Seasonal changes in nitrogen fractions of Pachysandra terminalis, a forest evergreen chamaephyte

Abstract

Seasonal changes in several forms of nitrogen were investigated in the evergreen chamaephyte Pachysandra terminalis Sieb. et Zucc. growing in temperate evergreen coniferous forest. After plants sprouted new shoots, nitrogen accumulated largely as proteins in the leaves from summer to late autumn and, additionally, during a short spring period in the following year. Proteins accumulated in the overwintered leaves decreased markedly in summer, indicating that they were used for new shoot growth. A similar change was found in Fraction 1 protein. This is consistent with the seasonal changes in photosynthetic capacity and carboxylation efficiency observed in previous studies. The allocation of nitrogen to Fraction 1 protein increased in the spring, presumably to utilize better the relatively high light intensity at the forest floor before leaf expansion of the understory deciduous plants. In contrast to protein nitrogen, soluble nitrogen was present largely in stems and rhizomes. Aspargine was the major component of the amino acid pool in all organs throughout the year, especially in stems in summer. Since asparagine has the highest N:C ratio (2N:4C), an amino acid pool dominated by asparagine is economic in the use of carbon and advantageous for the carbon‐limited environment of the forest understory.

Invasion of broad‐leaf tree species into a larch plantation: seasonal light environment, photosynthesis and nitrogen allocation

“…3). A similar tendency has been reported in Pachysandra terminalis, which is a woody evergreen shrub in deciduous forests (Yoshie et al 1990). P. terminalis allocates more nitrogen to Rubisco than to other proteins during the leafless period of the overstory, so as to utilize incident PPFD.…”

“…The phenological traits of leaves of deciduous broad‐leaved trees are closely correlated with photosynthetic activity (Koike 1988, 1990, Koike et al 2001). In deciduous forests, plants growing in the understory efficiently utilize the incident light, with unique leaf adaptations over both time and location (Küppers 1989, Yoshie et al 1990, Küppers and Schneider 1993, Lei and Koike 1998a, b).…”

Storage ability of overwintering leaves and rhizomes in a semi‐evergreen fern, Dryopteris crassirhizoma (Dryopteridaceae)

“…Dryopteris crassirhizoma showed a unique pattern in nitrogen dynamics. Although leaf nitrogen content in evergreen species tends to increase in autumn for winter storage (Chapin 1980; Chapin & Kedrowski 1983; Yoshie et al . 1990), nitrogen content in the living pinnae of D. crassirhizoma sharply decreased in autumn.…”

Vegetative phenology of alpine plants at Tateyama Murodo-daira in central Japan

“…Defoliation of overwintered leaves before bud break has been shown to cause a reduction in annual shoot growth in several species (Reader 1978;Jonasson 1995;Eckstein et al 1998). The dry weight per unit leaf area in overwintered leaves decreases markedly during the period of new shoot growth in a cool-temperate species (Yoshie et al 1990). Early completion of shoot growth in summergreen trees and shrubs compared with the evergreens has been reported in a central Himalayan oak forest (Dhaila et al 1995).…”