Anatomical Properties (anatomical + property)

Distribution by Scientific Domains

Selected Abstracts

Height-related trends in leaf xylem anatomy and shoot hydraulic characteristics in a tall conifer: safety versus efficiency in water transport

D. R. Woodruff
Summary ,,Hydraulic vulnerability of Douglas-fir (Pseudotsuga menziesii) branchlets decreases with height, allowing shoots at greater height to maintain hydraulic conductance (Kshoot) at more negative leaf water potentials (,l). ,,To determine the basis for this trend shoot hydraulic and tracheid anatomical properties of foliage from the tops of Douglas-fir trees were analysed along a height gradient from 5 to 55 m. ,,Values of ,l at which Kshoot was substantially reduced, declined with height by 0.012 Mpa m,1. Maximum Kshoot was reduced by 0.082 mmol m,2 MPa,1 s,1 for every 1 m increase in height. Total tracheid lumen area per needle cross-section, hydraulic mean diameter of leaf tracheid lumens, total number of tracheids per needle cross-section and leaf tracheid length decreased with height by 18.4 m2 m,1, 0.029 m m,1, 0.42 m,1 and 5.3 m m,1, respectively. Tracheid thickness-to-span ratio (tw/b)2 increased with height by 1.04 10,3 m,1 and pit number per tracheid decreased with height by 0.07 m,1. ,,Leaf anatomical adjustments that enhanced the ability to cope with vertical gradients of increasing xylem tension were attained at the expense of reduced water transport capacity and efficiency, possibly contributing to height-related decline in growth of Douglas fir. [source]

Slow development of leaf photosynthesis in an evergreen broad-leaved tree, Castanopsis sieboldii: relationships between leaf anatomical characteristics and photosynthetic rate

S.-I. Miyazawa
ABSTRACT Changes in net photosynthetic rate on a leaf area basis and anatomical properties during leaf development were studied in an evergreen broad-leaved tree, Castanopsis sieboldii and an annual herb, Phaseolus vulgaris. In C. sieboldii, surface area of mesophyll cells facing the intercellular air spaces on a leaf area basis (Smes) was already considerable at the time of full leaf area expansion (FLE). However, surface area of chloroplasts facing the intercellular air spaces on a leaf area basis (Sc), and chlorophyll and Rubisco contents on a leaf area basis increased to attain their maximal values 15,40 d after FLE. In contrast, in P. vulgaris, chloroplast number on a leaf area basis, Sc and Smes at 10 d before FLE were two to three times greater than the steady-state levels attained at around FLE. In C. sieboldii, the internal CO2 transfer conductance (gi) slightly increased for 10 d after FLE but then decreased toward the later stages. Limitation of photosynthesis by gi was only about 10% at FLE, but then increased to about 30% at around 40 d after FLE. The large limitation after FLE by gi was probably due to the decrease in CO2 concentration in the chloroplast caused by the increases in thickness of mesophyll cell walls and in Rubisco content per chloroplast surface area. These results clearly showed that: (1) in C. sieboldii, chloroplast development proceeded more slowly than mesophyll cell expansion and continued well after FLE, whereas in P. vulgaris these processes proceeded synchronously and were completed by FLE; (2) after FLE, photosynthesis in leaves of C. sieboldii was markedly limited by gi. From these results, it is suggested that, in the evergreen broad-leaved trees, mechanical protection of mesophyll cells has priority over the efficient CO2 transfer and quick construction of the chloroplasts. [source]

Macroscopic Anatomy of the Great Vessels and Structures Associated with the Heart of the Ringed Seal (Pusa hispida)

H. Smodlaka
Summary The ringed seal [Pusa (Phoca) hispida], as well as other seals, exhibits unique anatomical properties when compared to its terrestrial counterparts. In the ringed seal, the most conspicuous marine adaptation is the aortic bulb. This large dilatation of the ascending aorta is comparable to that found in other seal species and marine mammals. The branches of the ascending aorta (brachiocephalic trunk, left common carotid artery and left subclavian artery) are similar to those of higher primates and man. The peculiarities of the venous system are: three pulmonary veins, a pericardial venous plexus, a caval sphincter, a hepatic sinus with paired caudal vena cavae and a large extradural venous plexus. Generally, three common pulmonary veins (right, left and caudal) empty into the left atrium. The pericardial venous plexus lies deep to the mediastinal pericardial pleura (pleura pericardica) on the auricular (ventral) surface of the heart. The caval sphincter surrounds the caudal vena cava as it passes through the diaphragm. Caudal to the diaphragm, the vena cava is dilated (the hepatic sinus), and near the cranial extremity of the kidneys, it becomes biphid. The azygos vein is formed from the union of the right and left azygos veins at the level of the 5th thoracic vertebra. Cardiovascular physiological studies show some of these anatomical variations, especially of the venous system and the ascending aorta, to be modifications for diving. This investigation documents the large blood vessels associated with the heart and related structures in the ringed seal. [source]

Intraocular pressure change after temporal clear corneal phacoemulsification in normal eyes

Inci Irak-Dersu
Abstract. Purpose:, To evaluate short- and long-term intraocular pressure (IOP) changes after temporal clear corneal phacoemulsification in normal eyes. Methods:, The charts of 266 consecutive non-glaucoma patients who underwent uneventful cataract surgery were reviewed. We recorded preoperative and postoperative (1 day, 1 week, 1 month, 3 months, 6 months, 1 year and 2 years) IOP measurements as well as anatomical properties obtained using Zeiss Humphrey IOL Master (Zeiss Meditech, Dublin, California, USA). Results:, Mean IOP reduction after cataract surgery was 8.2%, 4.6%, 6.7% and 7.8% at 3 months, 6 months, 1 year and 2 years, respectively. Lens thickness was the only anatomical characteristic that correlated significantly with IOP decrease after surgery. Conclusion:, Temporal clear corneal phacoemulsification results in a decrease in postoperative IOP that persists for 2 years following surgery. [source]