A farmer grows maize in a field where the soil can become dry. Fig. 1 shows a maize plant with long roots spreading sideways and downwards. The table gives ...
Question 1 Report
A farmer grows maize in a field where the soil can become dry. Fig. 1 shows a maize plant with long roots spreading sideways and downwards. The table gives the percentage of plants still upright after seven days without rain. One group had its deep roots cut when seedlings were transplanted. Both groups had similar leaf area at the start.
| Root treatment | Plants upright after 7 days / percentage |
|---|---|
| Roots intact | 86 |
| Deep roots cut | 41 |
(a) What is the difference in percentage of upright plants between the groups? [1]
(b) Describe how the root treatment affected the maize plants. [1]
(c) Explain why deep roots can help a maize plant remain upright during dry weather. [2]
(d) Give one function of roots other than absorbing water. [1]
A plant nursery uses cuttings to produce identical mint plants. Fig. 1 shows a cutting placed in moist compost with two leaves above the surface. The worker removes lower leaves before planting the cutting. A new root system develops from the buried stem. The nursery keeps the cuttings under a clear cover for the first week.
(a) What type of reproduction is used to make plants from cuttings? [1]
(b) Describe why lower leaves are removed before the cutting is planted. [1]
(c) Explain why the clear cover helps the cutting before roots have formed. [2]
(d) Give one advantage of producing many mint plants from cuttings. [1]
Answer Details
Labelled answer diagram:
Maize roots
(a)
\[86-41=45\]
The difference is 45 percentage points. [1]
(b) Cutting the deep roots reduced the percentage of maize plants that remained upright. [1]
(c) Deep roots can reach water lower in the soil. This water maintains cell turgor and helps prevent wilting; deep roots can also help anchor the plant. [2]
(d) Roots anchor and support the plant. Absorbing mineral ions or storing food are also acceptable functions. [1]
Mint cuttings
(a) Cuttings use asexual reproduction, also called vegetative propagation. [1]
(b) Lower leaves are removed to reduce water loss by transpiration. [1]
(c) The clear cover raises humidity around the cutting. This reduces evaporation and transpiration, so the cells are less likely to lose too much water and wilt before roots form. [2]
(d) Cuttings allow rapid production of genetically identical plants with desirable features. No pollination is needed. [1]
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