Growth characteristics of spring barley and selected weeds. II. Effect of temperature and irradiance in growth chambers

Abstract

Summary As a part of a broader study, two experiments were carried out in growth chambers with three day/night temperature regimes (10/7, 20/14 and 30/21^C) studying growth characteristics of individual seedlings over a four‐week period. Experiment 1 was performed with spring barley (Hordeum vulgare L.), Galeopsis tetrahit L., and Viola Arvensis Murray. Experiment 2, with three irradiance levels at 20/14^C, and one irradiance level at the other temperatures, was performed with spring barley, V. arvensis, Chenopodium album L., Brassica rapa L. sspoleifera (DC.) Metzger, and Stellaria media (L.) Vill. Leaf area, dry weight, relative growth rate, net assimilation rate, and net photosynthetic rate generally showed an optimum at 20/14^C. Increasing irradiance resulted in a decreased specific leaf area. Expressed as fraction of shoot dry weight, green leaves decreased and stems, flowers, and yellow leaves increased with increased time, irradiance, and temperature. At all temperatures, barley, B. rapa and G. tetrahit had the largest dry weights, but at 20/14^C. C album and S. media and at 30/21^C C. album also had large values. Differences in dry weight between species correlated more to morphological features than to assimilation rate.

ExploringChenopodium albumadaptive traits in response to light and temperature stresses

“…At both harvests, leaf area production increased in Low PPFD compared with that in High PPFD plants (Table 3). Considering seed set alone, high temperature increased leaf area production [high = 1.21 cm 2 (mol m −2 ) −1 of incident PPFD, low = 0.83 cm 2 (mol m −2 ) −1 of incident PPFD; P = 0.0427], which concurs with a previous study (Semb, 1996b). Between low PPFD treatments at seed set, leaf area was also reduced by low R/FR (see Table 3), consistent with the literature (Holmes & Smith, 1977; Child et al.…”

“…The height of the plants increased because of low R/FR and low PPFD up to inflorescence initiation, but by seed set, plants were insensitive to R/FR and height was influenced by an interaction of low PPFD and temperature ( P = 0.0264). At inflorescence initiation, plant height was not influenced by temperature ( P = 0.8369), a finding which was contrary to that of Semb (1996b). When comparing the above‐ to below‐canopy light treatments, height by inflorescence initiation increased because of low R/FR and low PPFD (High PPFD High R/FR = 3.8 cm, Low PPFD High R/FR = 7.0 cm, Low PPFD Low R/FR = 9.7 cm; P = 0.0022).…”

Effect of Herbicides on Field Violet (Viola arvensis) in Direct-Seeded Spring Wheat

“…Application of POST herbicides generally had no effect on crop yields (Table 4). The lack of a yield response to herbicide application was likely an indication of the weakly competitive nature of field violet (Semb 1996a(Semb , 1996b(Semb , 1996c and the variable effects of biotic (Poaceae family weeds and barley) and abiotic (drought) stresses on crop production.…”