Plant morphology

About: Plant morphology is a research topic. Over the lifetime, 1174 publications have been published within this topic receiving 24418 citations. The topic is also known as: phytomorphology & morphology of higher plants.

Morphological and physicochemical descriptors for characterization of mangaba tree germplasm.

Abstract: The objective of this study was to evaluate and select morphological and physicochemical descriptors for the characterization of mangaba tree germplasm. We used 30 descriptors in 54 plants from 10 accesses in the fruiting stage (CA, AB, PT, PR, TC, PA, LG, BI, IP and AD) from the Active Germplasm Bank of Embrapa Coastal Tablelands located in the Experimental Field of Itaporanga d’Ajuda, Sergipe, Brazil, faithful trustee of the species. The diversity was verified between and within the accesses, however, without direct relation with its origins. The mean vitamin C content was considered high (394.45 mg/100g) and there was no difference between the accesses. There was a significant difference for most descriptors related to the growth of the plants and the physicochemical characteristics of the fruits. The results are important for the conservation actions of the species and individuals selection for future improvement programs.

Phenotypical modifications of micropropagated grapevines

Abstract: Grapevine commercial micropropagation has been constrained by the possibility that the phenotype of the resulting plants may be modified. In this work, we observed the characteristics of self-rooted grapevine plants (cvs Moscato and Barbera), derived from micropropagation (MP) or from woody cuttings (C) over several years after they had been planted in the vineyard. Observations concerned phenology, vegetative growth, ampelography, production, and juice composition. For ampelometric description, the main parameters of adult leaves were measured by means of a computerised graphic digitizer, After some years in the vineyard, most differences in vegetative growth and production were not significant, with the exception of the yield in 'Barbera': MP plants produced more compared to C plants. No significant difference was observed in fertility, vegetative vigour and berry juice composition. On the contrary important morphological characters were still different among leaves of MP and C plants. MP plants often had smaller leaves, with deeper lateral sinuses and a more pronounced hairiness on the veins of the leaf lower side. In 'Barbera', lateral sinuses of MP plants had frequently an atypical form but the frequency of this feature lowered as plants grew older. Leaves of 'Moscato' plants had frequently 5 lobes instead of 3. Discriminant analysis was effective in separating leaf samples collected from plants obtained with different propagation systems, In grapevine, modifications in leaf features may lead to some problems in the ampelographic characterisation of clones. Such morphological modifications, resulting from in vitro culture of vines, are supposed to be due to the rejuvenation induced by this culture method, and to the fact that some juvenile characters could persist for some time after transfer to the vineyard.

Variation in leaf structure: an ecophysiological perspective.

Abstract: 1. Biotic And Abiotic Consequences Of Differences In Leaf Structure 2. A Mechanical Perspective On Foliage Leaf Form And Function 3. Modelling Leaf Expansion In A Fluctuating Environment: Are Changes In Specific Leaf Area A Consequence Of Changes In Expansion Rate? 4. Specific Leaf Area In Barley: Individual Leaves Versus Whole Plants 5. Leaf Structure And Specific Leaf Mass: The Alpine Desert Plants Of The Eastern Pamirs, Tadjikstan 6. Contribution Of Carbohydrate Pools To The Variations In Leaf Mass Per Area Of Tomato Leaves 7. Leaf Structure And Chemical Composition As Affected By Elevated CO2: Genotypic Responses Of Two Perennial Grasses 8. The Relationship Between Leaf Composition And Morphology At Elevated CO2 Concentrations 9. Profiles Of Photosynthetic Oxygen Evolution Within Leaves Of Spinacia Oleracea 10. Leaf Anatomy Enables More Equal Access To Light And CO2 Between Chloroplasts 11. Assessing Leaf Pigment Content And Activity With A Reflectometer 12. Relationships Between Photosynthesis, Nitrogen And Leaf Structure In 14 Grass Species And Their Dependence On The Basis Of Expression 13. Low-Light Carbon Balance And Shade Tolerance In The Seedlings Of Woody Plants: Do Winter Deciduous And Broad-Leaved Evergreen Species Differ? 14. Specific Leaf Area And Leaf Dry Matter Content As Alternative Predictors Of Plant Strategies 15. A Comparison Of Specific Leaf Area, Chemical Composition And Leaf Construction Costs Of Field Plants From 15 Habitats Differing In Productivity 16. Leaf Life Span And Nutrient Resorption As Determinants Of Plant Nutrient Conservation In Temperate-Arctic Regions 17. Leaf Structure And Defence Control Litter Decomposition Rate

Effects of Acute Moisture Stress on Creeping Bentgrass Cuticle Morphology and Associated Effects on Foliar Nitrogen Uptake

Abstract: Foliar fertilization is a common practice to deliver nitrogen (N) to turfgrasses. The mechanisms of foliar applied nutrient uptake, particularly the effects of the leaf cuticle layer, have not been clearly characterized in turfgrasses. The objectives of this study were to determine the effect of acute moisture stress on the morphological and compositional components of the cuticle and the resulting effect on foliar-applied N absorption. Creeping bentgrass (Agrostis stolonifera L.) was irrigated to return 100% or 50% evapotranspiration rate (ET) for 10 days to examine cuticular modifications resulting from acute moisture stress and foliar N uptake with and without a surfactant. Acute water stress increased the total cuticle wax by 11%, mostly as a result of the compound 1-hexacosanol, and increased crystalloid density creating a rougher leaf surface. The 50% ET treatment significantly reduced recovery of N-labeled urea by 14%, which was attributed to the increased total cuticle wax and crystalloid density making the surface less receptive to foliar applications. The surfactant addition to the urea solution increased N-labeled urea recovery by 21% and absorption of N in 50% ET plants to levels consistent with the 100% ET plants. These results suggest that acute moisture stress modifies the cuticle wax load and morphology, thereby hindering foliar absorption; however, a surfactant addition can help to mitigate this effect and increase absorption of N. Drought is a major environmental stress worldwide resulting in decreased plant productivity and diminished plant health. Climate model predicts this to become a more severe problem in the future (Farooq et al., 2012). Drought stress causes cellular dehydration, loss of turgor pressure, and ion toxicity (Bartels and Sunkar, 2005). Plants’ protective responses to water deficiency can include stomatal closure to reduce transpiration (Sharp and Davies, 1989), leaf rolling/orientation to reduce water loss and heat exposure (Kao and Forseth, 1992), and osmotic adjustment to reduce water potential (Delauney and Verma, 1993). In addition to these drought tolerance strategies, cuticle augmentation in response to water deficit has been well documented in a number of plant species, specifically cotton (Gossypium hirsutum L.) (Bondada et al., 1996), Arabidopsis [Arabidopsis thaliana (L.) Heynh.] (Kosma et al., 2009), tree tobacco (nicotiana glauca L.) (Cameron et al., 2006), soybeans [Glycine max (L.) Merr.] (Kim et al., 2007a), sesame (Sesamum indicum L.) (Kim et al., 2007b), rose (Rosa ·hybrids) (Jenks et al., 2001), citrus (Bondada et al., 2001), and peanut (Arachis hypogaea L.) (Samdur et al., 2003). The plant cuticle is a continuous extracellular membrane located on the above-ground organs of most higher plants. Only roots and secondary plant tissue as well as some mosses are devoid of this protective barrier (Koch and Ensikat, 2008). The main function of the cuticle is to protect against uncontrolled water loss to the atmosphere through transpiration (Burghardt and Riederer, 2006; Cameron et al., 2006; Riederer and Schreiber, 2001). Secondary characteristics of the cuticle include antiadhesive properties, repelling water, particles, pathogens, and other molecules, which could hinder the uptake of foliar applications of nutrients and pesticides in an agricultural system (Bargel et al., 2006; Koch et al., 2008). The plant cuticle is comprised of two main portions: the cutin, which provides structure, and waxes, which provide protective functions to the plant. Many of the protective functions of the cuticle, especially repellency, can be attributed to the cuticular and epicuticular waxes that develop on the plant surface. The chemical composition of cuticular waxes is a mixture of aliphatic and aromatic components comprised of various combinations of long chain alkanes, fatty acids, primary and secondary alcohols, aldehydes, and ketones, the proportions of which are dependent on species, developmental stage, and organ (Bargel et al., 2006; Jetter et al., 2006; Riederer and Markstadter, 1996). Epicuticular waxes form thin two-dimensional films and/or three-dimensional structures, depending on chemical composition (Koch et al., 2008). Crystalloids are common threedimensional structures and are characterized as granules, plates, platelets, rodlets, threads, and tubules (Barthlott et al., 1998; Jeffree, 2006). The three-dimensional structures add roughness to the cuticle making it more hydrophobic to foliar applications. Foliar fertilization is widespread in turfgrass maintenance programs because of the labor efficiency and cost-effectiveness resulting from the ability to tank-mix and apply the fertilizer concurrently with additional chemicals. Low-rate application of nutrients to turfgrasses in standard intervals promotes uniform growth that increases playability and aesthetics (Bowman, 2003). Increased canopy color, leaf N concentration, and leaf micronutrient concentrations were reported from creeping bentgrass (Agrostis stonlonifera L.) fertilized frequently using liquid solutions (Schlossberg and Schmidt, 2007). However, the combination of liquid and granular fertilizers provides the best turfgrass quality and reduces total fertilizer input (Totten, 2006; Totten et al., 2008). Minimal N losses from volatilization were documented on creeping bentgrass and hybrid bermudagrass [Cynodon dactylon (L.) Pers. · C. transvaalensis Burtt Davy cv. TifEagle] putting greens applied with foliar urea applications, providing evidence of lower environmental impact by foliar fertilization (Stiegler et al., 2011). Nitrogen absorption with various N sources and factors affecting uptake have been studied on various species in the past. Stiegler et al. (2013) found N-labeled urea uptake was superior to other tested N sources, where absorptions levels ranged from 31% to 56% Received for publication 18 Aug. 2014. Accepted for publication 21 Oct. 2014. We thank Carolinas Golf Course Superintendents Association for financial support of this project. Also we thank the Clemson Electron Microscopy Laboratory for scanning electron microscopy training and assistance. We also thank Dr. Melissa Riley for her help with cuticle methodology and analysis. We appreciate the internal reviewers for their input and suggestions and thanks for Drs. Jeff Atkinson and Bob Cross for their reviews of the manuscript. To whom reprint requests should be addressed; e-mail haibol@clemson.edu. 1582 HORTSCIENCE VOL. 49(12) DECEMBER 2014 of N sources applied after 8 h. Absorption of N-labeled urea was variable through summer months ranging from 36% to 69% on a creeping bentgrass putting green, which it was suggested could partly have been associated with increased cuticle wax loads (Stiegler et al., 2011). In ryegrass (Lolim perenne L.), foliar-applied N-labeled urea was found to be absorbed by 30.3% and 53.1% by new and old leaves after 48 h, respectively. A significant negative relationship was found with urea uptake and epicuticular wax amounts in citrus leaves and cotton (Bondada et al., 1997, 2001). Aqueous pores (greater than 1 nm) have been demonstrated on plant cuticles and provide entry of water and small molecules into the plant (Schönherr, 2006). There is also evidence of a stomatal pathway for the uptake of foliar-applied solutions. Eichert and Goldbach (2008) found significant differences in N uptake with stomatal aperture and stomatous vs. astomatous leaf surfaces, indicating the role of stomata in foliar uptake. The use of adjuvants has also been demonstrated to increase the uptake of foliar-applied chemicals in several plant species under various environmental conditions (Fernandez et al., 2006; Liu, 2004; Neal et al., 1990). For example, surfactant added to potassium nitrate applications increased potassium content in cotton leaves compared with applications with water alone (Howard et al., 1998; Howard and Gwathmey, 1994). Rawluk et al. (2000) documented a 25% increase in N recovery when a nonionic surfactant was added to foliar applications of N-labeled urea in wheat (Triticum aestivum L.). Surfactant added to C-labeled glyphosate applied to barnyardgrass increased the uptake, movement, and herbicide activity (Kirkwood et al., 2000). The addition of adjuvants has become a common practice to increase uptake and reduce losses of foliar-applied fertilizers and pesticides (Wang and Liu, 2007). Creeping bentgrass is the most widely used turfgrass species for putting greens. There is currently a lack of research examining the influence of water stress to the cuticle layer within the species. Data are also lacking to determine if morphological or compositional changes in the cuticle from acute moisture stress influence foliar N uptake and if added surfactant can amend those changes. The objectives of this study were to 1) determine creeping bentgrass cuticle total wax, chemical composition, and morphology; 2) determine the influence of drought stress on creeping bentgrass cuticle total wax, chemical composition, and morphology; and 3) quantify foliar absorption of N-labeled urea with and without a surfactant. Materials and Methods Experimental units. This study was conducted in a growth room at The Clemson University Greenhouse Facilities, Clemson, SC. A mixture of 50:50 seed established (in 2010) ‘A1-A4’ creeping bentgrass putting green plugs (51.61 cm) were harvested from the nursery green at Thornblade Country Club, Greenville, SC, on 4 Apr. 2011 and 2 June 2011, washed thoroughly to remove sand and organic matter from the root zone, and roots cut to 10 cm. Plants were transplanted into 51.61-cm diameter · 18.41-cm depth plastic pots (Elite 300 series) with free drainage, an 85:15 (sand:peat) root zone mixture, and placed in the growth room. The average temperature and relative humidity were 21 C and 31%, respectively, under a 12-h photoperiod with 350 to 450 mmol·m·s photosynthetically active radiation at canop