長期熱逆境對番茄胚發育影響之研究

Abstract

熱逆境是番茄生殖生長的主要不利因素。隨著全球暖化加劇，番茄在生殖生長期間處於長期熱逆境（chronic heat stress）的情況愈發普遍。然而，長期熱逆境對番茄果實與種子發育的影響仍未被充分探討。先前研究指出，在授粉後第5天接受高溫處理的果實(HS05組)，成熟後果皮變薄且種子顯著得縮小，而在授粉後第15天(HS15組)處於長期熱逆境的果實，成熟果實和種子未被觀察到有形態上的改變。本研究分析長期熱逆境在West Virginia 106番茄果實發育早期（授粉後第5天）與晚期（授粉後第15天）對胚發育的影響。HS05組種子幾乎不發芽，然而種子發芽率在HS15組僅有輕微下降。比較長期熱逆境與正常環境溫度下的授粉後12天種子，觀察到HS05種子的胚發育階段遲滯且子葉形狀異常。由於種子透明化處理不確實，HS15組的胚胎發育情形尚不明確。本研究結果顯示，長期熱逆境在果實早期發育階段會干擾胚胎發生過程，這可能是導致種子發芽率降低的主要原因。未來仍需進一步釐清長期熱逆境對處於發育後期階段胚胎的影響。

Heat stress is a major constraint on tomato reproduction. Chronic heat stress is becoming increasingly prevalent due to global warming. The impact of heat stress on early fruit and seed development remains underexplored. In this study, we investigated the effects of chronic heat stress during early (5 DPA) and later (15 DPA) stages of fruit development in tomato. In a previous study, tomato fruits at 5 DPA exposed to chronic heat stress developed thinner pericarps and smaller seeds, while no visible morphological changes were observed in HS15 fruits. In the present study, seed germination was significantly reduced in HS05 and only slightly affected in HS15. Detailed embryogenesis in the tomato cultivar West Virginia 106 was observed under control conditions. We revealed developmental lag and abnormal cotyledon emergence in HS05 seeds at 12 DPA. Embryogenesis under HS15 remained unclear due to inadequate seed clearing. These findings indicate that chronic heat stress during early fruit development disrupts embryogenesis, likely contributing to reduced seed viability. Further research is needed to determine the effects of heat stress on later stages of embryogenesis.