Uniformity of Impatiens Plug Seedling Growth in Controlled Environments

Abstract

<jats:p>Uniformity of growth response of impatiens <jats:italic>(Impatiems wallerana</jats:italic> Hook. f.) plug seedlings was examined in four identical growth rooms. Differences among growth rooms for dry weight, height, and leaf area of 10- to 24-day-old seedlings were generally not significant. During six experiments over 6 months, an individual growth room was maintained under contant baseline environmental conditions. Differences in growth response over time appear to be related to nutrition and irradiance levels. For three experiments with nearly identical irradiance, temperature, and nutrition levels, dry weight and height growth differences over time were only rarely significant. These results illustrate that rather unsophisticated growth rooms can provide consistent growth response over time among experimental units.</jats:p>

Temperature Effects on Growth of Impatiens Plug Seedlings in Controlled Environments

“…Details on the design and operation of the growth rooms have been reported (Dreesen and Langhans, 1991). A brief synopsis of important features of the seedling production system are reiterated below.…”

“…), compressed, and refilled. One lot of mix was used in all experiments (about one bag per experiment); appreciable differences in the nutrient charge were found between bags (Dreesen and Langhans, 1991).…”

“…Details on the seedling sampling procedure are reported in Dreesen and Langhans (1991). The mean shoot dry weight for each tray was determined from the total dry weight divided by the number of seedlings sampled (sample size varied with age, e.g., from 55 to 75 seedlings comprised a sample on Day 10).…”

“…Earlier studies investigated whether intrinsic differences between growth rooms would result in significantly different growth response when nearly identical baseline environmental condi-ions were imposed (Dreesen and Langhans, 1991). In addition, one growth room in each of seven experiments was maintained at the baseline conditions to track seedling growth response over time.…”

“…The present study was part of a comprehensive investigation of the growth of bedding plant plug seedlings produced in CEGR. The results of initial studies to determine the uniformity of seedling growth response among growth rooms and over time have been reported (Dreesen and Langhans, 1991). The goal of the present study was to determine the growth response of 10-to 25-day-old impatiens seedlings to various temperature treatments under CEGR conditions (i.e., continuous lighting).…”