We all know that plants produce the atmospheric oxygen which other organisms living on the earth inhale and it is also evident that almost everything that we eat comes directly or indirectly from plants. Even the fossilized plants provide energy in the form of fossil fuel and much of humanity’s understanding of genetics and molecular biology comes from the study of plants. Gregor Mendel, recognized as the founder of modern genetic material studied the Pea plant (Pisum sativum) to unravel the laws of inheritance. His work was published in 1865 and later proved to provide critical evidence in support of Darwin’s theory of evolution. Botanist Hugo DeVries based his findings on Mendel’s work and is credited for suggesting the concept of “genes”, introducing the term “mutation” and for developing the mutation theory of evolution. It is for reasons such as these that plant growth and development has been extensively studied through history.
Plants grow throughout their lives through a combination of cell growth and cell division known as mitosis. Plant growth is generally indeterminate due to the presence of meristems in their bodies. Meristem is a type of plant tissue consisting of cells that can continue to divide and differentiate, giving plants the ability to grow and repair. Primary meristem allows a plant to grow in height or length, propelling the roots into the ground and the stem or shoot through the air, mediated by the presence of apical meristems at the tips of roots and shoots. These meristems consist of procambium which produces new xylem and phloem. Secondary meristem allows for growth in diameter in woody plants and consists of the vascular cambium that produces secondary xylem towards the centre of the stem or root and the secondary phloem towards the outside of the stem or root.
Let us learn about the growth habits of the Bamboo plant.
Scientific Classification of Bamboo
Growth And Development in Bamboo
Bamboo is an evergreen perennial grass that belongs to the subfamily Bambusoideae of the plant family Poaceae, that produces a hollow stem. Herbaceous plants do not have secondary growth and in bamboo, as in other grasses, the internodal regions of the stem are hollow. The vascular bundles (xylem and phloem tissue) are scattered throughout the stem and the dicotyledonous woody xylem is absent in bamboo. As a result of the absence of secondary growth of wood, monocots such as bamboo tend to be columnar rather than tapering. Bamboos are some of the fastest-growing plants in the world that can grow at a rate of almost 1 meter or about 36 inches per day. A bamboo shoot grows in height and diameter for approximately 60 days and attains its maximum height and width during this period. A single bamboo shoot will produce its limbs (branches) and leaves during this period and while the bamboo cane may produce new foliage every year, after the 60-day period of growth, the bamboo cane will never grow in height or diameter again. There are many species of bamboo and despite their diversity, they share many common growth characteristics.
Bamboo shoots emerge early in the growing cycle and grow very quickly. These shoots grow into hollow, jointed stems, reaching their full height and diameter in a single growing season, usually within three to four months after they emerge.
Bamboo stems are called culms and depending on the species of the bamboo, the height of a mature culm can range from one foot to well over 100 feet. A bamboo culm will not grow in height or diameter but will get woodier with age. The culm produces branches and leaves and this foliage is replenished through additional seasons. The average life span of an individual culm is 10 years.
Bamboo species can be categorized into two distinct groups:
- Running bamboos send out horizontal rhizomes beneath the surface of the soil and new shoots grow from lateral buds produced from this underlying rhizome. This habit of runners creates groves of widely spaced culms that spread broadly and aggressively very quickly.
- Clumping bamboos produce vertical shoots rising from buds at the end of rhizomes. The rhizomes themselves do not grow far horizontally. This habit produces closely spaced clumps of culms that do not spread horizontally and are therefore considered ideal for in-house and in-pot growing.
Bamboos seldom flower and do so after a growth cycle comprised of many growing seasons, during each of which, the plant produces many new culms. Bamboos have a varied life cycle and depending on species it can be anywhere between 3 and 120 years. After a bamboo plant flowers, it produces a large number of seeds that can be dispersed by the wind and once a bamboo sets seed, it dies.
Bamboo Life Cycle
- Initial Planting: Initial bamboo never grows in height or diameter again.
- 1 st Spring: New shoots emerge during spring and can grow up to 4 feet per day.
- Late 1 st Spring: New growth cycle usually lasts 60 days.
- 1 st Summer: After the 60-day growth period a single bamboo cane will never grow again.
- 2nd Summer: The bamboo grove uses energy from existing canes to produce larger and more numerous spring growth.
- 3 rd Summer: The bamboo grove continues producing larger canes until maturity is reached, usually 7-10 years after planting.
Bamboo is the only grass that can develop into a forest. New groves appear after every growing season. Planting or cultivating bamboo can be a challenge especially if it has to be done by sowing seeds since Bamboos flower so seldom and seed very late into their growth cycle. Another method of planting bamboos and creating new growth is through vegetative propagation.
Bamboo Rhizome Propagation
- Bamboo rhizome propagation or offset propagation is a traditional vegetative propagation method. A “Bamboo Offset” is the lower part of a single culm usually with 3-5 nodes with the rhizome basal and roots attached. This method of propagation is beneficial because an entire plant system is transplanted.
- Bamboo offsets are collected just before the rainy season or the growing season because the food and nutrient reserves in the rhizome of the bamboo are at their peak during this period.
Obtaining a Bamboo Offset
- The rhizome is collected from a healthy parent clump.
- A bamboo clump aged 1-2 years is selected and cut off at the top at about 3-5 nodes from the ground.
- The rhizome attached to this culm is carefully separated at the rhizome neck and care must be taken to avoid damaging to the rhizome and attached roots when digging out the offset.
- The rhizome and roots are immediately wrapped in banana leaves or gunny bags with moist sawdust for transportation.
- A cut bamboo desiccates and dries up quickly. The top of the culm must be covered soil and cow dung mix to prevent desiccation.
Transplanting Bamboo Rhizomes
- The rhizome of bamboo offset must be dipped in a fungicide solution.
- A deep and wide pit must be dug and kept ready for the bamboo being transplanted.
- The bamboo offset is planted vertically in the pit.
- The top of the culm where it has been cut should not be allowed to dry and so the cavity is filled with soil and cow dung mix.
- Daily watering is recommended in case of prolonged dry weather.
- Weeds must be eliminated and sufficient mulch should be added to the newly transplanted rhizome.
Interesting Facts Related to the Growth of Bamboo
- Flowers of bamboo are rarely seen and develop after 65 or 120 years into the bamboo’s life. All the plants of any single bamboo species will produce flowers at the same time, no matter where they are in the world.
- Bamboos are the fastest growing plants on the planet and unlike other plants, a bamboo plant reaches maturity after 3-5 years.
- Bamboo does not require fertilizers for optimum growth and discarded leaves from the bamboo plant provides all the required nutrients as they decompose.
- The bamboo root system helps prevents soil erosion and keeps the soil around it steady and stable.
- A bamboo plant releases 30% more oxygen into the atmosphere and absorbs more carbon dioxide as compared to other plants
- Bamboo is very self-sufficient and can survive for more than 120 years in the wild