Responses of Rice Growth to Day and Night Temperature and Relative Air Humidity—Leaf Elongation and Assimilation

Abstract

Predictions of future crop growth and yield under a changing climate require a precise knowledge of plant responses to their environment. Since leaf growth increases the photosynthesizing area of the plant, it occupies a central position during the vegetative phase. Rice is cultivated in diverse ecological zones largely differing in temperature and relative air humidity (RH). To investigate the effects of temperature and RH during day and night on leaf growth, one variety (IR64) was grown in a growth chamber using 9 day/night regimes around the same mean temperature and RH, which were combinations of 3 temperature treatments (30/20 °C, 25/25 °C, 20/30 °C day/night temperature) and 3 RH treatments (40/90%, 65/65%, 90/40% day/night RH). Day/night leaf elongation rates (LER) were measured and compared to leaf gas exchange measurements and leaf area expansion on the plant level. While daytime LER was mainly temperature-dependent, nighttime LER was equally affected by temperature and RH and closely correlated with leaf area expansion at the plant level. We hypothesize that the same parameters increasing LER during the night also enhance leaf area expansion via shifts in partitioning to larger and thinner leaves. Further, base temperatures estimated from LERs varied with RH, emphasizing the need to take RH into consideration when modeling crop growth in response to temperature.

Dark respiration explains nocturnal stomatal conductance in rice regardless of drought and nutrient stress

“…For example, Wang et al (2021) detected a positive leaf‐level response of g sn , ranging from 0.02 to 0.05 mol m −2 s −1 , to a temperature increase from 19°C to 35°C in red birch without DS. Thus, to determine whether evaporative cooling is an important component of g sn behaviour or rather a passive byproduct of leaf trait coordination at higher temperature, future studies should conduct measurements over a wider range of temperatures, and possibly also conduct warming treatments, ideally at the canopy scale (Resco de Dios et al, 2018; Stuerz & Asch, 2021).…”

Leaf Blade Growth and Development in Red, Pink, and Yellow Petiole Cultivars of the Swiss Chards Grown in Floating Culture System

“…Daytime leaf elongation rate (LER) was mainly temperature-dependent. LER at night was influenced by temperature and relative humidity (Stuerz and Asch, 2021). Leaf widening revealed a strong sensitivity to plant intercepted light and weak reaction to evaporative demand.…”

Genotype x Environment x Management (GEM) Reciprocity and Crop Productivity

“…Relative humidity is an important factor which impacts rice response to temperature (Stuerz and Asch, 2021) and is likely to impact other crops. High relative humidity favours plant growth, however, the response was stronger in light compared to dark conditions (Hirai et al, 2000).…”