Plant starch and fibres

• Many of the cells that supply energy are filled with amyloplasts which starch-storage organelles that can be used for energy when the plant is in different conditions. .
• Cellulose fibres may be further toughened and strengthened by lignin, turning them into what we recognise as wood
• Plant fibres have been used to make ropes, paper and cloth. The fibres are very long sclerenchyma cells and xylem tissue and are usually very tough and strong.
• Cellulose and lignified cellulose are not easily broken down either by chemicals and enzymes
• Plants have great tensile strength - they cannot be easily broken by pulling (under tension) and they are flexible
• Retting is a process using the action of microorganisms and moisture on plants and dissolve away most of the cellular tissue and lectins surrounding the fibres, facilitating the separation of the fibre from the stem. One example of the fibres that uses retting is cotton
• Plastics are synthetic polymers - long-chain molecules made of repeating units of small monomer molecules. Now, modern materials are being developed from natural products to avoid environmental problems caused by plastics
• Plastics are polymers and they are made from petrochemicals originating from oil which is a non-renewable source. These plastics are non-biodegradable (cannot be broken down by decomposers), leasing to plastic pollution on a large scale
• Bioplastics based on biological polymers like starch and cellulose. They have two main benefits:

  • they are a sustainable resource
  • bioplastics are biodegradable (but the process can be slow)
• However, if the land is used to grow crops for sustainable developments like biofuels or bioplastics, it is no longer available for growing crops for
• We can burn bioplastics when we no longer use them. Although this seems unnecessary, when biofuels break down they produce methane which is very damaging to the environment (more than the carbon dioxide released when burned). Also the energy produced during burning can be used to generate electricity and make more plastics.
• Bioplastics are also very expensive