Ipomoea hederifolia stems increase in thickness using a combination of different types of cambial variant, such as the discontinuous concentric rings of cambia, the development of included phloem, the reverse orientation of discontinuous cambial segments, the internal phloem, the formation of secondary xylem and phloem from the internal cambium, and differentiation of cork in the pith. After primary growth, the first ring of cambium arises between the external primary phloem and primary xylem, producing secondary phloem centrifugally and secondary xylem centripetally. The stem becomes lobed, flat, undulating, or irregular in shape as a result of the formation of both discontinuous and continuous concentric rings of cambia. As the formation of secondary xylem is greater in one region than in another, this results in the formation of a grooved stem. Successive cambia formed after the first ring are of two distinct functional types: (1) functionally normal successive cambia that divide to form secondary xylem centripetally and secondary phloem centrifugally, like other dicotyledons that show successive rings, and (2) abnormal cambia with reverse orientation. The former type of successive rings originates from the parenchyma cells located outside the phloem produced by previous cambium. The latter type of cambium develops from the conjunctive tissue located at the base of the secondary xylem formed by functionally normal cambia. This cambium is functionally inverted, producing secondary xylem centrifugally and secondary phloem centripetally. In later secondary growth, xylem parenchyma situated deep inside the secondary xylem undergoes de‐differentiation, and re‐differentiates into included phloem islands in secondary xylem. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 30–40.
-(morphological, anatomical and biochemical studies on the foliar galls of Alstonia scholaris (Apocynaceae)). morphological, anatomical and biochemical alterations in foliar galls of Alstonia scholaris R. Br. induced by the insect Pauropsylla tuberculata (Psyllidae) are described and quantified. Galls occur isolated or agglomerated on the abaxial surface of the leaf. The insect along with the egg deposits some physiologic fluid which act as a stimulant for the induction of the gall. This stimulus brings about hypertrophy followed by hyperplasia of cells next to the location of the deposited eggs. The psyllid presents three nymphal instars, from eclosion of the egg to the adult. hyperplasia in the palisade cells is very distinctly noticed. hypertrophy followed by hyperplasia takes place and brings about elevation of hypodermal and palisade parenchyma which undergoes repeated anticlinal divisions. neoformation of phloematic bundles were distinctly noticed close to the site of infection. With an increase in the growth of the gall, chlorophyll content in the gall tissue decreases. A steady increase of sugar content is noticed. the immature galled tissue showed almost two fold increases in the protein content. the mature galled tissue showed a very high increase in the proline content compared to the immature galled tissue indicating a stressed condition of the galled tissue.key words -hyperplasia, hypertrophy, Pauropsylla tuberculata RESUMO -(estudos morfológicos, anatômicos e bioquímicos em galhas foliares de Alstonia scholaris (Apocynaceae)). Alterações morfológicas, anatômicas e bioquímicas nas galhas foliares de Alstonia scholaris, induzidas pelo inseto Pauropsylla tuberculata (Psyllidae), são aqui descritas e quantificadas. As galhas ocorrem isoladas ou aglomeradas na superfície abaxial da folha. O inseto, juntamente com os ovos, deposita fluidos fisiológicos que atuam como um estimulante na indução da galha. Este estímulo gera hipertrofia seguida por hiperplasia das células localizadas próximas ao local de deposição dos ovos. O inseto apresenta três estágios de instares ninfais, a partir da eclosão do ovo até o adulto. A hiperplasia das células do parênquima paliçádico é bem distinta. A hipertrofia seguida pela hiperplasia ocorre e causa uma elevação da hipoderme e do parênquima paliçadico que sofre repetidas divisões anticlinais. A neoformação de feixes floemáticos é distinta próxima ao local da infecção. Com o aumento no crescimento da galha, o conteúdo de clorofila nos tecidos da galha diminui. Ocorre um aumento constante no conteúdo de açúcares. O tecido da galha madura mostra um aumento grande no conteúdo de prolina quando comparado ao tecido da galha imatura, indicando a condição de estresse do tecido galhado.
Seed exomorphic characters of nine different species of Eragrostis were investigated by Light and Scanning electron microscopy. In the present study the micro-morphological characteristic features of caryopses such as shape, dimension, colour, epidermal cell surface structure and features of anticlinal and periclinal walls were examined. Light microscopy revealed that most of the studied caryopses varied in shape from obloid to ovoid. The caryopses in most of the species of Eragrostis are sticky in nature due to the presence of surface slime cells, which makes them appear shiny and transparent. This morphological feature was able to be observed under SEM but not light microscopy. The nine different species could be differentiated on the basis of shape and position of the hilum and embryo.
Urochondra setulosa grows in marine conditions, while Sporobolus indicus grows near fresh water and sometimes also close to moist places along roadside areas. Both species belong to the same tribe and same family. The two grass species growing under different habitats showed characteristic variations in their morphometric traits of the caryopsis and seedlings. U. setulosa growing in salty area had characteristic features, e.g. leaf and culm with salt deposition, rigid leaf blade with pointed leaf tip, while S. indicus growing near fresh water showed glabrous nodes and internodes. Morphometric analysis of caryopses of both species showed very similar features, without prominent differences in their length, breadth and thickness. But light microscopy and scanning electron microscopic (SEM) studies showed variations. Under light microscopy, features like colour, shape and compression of caryopses showed differences among the species. SEM studies of caryopses revealed a reticulate type of pattern of sculpturing on both dorsal and ventral surfaces, whereas anticlinal and periclinal walls in U. setulosa were elevated with folded walls, while in S. indicus had non elevated undulating walls. In conclusion, each individual grass ecotype evolves some characteristic morphological features to thrive well under a particular environment. Both species studied hereby, grown in different habitats, showed remarkable differentiations in their characters, thus indicating that habitats play a major role in traits of the plant growth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.