Effect of Temperature on Seed Germination in Spinach (Spinacia oleracea)

Abstract

<jats:p>Breeding heat-tolerant spinach is an important project to meet the demand of increasing spinach production in heat conditions. Seed germination is the early stage to test, screen, and develop heat-tolerant spinach genotypes. The objective of this research was to determine temperature effect on the seed germination percentage and to select heat-tolerant spinach genotypes. A total of nine spinach genotypes were used in this research. The germination experiment was conducted using seven temperatures: 10, 15, 20, 25, 30, 32, and 35 °C under growth chambers. The temperature trials were conducted using completely randomized design (CRD) with three replicates. Spinach seed germination percentage varied among the nine spinach genotypes under the seven temperatures, indicating that genetic variation for heat tolerance existed in the nine spinach genotypes. ‘Donkey’, ‘Marabu’, and ‘Raccoon’ showed higher seed germination percentage with over 70% at 30 and 32 °C, indicating the three spinach genotypes had heat tolerance for germination. However, all spinach genotypes except ‘Ozarka II’ dropped their germination percentages sharply to less than 30%; ‘Ozarka II’ had 63% germination under 35 °C, indicating it is a good source of heat tolerance for seed germination. The higher germination percentages above 30 °C of ‘Ozarka II’, ‘Donkey’, ‘Marabu’, and ‘Raccoon’ may indicate their potential as donors of heat-tolerant traits in spinach breeding program.</jats:p>

Investigating Seed Dormancy in Pinus bungeana Zucc. ex Endl.: Understanding the Contributions of Enclosing Tissues and Temperature on Germination

“…This temperature variation is called thermos-inhibition, which is characterized by the absence of germination when the temperature is slightly above the optimum conditions [36]. Germination inhibition by high temperatures (25 • C-30 • C) has been observed in other species, such as Spinacia oleracea L. [17,18], Ornithopus pinnatus [19], and Myrsine parvifolia [20], and the seeds of these three species have also shown higher final germination at temperatures of 15 • C and 20 • C, while significantly lower germination occurred at 25 • C and 30 • C.…”

“…The failure of many seeds to germinate may not be due to the seeds needing pretreatment but may be that the seeds merely require specific temperature regimes to germinate [16]. For example, either no germination or extremely low germination was observed at 25 • C and 30 • C, while high final germination was obtained when seeds were incubated at lower temperatures of 15 • C and 20 • C for species such as Pinacia oleracea L. [17,18], Ornithopus pinnatus (Mill.) Druce [19], and Myrsine parvifolia A. DC.…”

Seed priming with seaweed extract mitigate heat stress in spinach: effect on germination, seedling growth and antioxidant capacity

“…Temperature is considered to be a critical environmental factor on seed germination because it inhibits radicle emergence and affects seedling growth (Ashraf and Foolad 2005). For spinach, the optimal temperature range between 15 and 20 °C and outside of this temperature range, germination declines gradually (Chitwood et al 2016). In this study, heat stress reduced germination of controls by 25 and 38% at 7 and 21 days after sowing, respectively.…”

“…Spinach (Spinacea oleracea) is cultivated mainly during the cool season, with optimal ranges for germination and plant growth between 7 to 24 °C and 15 to 20 °C, respectively (Chitwood et al 2016). High temperatures are common in tropical and subtropical climates and may delay seed germination or loss of vigor that lead to reduced emergence and seedling establishment (Wahid et al 2007).…”

РОСТ ЗАРОДЫША И ПРОРАСТАНИЕ ГЕТЕРОМОРФНЫХ СЕМЯН Anethum graveolens L. (Apiaceae) ПОД ДЕЙСТВИЕМ ВЫСОКОЙ ТЕМПЕРАТУРЫ

“…Тепловой стресс -один из самых значимых абиотических факторов, определяющих продуктивность многих сельскохозяйственных культур (56)(57)(58), в частности сельдерейных (59,60). Считается, что превышение оптимальной температуры для конкретного вида растений на 10-15 С вызывает цепь ответных реакций, направленных на передачу стресс-сигнала и повышение устойчивости, выражающейся в сдвиге метаболических реакций и физиологических процессов (61)(62)(63).…”