THE RELATIONSHIP BETWEEN THE THICKNESS OF DECIDUOUS LEAVES AND THEIR MAXIMUM PHOTOSYNTHETIC RATE

摘要: MCCLENDON, JOHN H. (U. Delaware, Newark.) The relationship between the thickness of deciduous leaves and their maximum photosynthetic rate. Amer. Jour. Bot. 49(4): 320-322. Illus. 1962.-Data Willstiitter Stoll (25?, saturating light C02) are used to show that it is useful plot rate per unit area as a function density (g/cm2; fresh wt) leaves. Data for 23 species were plotted together. If P rate, T total thickness, E epidermis, linear relation found using values P, such = R (T E), where about 30 (mg (hr)-1 (g F.W.)-. Using this expression, 15 represented by over 23, while very young leaves, aurea2 few others fell in range 8-16. A mean value was taken, from other data, be 3 X 10-3 g/cm2, ranged 10 40 0.2 0.8 CR2) hr'I cm-2 "normal" IF one looks research studies relating leaf anatomy, almost vain, spite wide variety types organization chlorenchyma (Haberlandt, 1914; Meyer, 1923; Stover, 1951) numerous ecological anatomy (Clements, 1904; Hayden, 1919; Weaver Clements, 1938; SteemanNielsen, 1940; Isanogle, 1944; Daubenmire, 1947; Wylie, 1951). Only study physiology sun shade (Rabinowitch, papers Pickett (1937), Kenworthy (1940), have I been able find any direct attempt correlate structure with function. However, Willstatter (1918) included 19 tables under uniform conditions, wet weight, dry chlorophyll content many species, mainly deciduous. When these data analyzed graphically, found, well known, emphasis given later authors entirely unjustified. In fact, entitled "Normale Assimilationzahlen" "Hohe Assimilationzahlen normaler Blatter" merely selections larger set continuous, unbroken values. (The assimilation number divided content.) Then if aurea or senescent evergreens omitted, weight within small (mean 18.1 [mg C02] hr-1 [g F.W.]-'; standard deviation 3.6). most often basis measurement on distribI Received publication May 10, 1961. 2 Yellow-leaved horticultural varieties. uted range. It then realized his must due variations thickness. manner bring out result reported below. While seems incredible simple concept has not expressed before, certainly failed its way into texts reference works anatomy. Neither search original literature, exception which came my attention being prepared publication. Pieters (1960) measured Acer pseudoplatanus, correlated mesophyll. presented here more extensive than different measure MATERIALS AND METHODS-The taken Willstaitter (1918: Tables 7, 16, 18, 22, 24-31, 38, 40, 41, 44, 47, 48, 49). there 73 non-duplicated sets wherein meassured at 25 C, 45,000 lux 5% CO2 (i.e., carbon dioxide). (Senescent, chlorotic etiolated included.) Typographical errors corrected comparison duplicate listings. listed Table 1; serial numbers some extent figure. Where measurements made same points figures connected lines. Several during period growth. younger did yield rates (per weight) high great majority so segregated "very young" basis. RESULTS-While recorded Willstiatter Stoll, possible calculate called terms area. should proportional actual