Cardinal temperatures for planting-emergence phase in gladiolus

Abstract

The objective of this study was to determine the cardinal temperatures for the planting-emergence phase of gladiolus. A controlled environment experiment was performed in a growth chamber in the Universidade Federal do Pampa - Campus Itaqui, using the completely randomized experimental design with 12 temperature treatments (5°C, 7°C, 10°C, 13°C, 16°C, 18°C, 20°C, 22°C, 25°C, 30°C, 33°C, 35°C) and ten replicates. Corms of the cultivar ‘Amsterdam’ were planted at a depth of 10cm in 1.7dm3 pots. Every day the date of emergence of the gladiolus plants was observed. Then for each treatment, the emergence rate was calculated as the inverse of the duration of the budding phase, and estimated data were achieved employing the non-linear model of simulation. The lower base and upper base temperatures were identified at the non-emergence temperatures. To estimate the optimum temperature, the root of mean square error was used. Between 22 and 25ºC the planting-emergence phase was reported to be completed in a shorter time span, although the smaller root mean square error was achieved at 22.5ºC. The cardinal temperatures of the planting-emergence phase of gladiolus, lower base, optimum and upper base temperature were 5°C, 22.5°C and 35°C, respectively.

Duração do ciclo e danos por altas e baixas temperaturas em gladíolo em função da época de plantio

“…One possible explanation for this results is that during the VE stage, development is less dependent on the variation of above ground environmental conditions, mainly air temperature, because its development occurs below ground where daily temperature variation is lower than in air temperature and, therefore, the time interval for the occurrence of this stage becomes less variable between the different planting dates than when compared to the reproductive stages of the plant, when the plant organs (leaves, stem, and florets) are directly exposed to air temperature and solar radiation. Muttoni et al (2017) when studying the influence of air temperature on the emergence of gladiolus corms, determined the basal temperature for this phase is 5 ºC. Observing Table 1, in neither of the planting dates the minimum air temperature average was below 5 ºC, which, therefore, justifies the lower variation of the values found in the VE stage between the planting dates tested.…”

Cardinal temperatures and thermal requirements for the initial development of two Brazilian native species

“…As to the maximum temperature, the estimated values were 36.6ºC for C. myrianthum, and 46.4ºC for B. orellana, which are above the absolute maximum temperature observed during the experimental period (35.7ºC). However, the estimated maximum temperature is expected to be above the maximum air temperature, since this baseline conceptually represents the maximum temperature limit at which the plant would have its metabolic processes inhibited (Freitas et al, 2017;Muttoni et al, 2017).…”

“…The effect of temperature, expressed in degree-days, is determined by the thermal time from which the daily cumulative thermal availability for the species can be computed within certain limits, called the cardinal temperatures (Muttoni et al, 2017). The cardinal temperatures are defined as follows: base temperature, which is considered the temperature below which metabolic processes are reduced, and development is null or diminished; optimum temperature, which is considered the temperature in which the maximum development occurs; maximum temperature, is that above which respiration is greater than photosynthesis, and development is null or diminished (Lisboa et al, 2012;Monteiro et al, 2014;Freitas et al, 2017).…”

“…Besides, plants are subjected to different air temperature conditions, as they can be planted in the different sowing dates or in the same sowing date, but in sites with distinct air temperature conditions (Luz et al, 2012;Souza & Martins, 2014). In some climatic conditions, such as subtropical climate, the convention is to use controlled temperature environments (Muttoni et al, 2017); however, this process is onerous and difficult to put into practice with forest species (Freitas et al, 2017).…”

“…Studies on cardinal temperatures are frequently carried out for annual and biannual cultures due to agricultural interest (Lucas et al, 2012;Luz et al, 2012;Gonçalves et al, 2015;Muttoni et al, 2017;Schmidt et al, 2018), but are practically nonexistent for perennial cultures (Souza & Martins, 2014;Freitas et al, 2017), mainly for tree species native to Brazil. Information on the capacity of a species to adapt to a wide range of environments is of great interest to producers and researchers, since knowledge of cardinal temperatures and thermal requirements values are important for developing and refining optimization strategies to manage and improve both production and its quality, as well as to integrate species that are more adapted to the climactic conditions of cultivation Freitas et al, 2017;Schmidt et al, 2018).…”