Hairy Leaf Research Articles

Evaporation and coverage area of pesticide droplets on hairy and waxy leaves

The fate of pesticide droplets on leaves is significantly influenced by the fine structures found on leaf surfaces. Evaporation times and the maximum coverage areas of single droplets (246, 343, 575, 762, and 886 μm) on hairy and waxy geranium leaf surfaces were determined under controlled conditions. Stereoscopic sequential images of the droplet evaporation processes were taken for five droplet sizes, three relative humidity (RH) conditions and 13 different sprays. The sprays were combinations of water, a non-ionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, a fungicide and three insecticides. The evaporation time and maximum coverage area of droplets were significantly changed by adding the surfactant or drift retardant to the sprays, but not by adding fungicide or insecticide. Droplet evaporation times on waxy leaves were longer than those on hairy leaves. Evaporation times increased exponentially as droplet diameter and RH increased with limited variability of regression coefficients independent of spray type and leaf surface. The maximum coverage area of droplets also increased exponentially as droplet diameter increased but it was not significantly affected by RH. On the waxy geranium leaf surfaces, the coverage area of pesticide droplets decreased throughout the evaporating process and at all RH conditions, while, on hairy leaf surfaces for the same size droplets, and at the same RH conditions, the coverage area continued to spread until evaporation was nearly completed. Given that the duration of evaporation time and the extent of the coverage area affect pesticide distribution on waxy or hairy leaves, recommendations for pesticide dosage and spray methods should be taken into account for different leaf surfaces to obtain the optimum biological effect and reduced pesticide use.

Biology and natural history of Caladenia

The genus Caladenia comprises species that exhibit remarkable consistency in terms of growth form and phenological patterns. All taxa are herbaceous perennials, with the shoot arising annually from a single, usually spheroid, tuber and producing a single, hairy leaf. The tuber is annually replaced either side-by-side with the parent tuber or terminating a descending structure known as a dropper. The dropper is a depth-seeking mechanism that enables placement of the tuber at depth in the soil as a means to avoid predation by surface-foraging native mammals or away from the high temperatures and desiccating conditions during summer dormancy. The 3--5 attenuated roots produced at the junction between the tuber and shoot and produced late in the growing cycle and devoid of mycorrhiza suggest their functional significance may relate to water uptake. Mycorrhizal endophytes are confined to a hypertrophic stem region at the soil surface (collar) subtending the leaf that positions the collar directly in the organically rich zone at the soil surface. This morphology is a unique characteristic of several Australasian orchids in the tribe Diuridae. Mycorrhizal infection occurs rapidly, with maximum colonisation in concert with the onset of breaking rains. Pelotons are restricted to cortical cells, with fully developed pelotons throughout infected tissues within a week or so of soil wetting. Infection occurs as a ‘once-off’ event, with little evidence of secondary infection later in the growth cycle and no evidence of peloton digestion. Some taxa utilise vegetative propagation, often leading to localised clustering as for taxa in the ‘filamentosa’ complex or, extensive clonal mats as found in Caladenia flava and C. latifolia where daughter tubers are produced at the end of extending horizontal outgrowths. For the majority of taxa, plants remain dry-season (summer) dormant from a few months up to 7 months for arid-zone taxa, with shoot emergence from the tuber of temperate species thought to occur in response to a drop in the mean minimum temperature. Pollination biology of Caladenia is apparently through a process of deception, either as food or sexual mimics, with some taxa engaging in self-pollination. Here we review the natural history of Caladenia and acknowledge that much of our understanding is based on assumptions of the biology of terrestrial orchids in general and emphasise areas of research and biological enquiry that will be critical in the development of an effective conservation program for the genus.

DArT markers: diversity analyses, genomes comparison, mapping and integration with SSR markers in Triticum monococcum

BackgroundTriticum monococcum (2n = 2x = 14) is an ancient diploid wheat with many useful traits and is used as a model for wheat gene discovery. DArT (Diversity Arrays Technology) employs a hybridisation-based approach to type thousands of genomic loci in parallel. DArT markers were developed for T. monococcum to assess genetic diversity, compare relationships with hexaploid genomes, and construct a genetic linkage map integrating DArT and microsatellite markers.ResultsA DArT array, consisting of 2304 hexaploid wheat, 1536 tetraploid wheat, 1536 T. monococcum as well as 1536 T. boeoticum representative genomic clones, was used to fingerprint 16 T. monococcum accessions of diverse geographical origins. In total, 846 polymorphic DArT markers were identified, of which 317 were of T. monococcum origin, 246 of hexaploid, 157 of tetraploid, and 126 of T. boeoticum genomes. The fingerprinting data indicated that the geographic origin of T. monococcum accessions was partially correlated with their genetic variation. DArT markers could also well distinguish the genetic differences amongst a panel of 23 hexaploid wheat and nine T. monococcum genomes. For the first time, 274 DArT markers were integrated with 82 simple sequence repeat (SSR) and two morphological trait loci in a genetic map spanning 1062.72 cM in T. monococcum. Six chromosomes were represented by single linkage groups, and chromosome 4Am was formed by three linkage groups. The DArT and SSR genetic loci tended to form independent clusters along the chromosomes. Segregation distortion was observed for one third of the DArT loci. The Ba (black awn) locus was refined to a 23.2 cM region between the DArT marker locus wPt-2584 and the microsatellite locus Xgwmd33 on 1Am; and the Hl (hairy leaf) locus to a 4.0 cM region between DArT loci 376589 and 469591 on 5Am.ConclusionDArT is a rapid and efficient approach to develop many new molecular markers for genetic studies in T. monococcum. The constructed genetic linkage map will facilitate localisation and map-based cloning of genes of interest, comparative mapping as well as genome organisation and evolution studies between this ancient diploid species and other crops.

Molecular mapping of genes determining hairy leaf character in common wheat with respect to other species of the Triticeae

Two major genes controlling leaf pubescence were mapped on chromosomes 4BL (Hl1) and 7BS (Hl2 Aesp ) in wheat (Saratovskaya 29) and a wheat/Aegilops introgression line (102/00I), respectively, together with quantitative trait loci (QTLs) determining hairiness of the leaf margin (QHl.ipk-4B, QHl.ipk-4D) and auricle (QPa.ipk-4B, QPa.ipk-4D) on the long arms of chromosomes 4B and 4D, respectively. The QTLs on chromosome 4D were contributed by a synthetic wheat and, therefore, originated from Aegilops tauschii. The homoeologous group 4 wheat/A. tauschii genes/QTLs detected in the present study were aligned with the barley pubescence genes Hln/Hsh and Hs b and the hairy peduncle rye gene Hp1. The locus seems to be pleiotropically responsible for the pubescence of different plant organs in different species of the Triticeae. Another homoeologous series may be present on the short arms of the homoeologous group 7 chromosomes, based on the results of an allelic test cross between the Chinese local cultivar Hong-mang-mai carrying Hl2 and the wheat/Aegilops speltoides introgression line 102/00I.

Adaptations of two specialist herbivores to movement on the hairy leaf surface of their host, Solanum guaraniticum Hassl (Solanaceae)

Plant trichomes can difficult the attachment and movement of small insects. Here, we examine the hypothesis that the success on the use of densely haired hosts by two cassidine species is determined by differential morphology and behavior. Larvae of Gratiana graminea (Klug, 1829) and Gratiana conformis (Boheman, 1854) move on the leaf surface of their host, Solanum guaraniticum Hassl by anchoring their tarsungulus on the trichome rays or by inserting the tarsungulus tip directly into epidermis. This kind of movement is only possible due to a similar tarsungulus shape among the species. Tarsungulus growth pattern is also similar between species, being relatively small on the posterior aperture, matching the diameter of the host plant trichome rays. The tarsungulus shape associated with differences on ontogenetic growth and attachment pattern allow these two Cassidinae larvae to efficiently move on the pubescent leaf surface of their host.

Oviposition preference and larval survival of Chilo partellus (Lepidoptera: Pyralidae) on Napier grass (Pennisetum purpureum) trap crops

Bioassays were conducted to identify varieties of Napier grass (Pennisetum purpureum) that may be used as trap crops for the gramineous stem-borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae). Oviposition preference was determined in two-choice tests with maize and Napier grass in the laboratory while larval survival was determined under greenhouse conditions. Twenty-one different Napier varieties and P. purpureum × P. glaucum hybrids were evaluated and compared to maize in these bioassays. The varieties were collected from nurseries, from the wild and from farmers using them as a source of animal fodder. Results from two-choice tests indicated that Napier grasses were highly preferred for oviposition by C. partellus moths. However, Napier grasses were poor larval hosts, and a rapid decline in larval numbers was observed during the first week after egg hatch. Larval survival on maize was significantly higher than on Napier grass where virtually no larvae survived. The evaluated Napier grass varieties therefore have the characteristics required of trap crops. Preference for oviposition on hairy leaf surfaces of Napier grass instead of maize was most likely influenced by leaf volatiles since oviposition preference was negatively correlated to leaf hairiness.

Oviposition behaviour of ‘Cnephasia’ jactatana Walker (Lepidoptera: Tortricidae) on kiwifruit

The oviposition behaviour of ‘Cnephasia’ jactatana Walker, a pest of Hayward kiwifruit, was investigated in the laboratory. Almost 95% of eggs were deposited on the upper side of leaves with the remainder on twigs. No eggs were laid on fruits or flowers. When given a choice, ‘C.’ jactatana laid significantly more eggs on mature than on young leaves of Hayward (green) and laid significantly more and larger egg masses on Hayward than on Hort16A (gold) leaves. Females preferred a smooth to hairy leaf surface for oviposition.

Moving on hairy surfaces: modifications of Gratiana spadicea larval legs to attach on its host plant Solanum sisymbriifolium

AbstractBoth larvae and adults of Gratiana spadicea (Klug) (Coleoptera: Chrysomelidae: Cassidinae) feed exclusively on leaves of Solanum sisymbriifolium Lamarck (Solanaceae), which have simple and stellate trichomes. The simple trichomes can be non‐glandular or glandular. The stellate trichomes present a long central ray that secretes a viscous exudate when broken. Trichome effects on movement of G. spadicea larvae were evaluated in the laboratory. Larval speed on intact petioles of S. sisymbriifolium was compared to those where the exudates and/or stellate trichomes were removed. Exudates had no effect on larval speed. Stellate trichomes mechanically slowed down first instar movement. Gratiana spadicea larval legs have a modified distal portion, the tarsungulus, whose rounded aperture shape matches that of the cylindrical pointed rays of S. sisymbriifolium stellate trichomes. The first three instars anchor the tarsungulus to the trichome rays, and get both attachment to the leaf surface and support to body impulsion. Morphological comparisons showed that the legs in the first larval instars are shorter than the central ray of the stellate trichome, so larvae have to walk above them. Fifth instar larvae have longer legs and walk by inserting the sharp tip of their tarsungulus directly into the leaf epidermis. The dimensions of the tarsungulus aperture vary in such a way that it can clasp every thickness of trichome ray for any larval instar. Contrary to other tarsungulus portions and larval body features, where growth is allometric, growth of the tarsungulus aperture is isometric throughout the larval stage. Thus, it is suggested that this G. spadicea leg structure is adapted for moving on hairy leaf surface of S. sisymbriifolium.

Chromosome arm location of the gene controlling leaf pubescence of a Chinese local wheat cultivar ‘Hong-mang-mai’

The inheritance of the leaf pubescence character of a Chinese local wheat cultivar ‘Hon-mang-mai’ was investigated by monosomic and telosomic analyses. Leaf pubescence was evaluated by observation of the adaxial side of the penultimate leaf of adult plants. F1 hybrids of ‘Hong-mang-mai’ with a non-pubescent cultivar ‘Chinese Spring’ had leaf pubescence, but its density was about a half of that of ‘Hong-mang-mai’. In the F2 generation, the segregation ratio of pubescent to non-pubescent plants fitted a ratio of 3: 1, suggesting that leaf pubescence was controlled by one dominant gene. Monosomic analysis revealed that the gene for pubescence is located on chromosome 7B. Telosomic analysis showed that the gene is located on the short arm of chromosome 7B with a distance of 14.3%from the centromere. This gene is not allelic with the previously reported hairy leaf gene Hl on chromosome 4B, and therefore, is designated Hl2, hairy leaf 2.

RFLP mapping of a gene for hairy leaf sheath using a recombinant line from Hordeum vulgare L. ×Hordeum bulbosum L. cross

A gene conditioning hairy leaf sheath character, which was derived from Hordeum bulbosum and designated Hsb, was mapped using a cross between Hordeum vulgare and a H. vulgare/H. bulbosum recombinant line. The Hsb locus was tagged relative to eight RFLP markers detecting three loci on the distal part of chromosome 4HL. The map position suggests that Hsb of H. bulbosum is homoeologous to the gene Hp1 of rye (Secale cereale), which pleiotropically governs the traits hairy leaf sheath and hairy peduncle. It is proposed that the recombination break point between H. vulgare and H. bulbosum chromosomes occured at a position homoeologous compared with the 4L/5L translocation in Triticeae genomes, and may reflect a hot spot for chromosome breakage.Key words: Hordeum vulgare, Hordeum bulbosum, comparative mapping, hairy leaf sheath, RFLP.

Inheritance in hexaploid wheat of genes for hairy auricles and hairy leaf sheath derived from Aegilops tauschii Coss.

Inheritance of genes for hairy auricles and hairy leaf sheath of Ae. tauschii in hexaploid wheat backgrounds (synthetic hexaploid wheat and common wheat varieties) was analyzed. The results indicated that hairy auricles and hairy leaf sheath of Ae. tauschii can be transferred and are expressed in hexaploid wheat. In a synthetic hexaploid wheat (‘Ae. tauschii’ 188) hairy auricles was proved to be controlled by a single dominant gene derived from Ae. tauschii, which was different from the Pa gene located on chromosome 4BS of common wheat. The hairy leaf sheath phenotype of ‘Altar 84/Ae. tauschii 188’ was also controlled by a single dominant gene derived from Ae. tauschii, which is obviously different from the Hls gene in T. dicoccoides. We suggest to designate the Ae. tauschii genes for hairy auricles and hairy leaf sheath as Pa2 and Hls2, respectively; such genes could be used as useful genetic markers in common wheat.

A consensus linkage map of rye (Secale cereale L.) including 374 RFLPs, 24 isozymes and 15 gene loci

Consensus linkage maps were constructed for all seven rye chromosomes using 12 basic RFLP maps. The maps presented contain a total of 413 markers. The number of markers per chromosome varies from 41 (chromosome 3R) to 83 (chromosome 1R). In addition to 374 RFLP and 24 isozyme markers 15 gene loci were incorporated, determining the traits reduced plant height, self fertility, male sterility restoration, vernalization response, resistance against powdery mildew, chlorophyll deficiency, hairy leaf sheath, hairy peduncle, waxy endosperm, waxless plant and absence of ligules. The maps presented allow the selection of markers for the fine mapping of certain regions of the rye genome. In terms of the known chromosomal rearrangements within the Triticeae its utilization can also be extended for mapping in wheat and barley.

A revision of <i>Ledebouria</i>(Hyacinthaceae) in South Africa. 2. Two new species, <i>L. crispa</i> and <i>L. parvifolia</i>, and <i>L. macowanii re-instated

Two endemic Ledebouria Roth species are described with notes, diagnostic characters, distributions and alliances. L. crispa appears to be allied to L. socialis (Baker) Jessop with which it shares densely gregarious, epigeal bulbs and L. undulata (Jacq.) Jessop of the Northern and Western Cape which shares crispate leaf margins. L parvifolia is endemic to Mpumalanga (eastern Transvaal) and was recorded from a single locality near Graskop; it differs from L. cooperi (Hook.f.)Jessop in having hairy upper leaf surfaces. L macowanii (Baker) S.Venter is re instated; it is distinguished from L. cooperi by its tightly clasping bulb scales and single cataphyll.

New Taxa, New Combinations, and Observations in Kengyilia (Poaceae: Triticeae)

A new species is described and five new combinations are made in Kengyilia. The new taxa are Kengyilia eremopyroides and K batalinii var. villosissima. Kengyilia longiglumis and K nana are reduced to K. alatavica var. longiglumis and K. nana to K. batalinii var. nana, respectively. Roegneria carinata, Elytrigia kryloviana, and Elytrigia pulcherrima are transferred to Kengyilia as K carinata, K. kryloviana, and K pulcherrima, respectively. We first described Kengyilia Yen & J. L. Yang in 1990 (Yen & Yang, 1990) and soon afterward added a new species to it (Baum et al., 1991). Subsequently, we provided a synopsis and key to the 16 species of the genus known to us at the time (Yang et al., 1992). Cai and Cui (1995) have since added two more new species. This genus, now with approximately 20 species, is distributed primarily in west China, with some species found in countries west of China. We recently investigated the taxonomic relationships with and differences between its congeners Roegneria, Elymus, and Agropyron (Baum et al., 1995) and provided a key to identify these four genera. We are currently preparing a taxonomic monograph of Kengyilia. Toward this goal we are searching for type material in different herbaria. A recent visit to the Komarov Botanical Institute, St. Petersburg, Russia, during the summer of 1995, by Yen and Yang was carried out to study type material of Kengyilia. Morphological examinations of specimens, especially type material, led to the conclusion that a number of species in Kengyilia were hitherto misnamed and that other species needed to be incorporated within Kengyilia. The purpose of this paper is to document the new combinations and revisions in Kengyilia resulting from the examinations carried out during the recent visit to LE. MATERIAIS AND METHODS Morphological examinations were performed on herbarium materials, including type collections, from the following herbaria: JSBI, K, LE, NUBD, PE, SAUTI, TK. Characters on these specimens were evaluated for quantitative and qualitative measurements and compared to various pertinent protologues for taxonomic assessment. REsC I Ts--TAxONOMIC( TREATMENTS 1. Kengyilia alatavica (Drobov) J. L. Yang, Yen & Baum var. longiglumis (Keng & S. L. Chen) Yen, J. L. Yang & Baum, comb. nov. Basionym: Roegneria longiglumis Keng & S. L. Chen, Acta Nanking Univ. (Biol.) 1: 83. 1963. Kengyilia longiglumis (Keng & S. L. Chen) Yang, J. L., Yen & Baum, Hereditas 116: 27. 1992. TYPE: China. Gansu, on slopes, alt. 2500 m, July 6 1937, T P Wang No. 7080 (holotype, PE). Figure 1A. Distribution. China: Gansu, Xiahe; Xinjiang, Yecheng, Taxkorgan and between Wuqia and Turugar, on dry slopes and scree, alt. 2500-3340 m. This taxon was known hitherto as K. longiglumis, from the Chinese material that was examined. Our comparative studies proved that K. longiglumis is a taxonomic synonym of K alatavica. The Chinese material is here recognized as a separate variety; it differs from K alatavica var. alatavica by its hairy leaf sheaths and culms, and by the short rounded lodicules (Fig. 1A). The pointed lodicules of the typical variety are shown in Figure lB. 2. Kengyilia batalinii (Krassnov) J. L. Yang, Yen & Baum var. villosissima Roshevitz ex Yen, J. L. Yang & Baum, var. nov. TYPE: Turkestan. Pamir, near Karakuli Lake, July 5 1901 [collector & collection no. unretained] (holotype, LE). Figure 2. NovoN 8: 94-100. 1998. This content downloaded from 207.46.13.193 on Thu, 08 Sep 2016 04:19:38 UTC All use subject to http://about.jstor.org/terms Volume 8, Number 1 1998 Yen et al. New Taxa in Kengyilia 95

Morpho-physiological traits characterizing environmental adaptation of Avena barbata

Seventeen morphological and physiological characteristics of three Avena barbata L. populations from Israel were measured in order to define possible combinations explaining adaptation of these populations to different precipitation, temperature and altitude regimes. Five genotypes from each A. barbata populations were collected from Ashqelon (31°63′N, low annual precipitation), En Hamifraz (32°46′N, high temperature), and Mount Carmel (32°73′N, high altitude), Israel. The behavior of the populations was followed by measuring the morpho-physiological characteristics under well-watered and moderately drought stressed conditions. The experiment was conducted at the Department of Plant Production, University of Helsinki, Finland (60°13′N). The measured traits characterized macro-morphology, transpiration rate, photosynthesis and chloroplast features. The data were subjected to principal component and discriminant analyses and the characteristic combinations that most adequately accounted for the differences among A.barbata populations were established. Differences among the populations were related to adaptation to low water availability and high altitude characterized by special light conditions. The Mount Carmel population (high water availability, high light intensities and increased proportion of UV-light) was characterized by higher tillering, hairy leaf sheaths, high transpiration, high stomatal conductance, slow fluorescence quenching capacity, and less starch granules per chloroplast when compared with populations adapted to lower altitudes. The En Hamifraz population (high mean temperature) was characterized by a high CO2 exchange rate and both En Hamifraz and Ashqelon populations (both adapted to arid conditions) used water sparingly when moderately drought stressed.

RFLP mapping of the dwarfing (Ddw1) and hairy peduncle (Hp) genes on chromosome 5 of rye (Secale cereale L.)

An F2 population was established for mapping the two dominant genes for dwarfness (Ddw1) and hairy peduncle (Hp) on chromosome 5R. The location of both genes was shown to be on the segment of chromosome 5RL which was ancestrally translocated and is homoeologous to Triticeae 4L. Hp cosegregated with the wheat gDNA probe WG199, localised in wheat on chromosomes 5AL, 4BL and 4DL. No segregation was observed between the traits hairy peduncle and hairy leaf sheath. The locus for Ddw1 was found to map distally to Hp/Xwg199 but proximal to the isozyme marker β-amy-R1. The genetical distances were 5.6 cM between Hp/Xwg199 and Ddw1 and ll.ScM between Ddw1 and β-amy-R1, respectively. The map position of Ddw1 suggests that it is homoeologous to the wheat dominant dwarfing gene Rht12, present on chromosome 5AL and linked to β-amy-A1.

Production and identification of three 4Ag(4D) substitution lines of Triticum aestivum — Agropyron: relative transmission rate of alien chromosomes

By crossing fertile nullisomics-4D of common wheat (nullisomics 72180 and 'Tianxuan' no. 15) with three octoploid Agrotriticum lines [partial amphiploids (2n=56) 78829 from the offsprings of wheat with Agropyron intermedium (=Thinopyrum intermedium, 2n=42) and 784 and 7631 from those of wheat with Ag. elongatum (Thinopyrum elongatum, 2n=70)], backcrossing the hybrid with 4D nullisomics as recurrent parent for one to two generations, and then selfing the BC individuals, we obtained three different alien substitution lines, 4Ei (4D), 4Ee(4D) blue grain, and 4Fe(4D) hairy leaf. The F1 hybrids of 784×78829 had the basic chromosome pairing configuration of 27″ + 2', indicating that 784 and 78829 differed by only one pair of chromosomes. This means that Ag. intermedium and Ag. elongatum have a genome (or genomes) in common. The formation of 22″ +12' in the F1 of 784×7631 suggested that there was only one pair of homologous chromosomes of Ag. elongatum in 784 and 7631. Because F1 plants of 7631×78829 generally formed 21″ +14' at metaphase I, the Agropyron genomes in the two octoploid Agrotriticums were presumed to differ from each other. Upon intercrossing the three alien substitution lines, we found that all of the pollen mother cells of the F1 plants had 20″ + 2' or more univalents at metaphase I. We concluded that the three Agropyron chromosomes were not homologous but belonged to the same homoeologous group. These results were confirmed by reciprocal crosses of the three octoploids. The relative transmission rates of 4Ee, 4Fe, 4Ei, 4R and 4D were calculated using blue grain and hairy leaf as genetic markers; these were 4D>4Ee>4Ei, 4Fe>4R. The four alien chromosomes could compensate for the 4D of bread wheat, the substitution lines being vigorous and fertile.

A Rare New Caladenia species from central Victoria, and its relationship with other recently described taxa in south-eastern Australia

Caladenia xanthochila D. et C. Beardsell is a pale yellow orchid related to Caladenia reticulata FitzG. and Caladenia flavovirens G. Carr, but differs in its smaller flowers, early flowering period, small sections of contiguous purple osmophore glands on sepals, short (0–1.3mm) teeth on the labellum margin, short labellum calli, uniformly pale greenish yellow colour, and extremely hairy ovary, stem and leaf. Its closest relative is C. stellata D. Jones from which it differs in having a wholly pale yellow labellum, swollen tips to the column glands, contiguous osmophore glands, mid-lobe of labellum with entire margin or with extremely short blunt calli, labellum more recurved, and longer trichomes on stem and ovary. Caladenia xanthochila is known from only two localities, one near Inglewood, the other at Murtoa, both in Victoria, and is thus on the verge of extinction.

Effects of Mechanical Cleaning on Cotton Fibers

Smooth leaf and hairy leaf Midsouth cottons were processed through minimum, two intermediate, and maximum gin cleanings. Based on fiber measurements after mill cleaning, minimum gin cleaning yielded the best fiber quality ( i.e., length, low short fiber content). Fiber damage as a result of maximum gin cleaning was evident through all levels of mill cleaning. There were also differences in nonlint content as a result of cleaning machinery and cotton varieties.

Morpho‐anatomical adaptations of the endemic species Degenia velebitica (DEG.) HAY

AbstractMorpho‐anatomical investigations of the species Degenia velebitica have shown numerous xeromorphic and heliomorphic adaptations. The most clearly apparent adaptive features are the plant's study hairy leaf covering, compact structure of mesophyll and the preponderance of the palisade tissue as well as the well‐developed vascular system in the leaf and stem. Its survival on very windy screes is also aided by powerful tap‐roots and a dwarf life form with shortened internodes. D. velebitica plays an important role in forming the overgrowth and maintaining vegetation on mediterranean mountain screes of Velebit massif.