旱季灌水对金菠萝产量、品质及糖酸积累的影响

Effect of Irrigation on Yield,Quality and Sugar and Acid Accumula-tion of‘MD-2’Pineapple in Dry Season

水分是影响果实生长发育的重要因素,水分通过影响植株生长直接或间接来调控果实品质的形成。季节性干旱严重制约菠萝植株生长发育,但旱季灌水对菠萝产量和品质的影响尚不明确。为了探明季节性干旱期菠萝产量和品质对水分输入的响应特征,以金菠萝‘MD-2’为研究对象,在监测旱季实际降雨量的基础上,设计4个增加灌水量梯度水平(W_(1)20 mm、W_(2)50 mm、W_(3)100 mm、W_(4)150 mm)的试验,并以不灌水为对照(CK 0 mm),分析测定菠萝产量、品质指标以及糖酸组分含量。结果表明,旱季增加灌水可显著增加金菠萝果实产量、平均单果重及商品果率,其中产量最高和最低的梯度水平分别是W_(4)和CK(W_(4)比CK增加了45.56%);随旱季灌水量的增加,金菠萝果实的维生素C、可溶性固形物和可滴定酸度均逐渐减小,可溶性总糖和糖酸比呈现先增大后减少的趋势,其整体表现为W_(2)>W_(1)>CK>W_(3)>W_(4),其中W_(2)的可溶性总糖和糖酸比最高为12.94%和26.95,显著大于CK,其增幅分别为87.26%、64.6%;金菠萝果实的蔗糖含量随旱季灌水量的增加呈现一元二次曲线函数增加(P<0.05),其比例由CK的38.8%提高到W_(4)的65.1%,整体表现为W_(4)>W_(3)>W_(1)>W_(2)>CK;而果糖和葡萄糖含量均随旱季灌水量的增加呈线性函数降低(P<0.01),二者比例的整体表现均为:CK>W_(2)>W_(1)>W_(3)>W_(4)。可见,旱季灌水促进金菠萝果实果糖和葡萄糖转化为蔗糖,且改变了其糖种类比例,进而改变了菠萝果实风味品质。随着旱季灌水量的增加,柠檬酸和奎宁酸含量均呈先增大后减小的一元二次函数关系(P<0.05),苹果酸含量呈极显著的线性函数增加(P<0.001),且旱季不同灌水量处理间,柠檬酸比例相对稳定均达到50%,而苹果酸比例仅在W_(4)处理时显著增大,奎宁酸比例在W_(4)处理时显著减小。综合考虑产量及果实风味品质,旱季进行灌水是非常必要的,且根据实际自然降雨量的多少,适当调整灌溉,使其总供水量保持在300 mm左右可实现雷州半岛地区菠萝果实优质高产。

Water is an important controllable factor that affects the growth and development of fruits,and the formation of fruit quality can be directly or indirectly controlled by affecting plant growth.However,the seasonal dry period severely restricts the growth and development of pineapple plants,especially the effect of irrigation in the dry season on the yield and quality of pineapples is still unclear.The aim of this study was to probe the response characteristics of pineapple yield and quality to water input during seasonal drought.In this experiment,‘MD-2’was used as the research object.Based on the monitoring of the actual rainfall in the dry season,four gradient levels(W_(1)20 mm,W_(2)50 mm,W_(3)100 mm,W_(4)150 mm)were designed to increase the irrigation volume,and the non-increasing irrigation was used as CK.And the yield,quality,sugar and acid content of pineapple were analyzed and determined.The results showed that increasing irrigation in the dry season could significantly increase‘MD-2’pineapple fruit yield,average single fruit weight and commercial fruit rate,and the highest and lowest gradient levels of pineapple yield were W_(4) and CK respectively(W_(4) was 45.56%more than CK).With the increase of irrigation in the dry season,vitamin C,the total soluble solids and titratable acidity of‘MD-2’pineapple fruit gradually decreased,and the total soluble sugar and sugar-acid ratio showed a trend of first increasing and then decreasing,the overall performance was W_(2)>W_(1)>CK>W_(3)>W_(4).The ratio of total soluble sugar to sugar and acid in W_(2) was the highest at 12.94%and 26.95,which was significantly greater than that in CK,with an increase of 87.26%and 64.6%,respectively.The sucrose content of‘MD-2’pineapple fruit increased with the increase of the irrigation amount in the dry season,showing a one-variable quadratic curve function(P<0.05),and its proportion increased from 38.8%of CK to 65.1%of W_(4),and the overall performance was W_(4)>W_(3)>W_(1)>W_(2)>CK;While the contents of fructose and glucose de-creased linearly with the increase of irrigation amount in the dry season(P<0.01),and the overall performance of the two ratios was:CK>W_(2)>W_(1)>W_(3)>W_(4).It can be seen that irrigation in the dry season promoted‘MD-2’pineapple fruit.Fructose and glucose were converted into sucrose,and the proportion of sugar types was changed,which in turn changed the flavor quality of pineapple fruit.The content of citric acid and quinic acid showed a significant first increase and then decrease with the increase of irrigation volume in a one-variable quadratic function relationship(P<0.05).The content of malic acid increased in a very significant linear function with the increase of irrigation in the dry season(P<0.001).In the dry season,the proportion of citric acid was relatively stable and reached 50%,while the proportion of malic acid only increased sig-nificantly in the treatment of W_(4),and the proportion of quinic acid decreased significantly in the treatment of W_(4).Irrigation in the dry season is very necessary for yield,fruit quality and fruit flavor quality improvement.According to the actual amount of natural rainfall,proper adjustment of irrigation to keep the total water supply at about 300 mm can achieve high-quality and high-yield pineapple fruits in the Leizhou Peninsula.