table 2 shows the range of day and night temperatures that are best for growing seedlings in a greenhouse, where temperatures can be controlled.
Cooler temperatures generally slow down growth, and warmer ones speed up seedling growth. All seedlings need ample light to grow. If light levels are low or if seedlings are too crowded as they grow, the stems will stretch as the plants seek more light, resulting in weak, "leggy" transplants. Consider supplemental lighting if greenhouse light levels are low.
The length of time that seedlings need to grow in the greenhouse before they are big enough to transplant into the field varies by crop. Tomato and pepper seedlings may take five to seven weeks to produce, while cucumbers and squash are ready to transplant after three to four weeks in the greenhouse.
But all transplants need to be hardened off before going from the greenhouse out to the field, or they will be damaged by the harsher conditions. To harden off seedlings, gradually expose them to conditions they will have in the field.
Plants may show some signs of wilting, but do not let plants wilt excessively. After a day or two, weather permitting, set the trays outside of the greenhouse for five to seven days prior to planting. If it is very hot and sunny, provide some shade for the seedlings for the first day or two. Plants that are hardened off in this manner will be better able to tolerate transplanting, and continue to grow in the field uninterrupted. Seeds are the foundation of human and animal life on earth.
The foods we eat, the fibers in the clothes we wear, and most of the products we use in our daily lives are created from seeds-from corn, cotton, and canola to wheat, barley, and soybean, to vegetables, flax, and flowers. As the delivery mechanism for new plant technologies and varieties, seed is also the crux of agriculture.
Quality seed is essential for growing quality crops. And demand is continuing to grow. Between and , it is expected that the world population will increase by over 1. Thanks to continuous improvement in productivity and technology, the seed industry is meeting the expanding needs of the global market.
It is feeding more people, producing healthier foods, using fewer resources and more renewable materials, while offering quality products with more diversity. Coevolution of flowering plants and insects is a hypothesis that has received much attention and support, especially because both angiosperms and insects diversified at about the same time in the middle Mesozoic.
Many authors have attributed the diversity of plants and insects to pollination and herbivory, which is the consumption of plants by insects and other animals. This is believed to have been as much a driving force as pollination. Coevolution of herbivores and plant defenses is observed in nature.
Unlike animals, most plants cannot outrun predators or use mimicry to hide from hungry animals. A sort of arms race exists between plants and herbivores.
Other plants are protected by bark, although some animals have developed specialized mouth pieces to tear and chew vegetal material. Spines and thorns deter most animals, except for mammals with thick fur; some birds have specialized beaks to get past such defenses. Plant defenses from herbivory : a Spines and b thorns are examples of plant defenses. Herbivory has been used by seed plants for their own benefit in a display of mutualistic relationships. The dispersal of fruit by animals is the most striking example.
An extreme example of collaboration between an animal and a plant is the case of acacia trees and ants. The trees support the insects with shelter and food. In return, ants discourage herbivores, both invertebrates and vertebrates, by stinging and attacking leaf-eating organisms.
Grasses are a successful group of flowering plants that are wind pollinated. They produce large amounts of powdery pollen carried over large distances by the wind. The flowers are small and wisp-like. Large trees such as oaks, maples, and birches are also wind pollinated. More than 80 percent of angiosperms depend on animals for pollination: the transfer of pollen from the anther to the stigma.
Consequently, plants have developed many adaptations to attract pollinators. The specificity of specialized plant structures that target animals can be very surprising. Many bird or insect-pollinated flowers secrete nectar, a sugary liquid. They also produce both fertile pollen for reproduction and sterile pollen rich in nutrients for birds and insects. Butterflies and bees can detect ultraviolet light. Large, red flowers with little smell and a long funnel shape are preferred by hummingbirds who have good color perception, a poor sense of smell, and need a strong perch.
White flowers that open at night attract moths. Other animals such as bats, lemurs, and lizards can also act as pollinating agents. Any disruption to these interactions, such as the disappearance of bees as a consequence of colony collapse disorders, can lead to disaster for agricultural industries that depend heavily on pollinated crops. Animal-aided pollination : As a bee collects nectar from a flower, it is dusted by pollen, which it then disperses to other flowers.
Human life has become dependent on plants for the qualities and developments that they provide, which include medicine and food production. Seed plants are cultivated for their beauty and smells, as well as their importance in the development of medicines.
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