缺水逆境對芥藍生理特性之影響

Effects of drought stress on physiological properties of Chinese kale

許珮芬(Pei-Fen Hsu)

指導教授 ： 蔡秀隆

國立屏東科技大學/農學院/農園生產系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00297

摘要

芥藍(Brassica oleracea var. alboglabra)在亞洲是廣泛地作為菜餚的十字花科蔬菜，一年四季皆可栽培。芥藍為淺根性作物，容易失水，缺水直接影響其產量與品質，而全球氣候變化越來越極端，乾旱造成的農業損失已成為人類須加以正視之課題。本研究目的為探討缺水逆境對芥藍產量與生理之影響。試驗材料為蕙津(V1)、圓葉白花(V2)、永春(V3)及翠津(V4)，缺水處理(DS)為斷水直到土壤水分低於50%田間容水量，且植株出現萎凋為止；對照組(CK)則為80%以上。於四品種中，選取葉綠素(SPAD值)與鮮(乾)重差異最大的兩個品種，進一步比較其葉片相對含水量、光合作用、細胞膜滲漏率以及脯胺酸含量等生理特徵之差異性，並分析氧自由基吸收能力。
結果顯示，葉部SPAD值以翠津最大，蕙津最小；斷水最後一天，缺水處理之SPAD值皆顯著大於對照組，且上位葉增加幅度顯著大於下位葉；採收期，蕙津、圓葉白花、永春及翠津之缺水處理鮮(乾)重相較於對照組分別減少38.09% (41.05%)、27.65% (29.91%)、29.56% (33.70%)及30.90% (33.15%)，故選取蕙津與圓葉白花進行缺水試驗之生理與抗氧化能力比較。斷水最後一天，缺水處理之相對含水量與光合作用皆顯著低於對照組；而電解質滲漏率、脯胺酸含量及氧自由基吸收能力則顯著高於對照組。蕙津與圓葉白花之生理與抗氧化能力於上位葉皆無顯著差異；於下位葉，光合作用雖無顯著差異，但缺水處理下，蕙津降低程度較圓葉白花大，此外，脯胺酸含量顯著低於圓葉白花。採收期，下位葉SPAD值於對照組，蕙津與圓葉白花無顯著差異；於缺水處理，蕙津顯著低於圓葉白花。另外，除了光合作用於缺水處理蕙津顯著高於其它處理組合外，其餘生理特徵於各處理間皆無顯著差異。
缺水逆境下，芥藍產量明顯減少，生理也受其影響。脯胺酸於缺水逆境下可以減少光合系統的傷害，以及恢復給水後提供能量，幫助植株恢復生理功能；而葉片衰老也與光合能力下降密切相關。故推測，蕙津與圓葉白花產量之差異與下位葉之脯胺酸累積、光合作用能力以及葉綠素降低，即葉片衰老黃化情形有關。另外，乾旱逆境下，葉子生理表現有時間與葉位上的差異。在未來的試驗，可以透過評估植株不同葉位的變化，來了解植株逆境生理之情形。

關鍵字

缺水逆境 ； 芥藍 ； SPAD值 ； 光合作用 ； 脯胺酸

並列摘要

Chinese kale (Brassica oleracea var. alboglabra) is a vegetable from the Brassicacea family and is widely consumed in Asian cuisine. It can be plant for all year round. Chinese kale is shallow rooted plant, prompt to water lose which would influence its yield and quality. Because of the global climate change, the effects of drought on agricultural losses have become an important issue. In this study, we will discuss how water deficit affects the yield and physiological properties of Chinese kale. Four white flower varieties Chinese kale, Veg-Gin (V1), Full White (V2), New Veg-Gin (V3), and Green Delicacy (V4) were used. The drought stress (DS) caused by water deficit was below 50% field capacity and also plant was wilting, on the other hand, the control one (CK) was higher 80% field capacity. According to the results of chlorophyll (SPAD value) and biomass, two varieties were chosen to study in more detail; the physiological properties including relative water content (RWC), photosynthesis, electrolyte leakage (EL), and proline content. Also, oxygen radical absorbance capacity (ORAC) was analysed.
It was found that there was higher SPAD value in Green Delicacy and lower in Veg-Gin. At drought stage, SPAD value of DS was significantly higher than CK; furthermore, SPAD value of upper leaf increased more than lower leaf. At harvest stage, fresh (dry) weight of Veg-Gin, Full White, New Veg-Gin, and Green Delicacy of DS compared to CK were decreased individually 38.09% (41.05%), 27.65% (29.91%), 29.56% (33.70%), and 30.90% (33.15%). Thus, Veg-Gin and Full White were chosen to study the physiological properties and ORAC under drought stress. At drought stage, RWC and photosynthesis of DS compared to CK were significantly decreased; on the contrary, EL, proline content, and ORAC were significantly increased. All of the physiological properties were no significant difference between Veg-Gin and Full White at upper leaf; however, at lower leaf, photosynthesis was no significant difference between Veg-Gin and Full White, but in Veg-Gin of DS decreased more than Full White of DS; moreover, proline content in Veg-Gin of DS was significant lower than Full White of DS. At harvest stage, at lower leaf, SPAD value of CK was no significant difference between Veg-Gin and Full White; however, of DS, Veg-Gin was significant lower than in Full White. All of the physiological properties were no significant difference between all treatment except that photosynthesis in Veg-Gin of DS was significantly higher than others.
The effects of drought stress on physiological properties in Chinese kale were evident, and drought stress made biomass lose. Proline can reduce photosynthetic system damage under water stress, and provide energy after rehydrate; Leaf senescence correlates closely with photosynthesis decline. Thus, in this study, we surmise that the different yield loss between Veg-Gin and Full White after drought stress may be related to the proline accumulation, photosynthesis abilities, and chlorophyll reducing namely leaf-yellowing at lower leaf in plant. The effect of drought stress on Chinese kale leaves showed spatio-temporal heterogeneity. Therefore, we can have further leaf-position experiment to understand the whole physiological properties of plant in the future.

並列關鍵字

Drought stress ； Brassica oleracea var. alboglabra ； SPAD value ； photosynthesis ； proline

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