Quantitative Analysis of Leaf Development in Xanthium Pensylvanicum

Abstract

Maksymowych, Roman. (Villanova U., Villanova, Pa.) Quantitative analysis of leaf development in Xanthium pensylvanicum. Amer. Jour. Bot. 46(9): 635–644. Illus. 1959.—An attempt was made to find a quantitative way of describing the development of the leaf and to correlate the developmental processes, designating precisely their sequence. The processes were presented in terms of the absolute and relative rates of leaf length, expansion of lamina in surface, increase in thickness, rates of cell division of leaf 9 and 13, and tissue differentiation of 3 portions of the lamina. All rates were estimated over the entire period of development, from initiation of a primordium to its maturity. The leaf plastochron index (L.P.I.) was used as a morphological time‐scale. The relative plastochron rates were used for the purpose of correlation of the developmental processes. Leaf 9 elongates exponentially up to 3.0 L.P.I. with an average relative rate (dlnL/dpl) of about 0.78 pl‐1, and it stops growing around 8.0 L.P.I. The lamina stops elongating about 1.5 plastochrons before the petiole. The tip of the lamina expands its surface at a constantly lower relative rate than the middle and the basal portions of the blade. The average relative rate of expansion in area (dlnA/dpl) for the whole lamina is 1.7pl‐1 during the exponential stage. Differentiation of the laminar tissues proceeds basipetally, from the tip toward the base of the leaf. The relative rate of expansion of lamina in thickness (dlnT/dpl) is 0.55 pl‐1 at 1.5 L.P.I. and after 4.0 L.P.I. all cells cease elongating in a plane perpendicular to the leaf surface. The formation of cells proceeds exponentially up to 3.0 L.P.I. and about this time cell divisions stop in all parts of the lamina. The mean relative rate of cell formation (dlnC/dpl) at the exponential phase is 1.41 pl‐1, an increase of about 31% per day. At least 27 generations of cells are involved in the process of leaf formation and the generation time was calculated to be 0.5 plastochron or 2.2 days.

Computational Method for Quantifying Growth Patterns at the Adaxial Leaf Surface in Three Dimensions

“…Moreover, the growth patterns we observed are consistent with other leaf growth analyses, which have shown a similar proximodistal gradient in growth rates in Arabidopsis (Wiese et al, 2007) as well as in other species, such as tobacco (Nicotiana tabacum; Avery, 1933;Poethig and Sussex, 1985;Walter and Schurr, 1999;Walter et al, 2003), sunflower (Helianthus annuus; Granier and Tardieu, 1998), grape (Vitis vinifera; Wolf et al, 1986), spinach (Spinacia oleracea; Saurer and Possingham, 1970), cocklebur (Xanthium pensylvanicum; Maksymowych, 1959;Erickson, 1966), ivy (Hedera helix; Wang et al, 2011), and poplar (Populus spp. ; Taylor et al, 2003).…”

“…Early efforts to measure leaf growth involved drawing ink dots on the adaxial leaf surface to delineate a grid of small rectangles whose deformations over time could be used to calculate regional growth rates (Avery, 1933;Richards and Kavanagh, 1943). Other studies since then have employed the same concept of quantifying growth at the adaxial leaf surface by tracking ink marks (Maksymowych, 1962;Saurer and Possingham, 1970;Poethig and Sussex, 1985;Granier and Tardieu, 1998;Wang et al, 2011) or vein intersections (Maksymowych, 1959;Erickson, 1966;Wolf et al, 1986;Walter and Schurr, 1999;Taylor et al, 2003;Walter et al, 2003). Recently, digital image sequence analysis tools have been developed to automatically track the displacement of identifiable features in successive images of a leaf (Schmundt et al, 1998;Ainsworth et al, 2005;Wiese et al, 2007).…”

“…This is because drawing or printing ink dots on the leaf surface (Avery, 1933;Richards and Kavanagh, 1943;Maksymowych, 1962;Poethig and Sussex, 1985;Granier and Tardieu, 1998;Wang et al, 2011) or threading or clipping weights through the leaf margins, as required for the digital image sequence analysis setup (Schmundt et al, 1998;Ainsworth et al, 2005;Wiese et al, 2007), require that the leaf be relatively large, and vascular features (Maksymowych, 1959;Erickson, 1966;Wolf et al, 1986;Walter and Schurr, 1999;Taylor et al, 2003;Walter et al, 2003) are not visible at early stages of development.…”

Winter crop growth at low temperature may hold the answer for alpine treeline formation

“…With this classical leaf census method (Maksymowych 1959;Pieters 1974;Dale and Milthorpe 1983), data for consecutive cohorts of leaves were collected for c. 50 leaves over a period of 30 d (23 November to 22 December 2006), accumulating to > 1000 individual readings (less numbers of days for the younger leaf cohorts). Knowing the vigour of each leaf cohort, it was then possible, post hoc, to select the six most vigorously growing age categories for temperature responses.…”

Expansion of Bean Leaves and its Suppression by Salinity

“…However, several recent investigations (2,14,22) indicate that it is largely the result of an increase in cell number. The purpose of the present investigation was to find out A) which process, cell enlargement or cell division, is primarily responsible for the expansion of beaan leaves, and B) how salinity limits the expansion of these leaves.…”