Modifications of the Parenchymatous cells, Hairs or Trichomes
Types of plant cells part 6
التحورات في الأغشية النباتية المتنية "الخارجية", الشعيرات النباتية
أنواع الخلايا النباتية, الجزء السادس
Clinical Pharmacy, Pharmaceutical Botany & pharmacognosy section
علوم الصيدلة السريرية, قسم علوم النباتات والعقاقير الطبيعية
Available in both English & Arabic Languages
متوفرة باللغتين العربية والإنجليزية
مناقشة إسماعيل مرتضى ….. Discussed by Ismail Mortada

إن دراسة النباتات, تشريحيا ووظيفيا وكيميائيا, كانت وما تزال من أساسيات العلوم الطبية والصيدلانية, ومن دراسة النباتات إستطاع الإنسان القديم والمعاصر أن يكتشف أساليب طبية مختلفة لمحاربة الأمراض, والتعامل مع السموم وإبتداع الأنظمة الغذائية الصحيحة, وإنني أستطيع القول بشكل مريح جدا بأن دراسة النبات كيميائيا وتشريحيا, هو مهم كمثل دراسة الإنسان كيميائيا وتشريحيا, حيث أن المنظومة النباتية بشكل كامل, تعتبر مصدر غني جدا ومتميز للأدوية والعقاقير والأفكار العلمية التي بدونها لما إستطاع الإنسان الوصول لعلوم الطب الحديثة, وإنه لمن المهم معرفة أن كل المخلوقات الحية ومن ضمنها النباتات, تتمتع باجهزة تشريحية كاملة البنية وميكانيزمات عمل فيسيولوجية جاهزة دائما لإثبات أنه لا توجد أي قطعة نسيج على وجه الأرض الا ولها بنيتها وتركيبها الدقيق تبعا لمنظومة الكون والمخلوقات الواحدة
In past lectures, we discussed in general the plants anatomy & morphology & we spoke about different kinds of plants cells, including what is called "The Parenchymatous Cells" which are a basic & important kind of the plants cells & we said that this tissue may have some modifications "cellular modification" which will lead to a new kind of anatomical & morphological structures in the plants tissues, we spoke about the stomata before & now we’ll discuss briefly what is called TRICHOMES or the plants hair simply
In another words, the plants epidermal tissues may be included in some modifications of its cells in which some of those cells may extend to the outside region of the tissue causing what is called "Trichomes" or hairs in the plant, so the trichomes are simply a natural projections outside the epidermal tissues in the plants because of a modification process which is done on the parenchymatous cells which forms this tissue, now depending on the morphology of those projections they could be divided into the following
A) Papillae
B) Hairs or Trichomes
If those projections were short they will be called papillae & the epidermis layer will be called at this time as PAPILLOSED EPIDERMIS, & If the projections were long they will be called hairs or trichomes, the papillae appear as circules in the middle of the epidermal tissues between the other cells & this tissue is appearing normally in most of the petals of the flowers
Picture of papillosed tissue

At the other side, as mentioned just now, there are the hairs or the trichomes, in which the presence or the absence of those hairs + the characters of those hairs are very important in the plants IDENTIFICATION process, so this is an important way of the different ways which are used in the identification of plants & in understanding different types, because each plants category has its’ special morphological charaters including special way of distributing the hair on it & the location of those hairs + their shapes & length also
THE HAIR OR TRICHOMES
The hair which is an out-growth of the epidermal layer is normaly consisted of the following
A) THE BODY: the body of the hair which is the part projecting outside the epidermal tissue, which might be with a Glandular or Non-Glandular Heads
B) THE BASE: Which is the part embedded in the epidermal tissues & which is not visible to outside the tissue itself
Trichomes microscopical view

The hairs shows a great variation in their shapes, sizes & contents & are classified into the following normaly
A) Non-Glandular Hairs
B) Glandular Hairs
The Non-Glandular hairs which are projections without having a gland on their head can be also calssified depending on their structure into the following
A) UNICELLULAR, which includes the following
1- Papillae which are unicellular very short hairs such as in Viola tricolor petals,
2- Cystolith which are unicellular hairs containing Calcium Carbonate such as in Cannabis leaves,
3- Warty Hair which are unicellular thickened walls such as in Senna Leaves
4- Stellate Hairs which are a group of unicellular hairs which appears from the same projection point such as in Hamamelis Leaves
B) MULTICELLULAR, which includes the following
1- Uniseriate hairs which might be in different shapes like normal hairs (Stramonium), collapsed hairs (Digitalis) & T.shaped hairs (Artimisia)
2- Biseriate which might be in 2 raws (Calendula) or in the shape of twin hairs (Arnica)
3- Pulriseriate such as the shugy hair in Cumin
4- Branched Candelabra like in Vebascum
Viola tricolor petals which contains unicellular short projections called papillae as shown in the picture

unicellular trichome containing calcium carbonate

Group of hairs unicellular appearing from the same projection point or as you can say all the hairs are coming from one cell as shown in the picture & called Stellate hair such as in Hamamelis leaves

Multicellular normal uniseriate hair, check out how is it made up of normal hair body which is composed of more then one cell, such as those appearing in Stramonium


Different shapes of trichomes as shown in the following picture

Now the Glandular trichomes are very similar in their shapes to the Non-Glandular types, but they have GLANDS on their heads which differentiate them from the non-glandular types & this is also a very important feature in the plants identification process also, they are divided into the following depending on their morphology also
A) UNICELLULAR STALKS , with either unicellular head or multicellular heads such as in Primla & Belladonna respectively
B) MULTICELLULAR STALKS which are either
1- Uniseriate , with unicellular head like primula or multicellular heads like in Hyoscymus niger
2- Biseriate with a biseriate head such as in Artimisia
3- Pluriseriate stalk with a multicellular head such as in Cannabis
4- Branched Uniseriate Stalk with a unicellular head on each stalk such as Hyscymus muticus
Check the following pictures & recognize the different shapes of trichomes in general




To read the past lectures in this chain of lectures please check the following URL Adresses
Anatomy & Drug Microscopy of Medicinal Plants
mortada8.maktoobblog.com/1536521/anatomy-drug-microscopy-of-medicinal-plants
Types of Plants cells Part 1
mortada8.maktoobblog.com/1536531/types-of-plants-cells-part-1/
Types of Plants cells part 2, Sclerenchymatous Cells
mortada8.maktoobblog.com/1536535/types-of-plants-cells-part-2-sclerenchymatous-cells/
Types of plants cells part 3, The Vascular System
mortada8.maktoobblog.com/1536586/types-of-plants-cells-part-3-the-vascular-system/
Types of Plants Cells part 4
mortada8.maktoobblog.com/1536677/types-of-plant-cells-part-4/
Modifications of Parenchymatous cells, Stomata
mortada8.maktoobblog.com/1536717/modifications-of-the-parenchymatous-cells-stomata/
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Modifications of the Parenchymatous cells, Hairs or Trichomes
Types of plant cells part 6
التحورات في الأغشية النباتية المتنية "الخارجية", الشعيرات النباتية
أنواع الخلايا النباتية, الجزء السادس
Clinical Pharmacy, Pharmaceutical Botany & pharmacognosy section
المزيد
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