Variation in the structure and development of foliar stomata in the Euphorbiaceae

The structure and ontogeny of foliar stomata were studied in 50 species of 28 genera belonging to 17 tribes of the family Euphorbiaceae. The epidermal cells are either polygonal, trapezoidal, or variously elongated in different directions and diffusely arranged. The epidermal anticlinal walls are either straight, arched or sinuous. The architecture of cuticular striations varies with species. The mature stomata are paracytic (most common), anisocytic, anomocytic and diacytic. Occasionally a stoma may be tetracytic, cyclocytic or with a single subsidiary cell. The ontogeny of paracytic stomata is mesogenous dolabrate or trilabrate, mesoperigenous dolabrate; that of diacytic stomata is mesogenous dolabrate, whereas that of anisocytic stomata is mesogenous trilabrate; rarely an anisocytic stoma may be mesoperigenous. Hemiparacytic stomata are mesoperigenous unilabrate; tetracytic stomata are mesoperigenous dolabrate and anomocytic stomata perigenous. Abnormalities encountered include four types of contiguous stomata, stomata with a single or both guard cells aborted and persistent stomatal initials. Cytoplasmic connections between the guard cells of two adjacent stomata or the guard cell of a stoma and an adjacent epidermal/subsidiary cell, or both types occurring in a species, were noticed. The stomatal development, distribution, diversity and basic stomatal type with reference to systematics are discussed.     

Action of growth regulators on the cotyledonary stomata ofCucumis sativus L.: Structure and ontogeny

Anomocytic stomata and stomata with single subsidiary cells are commonly observed Sometimes a stoma appears anisocytic. Double cytoplasmic connections between nearby stomata and division of guard cells with persistent or degenerating nuclei are seen in GA. One or more divisions of guard cells, displaced guard cells and single guard cells with or without pore are noticed in SUC. Formation of single guard cells is a common feature in TIBA. Paracytic stomata, one and a half stomata and persistent stomatal initials are seen in SUL. COUM seems to be not inhibitory inCucumis sativus. In COL stomata with unequal guard cells, unequal stomatal cells with thickening in between but without intervening pore, stoma with double pores, persistent stomatal initials which may be solitary or in groups with varying shapes and with one or two nuclei of different shapes are noticed. The growth regulators affect the frequency of stomata, epidermal cells; stomatal index; size of guard and epidermal cells.     

Epidermal Structure and Stomatal Ontogeny in Some Polygonales and Centrospermae

The epidermal structure and ontogeny of stomata in 19 speciesof Centrospermae and two of Polygonales are described. The cellsof the epidermis are polygonal, isodiametric, or elongated invarious directions and arranged irregularly. The anticlinalepidermal walls are thick, sinuous, straight, or arched. Eleventypes of glandular and eglandular trichomes have been observed.Six types of stomata: anomocytic, paracytic, stomata with asingle subsidiary cell, diacytic, anisocytic, and transitionalbetween diacytic and paracytic, have been noticed in the speciesinvestigated. The ontogeny of anomocytic stomata is haplocheilicor perigenous, while that of the other five types is syndetocheilicor mesogenous. Abnormal stomata with a single guard cell, unequalguard cells, aborted guard cells, and arrested development arecommon. Groups of stomata are also frequent but contiguous stomataare rather rare.     

Structure and Development of Stomata in Some Labiatae

The structure and ontogeny of stomata have been studied in 33species of the Labiatae. The mature stomata are diacytic, transitionalbetween paracytic and diacytic, and anomocytic. The anomocyticstomata are haplocheilic or perigenous. The diacytic and thetransitional type of stomata are syndetocheilic or mesogenousas the two subsidiary cells and a pair of guard cells arisefrom the same meristemoid. The diacytic and the transitionalstomata are formed through three successive mitotic divisions.Abnormal stomata with single guard cells, arrested developments,and contiguous stomata have been observed. Contiguous stomataare formed either from two adjacently placed meristemoids orare the result of spatial readjustment during maturation ofthe leaf.     

Epidermal Structure and Ontogeny of Stomata in some Verbenaceae

The present paper deals with epidermal structure and developmentof stomata in 14 species of Verbenaceae. The epidermal cellsare either polygonal, isodia-metric, or elongated in variousdirections, and irregularly arranged. The anticlinal walls arethick, mostly sinuous, occasionally arched or straight. Thesurface of the cuticle shows parallel, rarely corrugated, striations.Some 12 types of eglandular and glandular trichomes, and foliarnectaries are noticed. The mature stomata are diacytic, anisocytic,paracytic, with a single subsidiary cell, anomocytic and perigenous.The development of anomocytic stomata is perigenous, while thatof others is mesogenous or syndetocheilic type. Abnormalitiesnoticed here include contiguous stomata, stomata with a singleguard cell, and aborted guard cells.     

Epidermal Structure and Ontogeny of Stomata in Vegetative and Reproductive Organs of Ephedra and Gnetum

The epidermal structure and development of stomata in vegetativeand reproductive organs of Ephedra foliata and Gnetum ula isdescribed. The epidermal cells are polygonal, isodiametric,or elongated with thick or thin straight, arched, or slightlysinuous anticlinal walls. The cuticle is thin or thick. Papilla-likeunicellular outgrowths are present in Ephedra foliata. The maturestomata are orientated parallel to the longitudinal axes orirregularly. The mature stomata are anomocytic, paracytic, witha single subsidiary cell, cyclocytic, and actinocytic. Arresteddevelopment, contiguous stomata, and stomata with aborted guardcells have been observed. The ontogeny of stomata on differentorgans of these two plants is typically haplocheilic or perigenousbut the stomatal apparatus varies from organ to organ.     

The Epidermal Cells of Tea Leaves

The upper epidrmis of tea leaf consists of cells about 30 40 μ in diameter, with slightly sinuous cell surface and devoid of stomata or hairs. The lower epidermis consists of cells about 50–70 μ in diameter, with more sinuous walls. Stomata confined to the lower surface, surrounded by 3–4 round, subsidiary cells. The upper andlower epidermis of the wild tea of southwest China show the difference in surface texture. Luxuriant wax of the epidermis is in knob or club shape. There are two types of stomata (namely general stomata and stomata of sunken crypts (gland scale)) on the same leaf. The numbers of stomata are distributed 70–100/mm2. Hairs are short and rare, or none. Intercellular flanges between epidermis is steep and thick in wild tea. The protruded parts of the torus are in the form of “foot”. The flanges of the cuticle are rather deep.     

Epidermal structure and development of stomata in vegetative and floral organs ofHybanthus enneaspermus (Linn.)F. Muell

The present paper deals with the epidermal structure and ontogeny of stomata in vegetative and floral organs ofHybanthus enneaspermus. The epidermal cells are either polygonal or elongated with straight, sinuous or arched thick anticlinal walls. The surface of the cuticle shows parallel striations radiating from the guard cells or hair bases. Unicellular and uniseriate bicellular trichomes with verrucose margins have been observed on all organs. The mature stomata are anisocytic, paracytic, anomocytic and transitional between anisocytic and paracytic. The ontogeny of anisocytic and paracytic stomata is syndetocheilic or mesogenous, anomocytic is haplocheilic or perigenous, while that of the transitional type is mesoperigenous. Four types of stomata have been observed on all the vegetative and floral organs and their ontogeny from organ to organ of this plant is constant. Stoma with a single guard cell is the result of disintegration of one of the guard cells before or after pore formation. Contiguous stomata are also occasionally noticed.     

Structure,Ontogeny and Taxonomic Significance of Stomata in Some Cucurbitaceae

Stomatal structure, ontogeny in vegetative and floral organs of 9 genera and 12 species of Cucurbitaceae are described. The stomatal types conform to aperigenous, monoperigenous, diperigenous, hemipara-mesoperigenous and para-mesoperigenous types of Fryns-Claessens & Van Cotthem (1973). Stomatal abnormalities such as contiguous stomata, single guard cells with or without pore, one and a half stomata, degeneration of one or both the guard cells, cytoplasmic connections between guard cells of neighbouring stomata and a guard cell of a stoma and an adjacent epidermal cell, and division of guard cells are described. Stomata index, frequency of stomata, epidermal cells, size of guard and epidermal cells and organwise distribution of stomata are given. Stomatal studies does not support the view that the Cucurbitaceae are related to the Passifloraceae. The inclusion of 9 genera and 12 species studied in the tribe Cucumerineae is justified.     

Development of Normal and Abnormal Stomata in some Araliaceae

The present investigation describes the ontogeny of normal andabnormal stomata for three species of the Araliaceae. The maturestomata are mostly anisocytic, occasionally paracytic, and rarelyanomocytic. Several aberrent patterns of stomatal developmenthave been noticed in anisocytic stomata and a few in paracyticones. The ontogeny of anisocytic and paracytic stomata conformsto the syndetocheilic or mesogenous type, while that of anomocyticis haplocheilic or perigenous.     

Observations on the cotyledonary and hypocotyledonary stomata and trichomes in some Caesalpiniaceae with a note on their taxonomic

The structure and ontogeny of stomata on cotyledons and hypocotyls and the trichomes on hypocotyl are accounted for in eighteen species of Caesalpiniaceae. Trichomes are eglandular, bi- rarely tri-celled, smooth walled or walls wavy with cuticular striations or tubercles. Anomocytic, haplocytic, paracytic, diacytic, transitional, tetracytic, tricytic and cyclocytic stomata occur in different combinations even on the same surface of the cotyledon. In all, there are fourteen combinations. Inspite of the diversity, the most frequent type is anomocytic in most of the species and paracytic in some species of Cassia and Delonix (abaxial) but rarely it is haplocytic or anisocytic. In hypocotyls it is anomocytic. Ontogenetically anomocytic, tetracytic and cyclocytic stomata are perigenous, whereas other types are mesogenous or mesoperigenous. There is an increase in the number of subsidiary cells by their division or the neighbouring perigenes assuming their shapes. About eight such types are described. A pair of stomata has a common subsidiary cell. Twelve types of guard cell and stomatal approximation abnormalities are described. A range in the number, size and shape of the nuclei in guard cell are recorded. Megastomata (giant stomata) are observed in Parkinsonia and Tamarindus. The taxonomic significance of the stomata is also discussed.     

Some Differences in the Responses of Stomata of the Two Leaf Surfaces in Cotton

Some differences in the responses of the upper and lower stomatain cotton (Gossypium hirsutuni) are presented. These differenceswere observed in the course of some studies in which the transpirationof the two leaf surfaces was measured under controlled environmentconditions and the transpiration data used as an estimate ofstomatal response. In darkness the upper stomata were more or less effectivelyclosed while the lower stomata were partially open. Upon illuminationof the leaf with non-saturation or saturation radiation theupper stomata were slower to open than the lower stomata. Thereductions in stomatal aperture which occurs with the increasein age of leaves commenced earlier in the upper stomata andproceeded at a faster rate than the lower stomata. Sudden exposureto saturation radiation caused the stomata of the two leaf surfacesto oscillate. These oscillations were not observed in youngleaves but in older leaves. During ageing of leaves oscillationsof the upper stomata commenced earlier than oscillations ofthe lower stomata. When the petiole was excised in darknessor light the upper stomata showed a transient increase but notthe lower stomata. Gossypium hirsutum, stomatal responses, transpiration     

Studies on the structural and developmental variation and distribution of stomata in the Rubiaceae

The structure and ontogeny of the stomata has been studied in 26 species of Rubiaceae, in relation to their organographic distribution. The stomata are mostly paracytic on the leaves, but vary on other parts, particularly on the floral disk, where they are exclusively anomocytic. The foliar stomata are mesogenous and paracytic, but may be either dolabrate or trilabrate in origin. The disk stomata are perigenous and are probably derived from the mesogenous paracytic ones by the loss of divisive potential of their meristemoid due to anthogenetic factors. They are regarded to be hydathodal in function. If the dendroid habit is regarded as primitive, in the family, trilabrate stomata were quite possibly derived from dolabrate ones, which are mostly associated with the dendroid habit. Evidence from stomatal ontogeny is shown to be taxonomically important in the Rubiaceae.     

The role of cytoskeleton in stomata functioning

The main question in this review is of whether and how the cytoskeleton of guard cells is involved in stomata movements. The main function of stomata is the regulation of the rate of gas exchange between the plant environment and underlying plant tissues. As a result of special morphology and anatomy GCs form the stomatal pore. It can open or close in a controlled manner via internal or external signal-induced changes in GCs turgor pressure, volume and shape. The mechanism of stomata movement is a complex process. A network of actin microfilaments and microtubules, dynamic polymers collectively known as the cytoskeleton forms protein fibril systems in GCs. CT elements are dynamic structures, interconnected to different cell structures. The organization of CT during morphogenesis of stomata is very important in establishing the size and shape of GCs. It is well documented that AFs and MTs are involved in stomata movements and can modify the ability of GCs to respond to environmental and hormonal stimuli. Data gathered clearly suggest that the organization of CT elements is not a direct effect of stomata movements. Several investigation procedures for study of the CT role in stomata functioning, including GCs treatment with anti-CT drugs (disrupters or stabilizers), have been analyzed and discussed in this review but the question of what role AFs and MTs play in stomata movements and how they work still remains open. The availability of new CT visualization techniques and the usage of mutants to study this problem is a good perspective for further research.     

Epidermal Structure and Development of Stomata in some Annonaceae

Epidermal structure and development of stomata are studied in20 species of the Annonaceae. Epidermal cells are polygonalor irregular in outline, isodiametnc or elongated with straight,arched, or sinuous anticlinal walls. Cuticular striations radiatingfrom guard cells or hair bases are noticed. Four types of trichomesand secretory cells are seen. The mature stomata are paracyticwith 2–6 subsidiary cells, non-contiguous at both poles,or contiguous at one or both the poles. The increase in numberof subsidiary cells is due to their divisions. Contiguous stomata,arrested development, single guard cell, and degeneration ofguard cells are observed. The development is either syndetocheilicor mesogenous.     

中国蓼属头状蓼组植物叶表皮微形态及其分类学意义

采用光学显微镜对中国蓼属头状蓼组17种7变种植物的叶片下表皮微形态进行了观察研究,结果表明,其叶片下表皮微形态特征分为4种类型:(1)气孔器类型为无规则型,表皮细胞不规则形,垂周壁波状或深波状;(2)非典型不等型,偶有无规则型,表皮细胞多边形或不规则形,垂周壁弓形、波状或深波状;(3)平列型,表皮细胞不规则形,垂周壁深波状;(4)平列型兼有非典型不等型,表皮细胞不规则形,垂周壁波状。根据其叶片下表皮气孔器类型,结合该组植物形态、习性等特征,将中国蓼属头状蓼组植物划分为4个系,即掌裂叶系、多年生系、蓼子草系以及一年生直立系。     

A STRUCTURAL AND FUNCTIONAL STUDY OF THE COORDINATED REACTIONS OF INDIVIDUAL COMMELINA COMMUNIS L. STOMATA (COMMELINACEAE)

Opening and closure movements of individual stomata were analyzed by light microscopy, scanning electron microscopy, and time-lapse photomicrography. Turgor-pressure-induced changes in pore shape of Commelina communis L. stomata were observed in vivo and in fixed material. The ventral wall of the guard cells undergoes three-dimensional alterations during opening and closing. Stomatal aperture increases with increase in light intensity and with decrease in CO₂ concentration as previously described, while reactions to relative humidity and anaerobiosis are somewhat divergent from common experience. Low humidity induces opening rather than closure of stomata in well watered greenhouse plants, and lack of oxygen induces consecutive opening and closure movements. Individual stomata characteristically open by three distinct steps: (1) rapid opening; (2) immobility or slow closure; (3) relatively rapid opening. Since the timing of the second step varies for individual stomata, it is obscured by methods that integrate the responses of several stomata. The movements of individual stomata are well synchronized, but active communication between stomata in different areas can not be confirmed.     

Observations on the structure and ontogeny of stomata and trichomes on developing and mature pericarps ofCassia occidentalis L

Paracytic, anisocytic, anomocytic, transitional forms, tetracytic, cyclocytic stomata and partly and completely amphicyclic forms are found, often on the same surface, in nine combinations. The most frequent type is paracytic. A few morphological variations in the basic types and eight types of abnormalities in stomata are recorded. The stomatal ontogeny may be mesogenous, mesoperigenous or perigenous. Trichomes are multicellular glandular club-shaped and unicellular eglandular. The taxonomic significance of stomata is indicated.     

Epidermal studies in some Indian cultivars of Bougainvilleas

Epidermal studies in fifteen Indian cultivars of Bougainvilleas are described. The epidermal cells are polygonal isodiametric, or elongated with thick straight arched or slightly sinuous walls. Parallel culticular striations are radiating from guard cells. The mature stomata are anomocytic, paracytic and with a single subsidiary cell. The abnormal types noticed are: single guard cells with or without pores, arrested development, variously oriented contiguous stomata, cytoplasmic connections between nearby stomata and epidermal or subsidiary cells, and persistent stomatal cells. The development of anomocytic stomata is perigenous while that of the other types is mesogenous. Fifteen cultivars of Bougainvilleas are separated on the basis of bract colour, stomatal frequency and index per unit area.     

Cellular Interactions in the Development of Stomatal Patterns in Vinca major L

The development of the leaf epidermis of Vinca major L. wasfollowed in situ by epi-illumination microscopy and evidencewas sought for cellular interactions. Stomata were often foundto be initiated in adjoining cells. The epidermal cells whichseparated such stomata when they had matured were formed fromthe same cells as the stomatal complexes themselves. The presenceof developing and mature stomata may influence only the orientationof divisions in neighbouring cells, and not the initiation andmaturation of stomata. There is great variability in the relativeorientation, timing and number of divisions which intervenebetween the first unequal division and the maturation of a stomaas well as the location of stomata relative to the spongy mesophylland minor veins. The results indicate that continuous short-rangeinteractions between the future guard cells and the adjoiningcells, rather than interactions between future stomata or afixed programme of development, are essential for the formationof the pattern of functional stomata in the mature leaf. Vinca major L., cell lineage, cellular interactions, development of stomata, epi-illumination microscopy, meristemoids, patterned differentiation, stomata