鈣與磷對番茄果實尻腐病與鈣運移相關基因表現之影響

Abstract

鈣與磷為植物生長發育所需必要元素，鈣具有穩定細胞膜與細胞壁結構之功用，亦是重要次級傳訊者；磷調控多項生理、生化反應，並且是細胞膜構成之重要元素。番茄 (Solanum lycopersicum L.) 為世界重要經濟作物。在世界各地番茄生產區曾因缺鈣生理障害- 尻腐病 (blossom-end rot, BER) 的發生，導致嚴重經濟損失。導致尻腐病發生的因素繁多，如鈣肥吸收不足、細胞內鈣離子的分布不均等。sCAX1 (small cation exchanger 1) 為鈣氫離子反向轉運蛋白 (Ca2 + / H+ antiporter)，近年來研究顯示當植株大量表現sCAX1，使得鈣離子被運送至液胞貯藏，降低胞質外 (apoplastic) 鈣離子濃度，導致尻腐病的發生。本試驗以肥液滴灌方式給予植株不同濃度之鈣肥及磷肥，探討其對尻腐病發生率與鈣運移相關基因表現之影響。試驗結果顯示在‘金剛二號’，高鈣處理與低鈣處理對授粉後15天未熟期青果尻腐病發生率與嚴重度無顯著影響，但在此時期高鈣處理已降低多數鈣運移相關基因表現量；高鈣處理顯著降低‘金剛二號’授粉後45天綠熟期青果尻腐病發生率與嚴重度，且降低鈣運移相關基因表現量。其他品種不論在授粉後15或45天，鈣處理皆不顯著影響其尻腐病發生率與嚴重度，但於授粉後45天綠熟期青果，高鈣處理降低多數鈣運移相關基因表現量。相較於低磷處理，高磷處理降低‘種苗亞蔬15號’之紅熟期果實尻腐病發生率與嚴重度，也降低ATPase 4、ATPase 7、ATPase 8表現量；‘美惠’與‘CLN2460L’因為尻腐病發生率低，不易看出高磷處理對尻腐病發生率與嚴重度之效果，但高磷處理同樣降低其ATPase 4、ATPase 7表現量。上述結果顯示高鈣與高磷處理可降低‘金剛二號’與‘種苗亞蔬15號’尻腐病發生率與嚴重度，且其原因可能與降低鈣運移相關基因表現量有關。

Calcium (Ca) and phosphorus (P) are essential elements for plant growth and development. Calcium functions in maintaining structures of cell membrane and cell wall, and also serves as an important second messenger. Phosphorus is involved in the regulation of several physiological and biochemical processes, and is also an important component of cell membrane. Tomato (Solanum lycopersicum L.) is an important economic crop worldwide. Blossom-end rot (BER), a Ca related physiological disorder, had led to serious financial loss in tomato commercial production areas around the world. A lot of factors may lead to occurrence of BER, such as insufficient uptake of calcium, unbalanced partition of Ca within the cell, etc. Recent studies showed that when the transgenic plant overexpressed sCAX1 (small cation exchanger 1, a Ca2 + / H+ antiporter), more Ca2+ transport into vacuole, lower apoplastic Ca concentration and thus occurrence of BER were observed. By studying the effects of applying different concentrations of calcium and phosphate fertilizers to plants with trickle fertigation, this research intended to explore the effects of Ca and P on BER incidence and Ca transport-related genes expression. The results showed that in ‘King Kong 2’ immature-green stage fruits (15 days after pollination, 15 DAP), BER incidence and severity were not altered by high and low Ca concentration treatments, whereas high Ca concentration treatment reduced expression levels of most Ca transport-related genes. In ‘King Kong 2’ mature-green stage fruits (45 DAP), high Ca concentration treatment significantly reduced BER incidence and severity, and reduced expression levels of most Ca transport-related genes. BER incidence and severity of 15 DAP and 45 DAP fruit of other cultivars were not significantly altered by Ca treatment, whereas high Ca concentration treatment reduced expression levels of most Ca transport-related genes. In comparison to low P concentration treatment, high P concentration treatment reduced BER incidence and severity of ‘Taiwan Seed ASVEG #15’ red stage fruits as well as expression levels of ATPase 4, ATPase 7 and ATPase 8. BER incidence was low in ‘Mei Huei’ and ‘CLN2460L’, so that the effect of high P concentration treatment on BER incidence and severity could not be easily observed, while high P concentration treatment reduced expression levels of ATPase 4 and ATPase 7. Above results indicated that both high Ca and high P concentration treatments reduced BER incidence and severity of ‘King Kong 2’ and ‘Taiwan Seed ASVEG #15’, probably due to reduced expressions of Ca transport-related genes.