The key difference between monocot and dicot leaves is that monocot leaves have parallel veins while dicot leaves have branching veins with a prominent midrib.
The leaf is the main site of photosynthesis in green plants. A leaf is fixed to the stem of a plant at the node. Internode is the distance between two adjacent nodes of the stem. Some leaves possess a leaf stalk or a petiole to attach to the stem while some leaves do not. Moreover, leaves of dicot plants and leaves of monocot plants show differences. In dicot leaves, the petiole continues as the midrib, forming a network of veins called reticulate venation.
CONTENTS
1. Overview and Key Difference
2. What are Monocot Leaves
3. What are Dicot Leaves
4. Similarities Between Monocot and Dicot Leaves
5. Side by Side Comparison – Monocot vs Dicot Leaves in Tabular Form
6. Summary
What are Monocot Leaves?
Monocot leaves are the leaves of monocot plants. These leaves show parallel venation. They do not possess a midrib or branching veins. Also, both sides of the monocot leaf are more or less the same. Therefore, they are described as bicollateral leaves. Furthermore, their leaf blade is flat and thin.
Figure 01: Monocot Leaves
Most monocot leaves are linear in shape. And, the mesophyll cell layers in these leaves are not differentiated. Also, the stomata are equally distributed on both epidermises. Furthermore, the guard cells of these leaves are mostly dumb-bell shaped. Besides, normally, the leaves join into the stem in such a way that light falls equally on both surfaces.
What are Dicot Leaves?
Dicot leaves are the leaves of dicot plants. The major characteristic of dicot plants is the leaf venation. Dicot leaves have a midrib and branching veins. Hence, their venation pattern is reticulate. Also, these leaves show different shapes other than linear shape. Furthermore, the leaves join with the stem in such a way that only the upper surface of the leaf receives sunlight (dorsoventral leaves). Therefore, these leaves possess a well-marked differentiation of cell layers or tissue layers within the leaf.
Other Characteristics
The outermost layer on the dorsal and ventral surfaces is the epidermis. It consists of a tightly packed layer of living cells. Normally, these cells do not have pigments. Hence, the light can easily penetrate through the epidermal layer to the photosynthetic cells below. On the lower epidermis in dicots, there are large numbers of stomata surrounded by two kidney-shaped guard cells with chloroplasts. Generally, upper epidermis does not contain stomata in order to prevent excess water loss.
Figure 02: Dicot Leaf
The palisade layer is below the upper epidermis and it is the main site of photosynthesis in leaves. A normal mesophytic leaf has only one layer of palisade cells. Palisade cells are rich with chloroplasts in order to carry out photosynthesis efficiently. Apart from that, there are several layers of round shaped spongy parenchyma cells between the lower epidermis and the palisade cells. They have large intercellular spaces, continuous with the stomatal or respiratory chambers near stomata. They also have chloroplasts. In the midrib region, just below the upper and lower epidermis, there are several layers of collenchymas. The midvein and the lateral veins consist of xylem tissues towards the upper epidermis. Towards the lower epidermis is phloem tissues. Moreover, lateral veins may be found in the spongy parenchyma region. Bundle sheath cells surround all the veins including the midvein of a dicot leaf.
What are the Similarities Between Monocot and Dicot Leaves?
- Monocot and dicot leaves are the sites of photosynthesis on both plant types.
- They possess chloroplasts.
- Moreover, they carry out photosynthesis efficiently.
- Also, they contain stomata and guard cells.
What is the Difference Between Monocot and Dicot Leaves?
The key difference between monocot and dicot leaves is that monocot leaves possess a parallel venation while dicot leaves possess a reticulate venation. Furthermore, monocot leaves are bicollateral leaves while dicot leaves are dorsoventral leaves. Hence, both sides are similar in monocot leaves while the upper and lower sides are different in dicot leaves. So, this is also a significant difference between monocot and dicot leaves. Generally, monocot leaves are mostly linear. But, dicot leaves are in different shapes.
Another significant difference between monocot and dicot leaves is the distribution of stomata. Monocot leaves have stomata on both sides while dicot leaves have stomata only in the lower epidermis. Moreover, a further difference between monocot and dicot leaves is that the monocot leaf blade is flat and thin while dicot leaf blade is broad. Besides, the guard cells of monocot leaves are dumbbell shaped while guard cells of dicot leaves are kidney shaped. Therefore, this is also a major difference between monocot and dicot leaves.
Moreover, an additional difference between monocot and dicot leaves is that both surfaces of the monocot leaf are equally green in colour. But, the upper surface of the dicot leaf is dark green while the lower surface is light green.
Summary – Monocot vs Dicot Leaves
Leaves of monocot plants and leaves of dicot plants show many differences. The key difference between monocot and dicot leaves is the venation pattern. Monocot leaves show parallel venation while dicot leaves show reticulate venation. Furthermore, monocot leaves are flat and thin while dicot leaves are broad. Also, both sides of the monocot leaves are similar and equally coloured while upper and lower surfaces of dicot leaves are different and differently coloured. Besides, there is another difference between monocot and dicot leaves in stomata distribution. Monocot leaves have stomata in both epidermises while dicot leaves have stomata only in the lower epidermis. Thus, this is the summary of the difference between monocot and dicot leaves.
Reference:
1. “Leaf.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 14 Feb. 2019, Available here.
2. “Leaves.” Lumen, Boundless Biology, Available here.
Image Courtesy:
1. “551339” (CC0) via Pxhere
2. “Lisc lipy” By Krzysztof P. Jasiutowicz – first upload pl.wikipedia 11:26, 10 jul (lipiec) 2004 by Kpjas as pl:Grafika:Lisc lipy.jpg (CC BY-SA 3.0) via Commons Wikimedia
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