Morphology of Plants (Class X)

Runners are horizontally oriented stems that grow along the soil surface. Their function is vegetative production. For example, a number of grasses have stolons. Strawberries are generally propagated by crown division method.

Offshoots apply to lateral branches on stems of monocots. Date palm, pineapple, banana and orchids produce offshoots. Bamboo also propagate from offshoots; if left unchecked, they will form whole forests of plants.

In harmful levels of sunlight, specialised leaves, opaque or partly buried, allow light through translucent windows for photosynthesis at inner leaf surfaces, e.g. Fenestraria.

Bulbil is a special multicellular body essentially meant for reproduction. In Agave, the floral buds are modified into bulbils. These bulbils get detached, come in contact with the soil and develop into new plants. In Dioscorea, the axillary bud develops into a bulbil. This bulbil detaches from the mother plant and grows up into a new independent one.

Tendrils are slender, spring-like structures that are coiled spirally. The tendrils are very sensitive. When they come in contact with any support, they coil around the support like stem twiners, e.g. grapes, sweet pea.

Some trees have great plant-like roots that radiate from the base of the stem of the tree. It consists of part root and part stem, e.g. Bombax.

This layer has cells which are loosely packed and are located just beneath the palisade mesophyll. It plays a vital role in holding the products of photosynthesis.

These roots are found in aquatic plants. These roots develop from the nodes of the floating branches. The roots are spongy and are colourless. These roots are present above the level of water. As these roots are spongy and soft, they store air in them, which help the plant in floating. They also help in respiration process.

The growth of pollen tube is not controlled by vegetative cytoplasm. The tube nucleus controls the growth of the pollen tube.

A seed begins to form an embryo following fertilisation and the start of a zygote. The initial division of the zygote results in two cells. The bottom cell develops into a multicellular structure, called the suspensor. It is involved in nutrient uptake from the endosperm and anchors the embryo.

New species are not produced due to self-pollination. Progeny shows less vigor due to continuous self-pollination. New characters are not introduced.

The filaments of stamens are fused to form one bundle, while anthers remain free, e.g. Hibiscus, Abutilon, etc.

The tendrils develop from the apex of the developing leaf, as in Gloriosa. This type of leaf apex is known as the cirrhose.

A chasmogamous flower is usually smaller and requires less energy to produce. It is also structured to bring its reproductive organs into contact, making it more likely that fertilisation will be successful.

Here, both filaments and anthers of the stamens are united throughout their length, e.g. Cucurbita, Lagenaria, etc.

Sclerenchyma is a simple tissue meant for the mechanical function. It is thick-walled and lignified, and is characterised by the absence of living protoplasm. The sclerencyma gives mechanical strength to the plant organ, firmness and stiffness to the part of the plant where it is present.

Parenchyma cells helps in the formation of adventitious buds. It aids in the water storage in succulent plants.

In this case, the adhesion is between stamens and carpels. Anthers unite with stigma to form gynostegium, e.g. Calotropis.

This is an incorrect statement as the seed coat in the mature seed can be a paper-thin layer (e.g. peanut) or something more substantial (e.g. thick and hard in honey locust and coconut), or fleshy as in the sarcotesta of pomegranate.

Insect pollinated flowers have sticky pollen, which sticks to pollinating agents such as insects. Light and feathery pollens are a characteristic of wind-pollinated flowers.