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Rhopalosiphum padi L., carrying barley yellow dwarf virus, reduced yields of dry forage, protein, cell wall constituents, and total nonstructural carbohydrates of ‘Victory’ oats and ‘Betzes’ barley. The viruliferous aphids reduced heights of barley and oats, the leaf width of oats, and the number of tillers of barley.

The relationship between leaf rigidity and leaf anatomy was examined in genotypes of Lolium perenne cv. S321. Significant relationships were found between frequency of structural units per mm of leaf width and leaf rigidity. However, in cross section no relationship existed between the relative proportions of leaf tissues and leaf rigidity. The plant-breeding implications of these results are briefly discussed.

The purpose of this research was to identify the most desirable verities adopted in different environmental conditions of the country. Five garlic advance line; NARC Garlic-1, NARC Garlic-3, NARC Garlic-4, NARC Garlic-5 along with ‘Lehsan Gulabi’ as check were evaluated at different locations along with NARC, Islamabad. Different morphological parameters; plant height, plant girth, leaf number per plant and leaf width were studied at four different growth stages. NARC Garlic-1 performed better as compared other advance lines and control tested.

This chapter describes the seasonal course of energy exchange between the vegetation and the environment, with an emphasis on the partitioning of solar irradiance. The chapter also discusses the effect of plant form on energy exchange and microclimate in relation to the climatic selection of similar plant forms in mediterranean type regions.

Leaf length divided by leaf width, (L/W), was studied as a criterion for differentiating between nucellar and zygotic citrus seedlings. Progeny of crosses of the variety ‘King’ as a seedparent (known to produce both nucellar and zygotic seedlings) fell into two classes: one with L/W similar to ‘King’ and the other midway between ‘King’ and the pollen parent. In several zygotic seedling populations, population means were intermediate between those of the parents. L/W can be an effective criterion for differentiating between nucellar and zygotic citrus seedlings where the parents differ appreciably.

The first leaf of a grass seedling is normally folded in the form of a scroll inside the coleoptile (Duval-Jouve, 1875). In light-grown plants the leaf unrolls as it emerges from the tip of the coleoptile. When grass seedlings are grown in the dark unrolling does not occur. Unrolling of the leaf is due to differential cell expansion largely within the mesophyll (Burstrom, 1942). Dark-grown leaves are roughly circular in cross-section with the margins considerably overlapping each other. When unrolling occurs, the diameter of the cross-section increases and it bears a weakly sigmoidal relationship to the length of the inner arc of the leaf (Virgin, 1962). However, this lack of linearity does not seriously impair quantitative estimates of the degree of unrolling based on measurements of the projected leaf width. Virgin (1962) determined the action spectrum for light-induced unrolling of the first leaf of wheat seedlings and found it to be a process promoted by red light (c. 660 nm), the promoting effect being nullified by far-red illumination (c.730 nm). This evidence, which we and others (e.g. Wagne, 1964, 1965) have extended to barley seedlings, identifies the pigment system involved as phytochrome. A considerable number of morphogenetic phenomena (Mohr, 1969) including the unbending of the plumular hook of dark-grown legume seedlings, a process analogous in some ways to grass leaf unrolling, are known to be mediated by light absorbed in phytochrome. Most of these responses are developmental events involving irreversible steps in differentiation.

Photomorphogenesis in the barley leaf is characterised by an increased synthesis of chlorophyll and an associated increase in leaf width. These changes are accompanied by an increased capacity for RNA and protein synthesis. We have previously demonstrated that photoinduced unrolling can be enhanced by GA and, furthermore, this growth regulator can induce unrolling of segments maintained in the dark. ABA prevents photoinduced unrolling (Poulson and Beevers 1970). In view of the light-induced changes in RNA metabolism of barley leaf segments (Poulson and Beevers 1970) it was of interest to determine whether the hormonal treatments which influenced unrolling affected the pattern of RNA synthesis of the segments.

Purpose To quantify the contribution of penumbra in the improvement of healthy tissue sparing at reduced source-to-axis distance (SAD) for simple spherical target and different prescription isodoses (PI). Method A TPS-independent method was used to estimate three-dimensional (3D) dose distribution for stereotactic treatment of spherical targets of 0.5 cm radius based on single beam two-dimensional (2D) film dosimetry measurements. 1 cm target constitutes the worst case for the conformation with standard Multi-Leaf Collimator (MLC) with 0.5 cm leaf width. The measured 2D transverse dose cross-sections and the profiles in leaf and jaw directions were used to calculate radial dose distribution from isotropic beam arrangement, for both quadratic and circular beam openings, respectively. The results were compared for standard (100 cm) and reduced SAD 70 and 55 cm for different PI. Results For practical reduction of SAD using quadratic openings, the improvement of healthy tissue sparing (HTS) at distances up to 3 times the PTV radius was at least 6%-12%; gradient indices (GI) were reduced by 3-39% for PI between 40% and 90%. Except for PI of 80% and 90%, quadratic apertures at SAD 70 cm improved the HTS by up to 20% compared to circular openings at 100 cm or were at least equivalent; GI were 3%-33% lower for reduced SAD in the PI range 40%-70%. For PI = 80% and 90% the results depend on the circular collimator model. Conclusion Stereotactic treatments of spherical targets delivered at reduced SAD of 70 or 55 cm using MLC spare healthy tissue around the target at least as good as treatments at SAD 100 cm using circular collimators. The steeper beam penumbra at reduced SAD seems to be as important as perfect target conformity. The authors argue therefore that the beam penumbra width should be addressed in the stereotactic studies.

The effect of Ca, Cu and Zn ions on plant recovery and disease severity following infection of huanglongbing disease was carried out at a commercial citrus orchards belonging to Lembaga Pertubuhan Peladang (LPP) Terengganu, situated at Durian Mentangau, Dungun, Terengganu. Application of Zn or Cu ions in combination with Ca was able to delay disease incidence and severity of hunglongbing disease. These treatments (C/Ca/Cu and C/Ca/Zn) also showed slightly reduction of AUDPC value on infected citrus trees. In general, analysis of macronutrients and micronutrients content in citrus leaves showed significantly different at the beginning of the study (0 to 6 months after treatment) but no significant different were observed at the end of the study period (6-9 months after treatment) as noted on Mg, P, Ca and Zn analysis. Results for specific leaf area showed no significant different among treatment as observed in leaf area, total leaf length and total leaf width. However, specific leaf area was increased gradually in all treatments over the period of the study. The overall results of field trial showed that infected citrus trees treated with combination of Ca and Zn ions at 600 and 10 ppm, respectively resulted in significant increase (P≤0.05) in terms of fruit production and total soluble solid (TSS) content only. Key words: Huanglongbing, candidatus liberibacter asiaticus, field assessment, micronutrients and macronutrients.

Background To investigate the effect of multi-leaf collimators (MLCs) with leaf width of 1.25 mm on the plan quality of volumetric modulated arc therapy (VMAT) for prostate cancer. Methods A total of 20 patients with prostate cancer were retrospectively selected. Using a high definition MLC (HD MLC), primary and boost VMAT plans with two full arcs were generated for each patient (original plan). After that, by shifting the isocenter position of the 2nd arc by 1.25 mm in the cranio-caudal direction, we simulated fluences made with MLCs with leaf width of 1.25 mm. After shifting, primary and boost plans were generated for each patient (shifted plan). A sum plan was generated by summation of the primary and boost plan for each patient. Dose-volumetric parameters were calculated and compared. Results Both the homogeneity index (HI) and conformity index (CI) of the shifted plans were better than those of the original plans in primary plans (HI = 0.065 vs. 0.059 with p

The aim of this study was to investigate the impact of multileaf collimator width (MLC‐W) on intraprostatic dose painting plans for prostate cancer. Prostate cancer maps based on the histopathological findings were superimposed onto simulation CT images. Clinical target volume (CTV) 1 was defined as the prostate and the base of the seminal vesicles, and CTV2 was defined as the dominant intraprostatic lesions. Planning target volume (PTV) 1 and PTV2 were delineated by adding 5 mm margins to CTV1 and CTV2, respectively. For each case, two dose painting plans were created to deliver 74 Gy to PTV1 and 84 Gy to PTV2 with dynamic multileaf collimator technique using two different MLCs: m3 (MLC‐W: 3 mm) and Millennium (5 mm). Plans were evaluated by comparing the conformation number (CN), a quantity that defines the degree of conformality. The CNs for plans using the m3 and Millennium were 0.68 and 0.67 for PTV1 and 0.59 and 0.58 for PTV2, respectively. The CNs tended to be higher for a thinner leaf width (p

Width-to-length ratios of upper stem leaves ofLasallea novaeangliae andL. oblongifolia were determined from herbarium specimens and field collections. No distinct subgroups based on suchratios were found in either species. InL. novaeangliae the curve of the ratio versus number of individuals was skewed toward the narrow-leaf range. This phenomenon was present but less pronounced inL. oblongifolia. The histogram of leaf ratios forL. novaeangliae was somewhat weakly bimodal, suggesting a possible broad-leaf race, which has not been recognized nomenclaturally. The absence of bimodality in the histogram of leaf ratios forL. oblongifolia indicates the need to place Shinners’ narrow-leaved varietyangustatus in synonymy. Other traits such as height, degree of branching and the nature of the pubescence were also found to be of no significance. Slight geographic trends in leaf width occur in both species. No real evidence was found for nomenclaturally recognizing any eastern variant in either species. Thus, Shinners’ var.orientis is not recognized inL. oblongifolia either.

Weissia sharpii Anders. & Lemmon is a recently described species endemic to the Southern Appalachian-Ozarkian region. It was distinguished from the more widespread species, W. controversa Hedw., on the basis of its diploid gametophytes, restricted habitat in cedar glades, and several morphological features of the gametophytes. An experiment was performed in which two populations each of W. sharpii and W. controversa were grown reciprocally on soil from each other's native habitats, and twelve morphological characters were measured. Soil type had virtually no effect on the expression of any of the characters. An analysis of variance indicates that the species differ significantly in leaf length-width ratio, upper leaf width, and in the width of the gap between involuted leaf margins. These morphological discontinuities, combined with differences in chro- mosome number and ecology, indicate that W. sharpii and W. controversa should be treated as separate species. Weissia controversa exhibited a greater degree of variation between populations than did W. sharpii when both were grown experimentally. This is in agreement with the relative variability of W. controversa in nature. Experimental studies on the plasticity of morphological characters in mosses and liverworts are reviewed. Weissia Hedw. is one of about sixty-five gen- era in the moss family, Pottiaceae. In their checklist of North American mosses, Crum et al. (1973) credited eight species of Weissia as occurring on this continent, but only one, W.

On the basis of chromosome numbers from more than 1,000 individuals of Claytonia virginica L. (Portulacaceae) throughout its range, a complex evolution of major cytotypes is discussed in relation to distribution and morphology. Chromosomal diversity is thought to have evolved from a base of n 6 by hyperaneuploidy to n 7 and 8 with each race giving rise to widespread and dominant primary tetraploids (n 12, 14, 16). These in turn, and largely by hypoaneuploidy, formed many secondary tetraploid races, the most significant of which are n = 11 and 15. Higher polyploids from 6x to 12x where x = 6, and 6x and 8x where x = 7 are also discussed. Infraspecific phylogeny is compared with data for two allied species, C. caroliniana Michx. and C. lanceolata Pursh, which show striking parallels with C. virginica in chromosomal evolution. By one morphological character, leaf width, the cytotypes separate into two groups, not along diploid vs. polypoid lines, but rather a narrow-leafed var. acutiflora DC. with n = 6, 7, 12?, and 14? and a broad-leafed var. virginica with n = 8 and 16?. From collections made throughout eastern North America over 1,000 plants of Claytonia virginica L. (Portulacaceae) have been examined chromosomally. With the exception of Rothwell (1959) earlier studies have been limited in scope although all have made a substantial contribution to a cytogeographic understanding of the species (Bell, 1965; Davis & Bowmer, 1966; Lewis, 1959, 1962, 1967; Lewis et al., 1962, 1967; Rothwell & Kump, 1965). While these studies illustrated a wide diversity of chromosome number for C. virginica (2n12 to ca 191) none was extensive enough to indicate total distribution of all major cytotypes; rather only for a few from very limited areas, viz. dominance of x 7 in eastern Texas (Lewis, 1962), x = 8 in Indiana (Rothwell, 1959), and n= 12 and 15 in the St. Louis, Missouri area (Lewis et al., 1967). We shall attempt with our additional data to present the distribution of cytotypes occuring in the eastern half of the continent and to suggest their probable evolution. Cytogeography and evolution of C. virginica will be compared with several allied species as well as briefly with the primitive species of Claytonia. In addition gross morphological diversity will be correlated with the various cytotypes and discussed in relation to distribution. Cytological procedures followed those of Lewis (1962) and voucher specimens for each population were collected and are housed in the Missouri Botanical Garden herbarium (MO). 'Senior Fellow and Research Associates, Center for the Biology of Natural Systems, supported by Public Health Grant No. 1 P10 ES 00139-01 ERT. ANN. MISSOURI BOT. GARD. 54(2): 153-171, 1967. This content downloaded from 207.46.13.113 on Wed, 05 Oct 2016 04:20:10 UTC All use subject to http://about.jstor.org/terms [VOL. 54 154 ANNALS OF THE MISSOURI BOTANICAL GARDEN