Nasehzadeh M, Ellis R H
School of Agriculture, Policy and Development, University of Reading, Earley Gate, PO Box 237, Reading RG6 6AR, UK.
Ann Bot. 2017 Sep 1;120(3):479-493. doi: 10.1093/aob/mcx074.
Short periods of extreme temperature may affect wheat (Triticum aestivum) seed weight, but also quality. Temporal sensitivity to extreme temperature during seed development and maturation was investigated.
Plants of 'Tybalt' grown at ambient temperature were moved to growth cabinets at 29/20°C or 34/20°C (2010), or 15/10°C or 34/20°C (2011), for successive 7-d periods from 7 DAA (days after anthesis) onwards, and also 7-65 DAA in 2011. Seed samples were harvested serially and moisture content, weight, ability to germinate, subsequent longevity in air-dry storage and bread-making quality were determined.
High temperature (34/20°C) reduced final seed weight, with greatest temporal sensitivity at 7-14 or 14-21 DAA. Several aspects of bread-making quality were also most sensitive to high temperature then, but whereas protein quality decreased protein and sulphur concentrations improved. Early exposure to high temperature provided earlier development of ability to germinate and tolerate desiccation, but had little effect on maximum germination capacity. All treatments at 15/10°C resulted in ability to germinate declining between 58 and 65 DAA. Early exposure to high temperature hastened improvement in seed storage longevity, but the subsequent decline in late maturation preceded that in the control. Long (7-65 DAA) exposure to 15/10°C disrupted the development of seed longevity, with no improvement after seed filling ended. Longevity improved during maturation drying in other treatments. Early (7-14 DAA) exposure to high temperature reduced and low temperature increased subsequent longevity at harvest maturity, whereas late (35 or 42-49 DAA) exposure to high temperature increased and low temperature reduced it.
Temporal sensitivity to extreme temperature was detected. It varied considerably amongst the contrasting seed variables investigated. Subsequent seed longevity at harvest maturity responded negatively to temperature early in development, but positively later in development and throughout maturation.
短时间的极端温度可能会影响小麦（普通小麦）的种子重量，还会影响其品质。本研究调查了种子发育和成熟过程中对极端温度的时间敏感性。
将在环境温度下生长的‘泰博特’植株，于2010年从开花后7天（DAA）起，连续7天转移至29/20°C或34/20°C的生长箱中，2011年则转移至15/10°C或34/20°C的生长箱中，2011年还设置了7 - 65 DAA的处理。连续采集种子样本，测定其含水量、重量、发芽能力、随后在风干储存中的寿命以及制面包品质。
高温（34/20°C）降低了最终种子重量，在7 - 14或14 - 21 DAA时对时间的敏感性最高。制面包品质的几个方面在此时对高温也最为敏感，但蛋白质品质下降的同时蛋白质和硫含量有所提高。早期暴露于高温下能使发芽和耐受干燥的能力更早发育，但对最大发芽能力影响不大。15/10°C的所有处理导致发芽能力在58 - 65 DAA之间下降。早期暴露于高温下加速了种子储存寿命的改善，但后期成熟过程中的下降早于对照。长时间（7 - 65 DAA）暴露于15/10°C会破坏种子寿命的发育，灌浆结束后无改善。其他处理在成熟干燥过程中寿命得到改善。早期（7 - 14 DAA）暴露于高温下会降低收获成熟时的后续寿命，低温则会增加；而后期（35或42 - 49 DAA）暴露于高温下会增加，低温则会降低。
检测到对极端温度的时间敏感性。在所研究的不同种子变量中，这种敏感性差异很大。收获成熟时的后续种子寿命在发育早期对温度呈负响应，但在发育后期和整个成熟过程中呈正响应。
