NaCl胁迫对不同倍性西瓜幼苗Na^+、K^+和Ca^(2+)质量分数的影响

Effects of NaCl Stress on Mass Fractions of Na^+,K^+ and Ca(2+) in Different Ploidy Watermelon Seedlings

以黄枚西瓜同源二倍体(2x)、三倍体(3x)、四倍体(4x)为材料,分别用100、200、300、400mmol/L NaCl处理西瓜幼苗,鉴定不同浓度NaCl对不同倍性西瓜幼苗的伤害程度,采用微波消解-火焰原子吸收分光光度法测定NaCl胁迫8d后不同倍性西瓜幼苗叶片中的Na+、K+和Ca2+质量分数。结果表明,NaCl胁迫8d以后,随着NaCl浓度的增加,西瓜幼苗受害程度也随着加深,相同NaCl浓度下,不同倍性西瓜幼苗受伤害程度为2x>3x>4x;4x幼苗叶片中的Na+质量分数高于2x和3x。高NaCl浓度下,西瓜幼苗叶片内的K+质量分数为4x>2x>3x,Ca2+的质量分数为4x>2x。NaCl胁迫后,耐NaCl胁迫能力表现为多倍体强于2x,4x的西瓜幼苗相对于2x具有较高的Na+、K+和Ca2+质量分数,与其表现的受伤害程度一致,3x的西瓜幼苗的受伤害程度与K+质量分数相关性最大,耐NaCl胁迫能力介于4x和2x间。2x的西瓜幼苗叶片受伤害程度与Na+、K+和Ca2+质量分数及K+/Na+比值、Na+/Ca2+比值的相关性较多倍体低。

The NaC1 solutions with concentration of 100, 200, 300, 400 mmol/L were used to treat different homologous ploidy seedlings of Huangmei watermelon. The effects of plant growing charac- teristics and the mass fractions of ions were investigated in different ploidy watermelon under NaC1 stress after 8 days. The mass fractions of Na＋ , K＋ and Ca2＋ were determined by flame atomic absorp- tion spectrometry. The results showed that the suffer index of watermelon seedlings increased with the increase of the salt concentration. The damage degree in different ploidy seedlings was 2x〉3x〉4x at the same level NaC1 concentration. The mass fraction of Na＋ was higher in 4x than it in 2x and 3x, the order of the mass fraction of K＋ was 4x〉2x〉3x under high salt concentration, 2x got more seri- ous damage than 4x because it was more sensitive to Ca2＋. The studies suggested that the 4x water- melon seedlings had higher mass fractions of Na＋ , K＋ and Ca2＋ and stronger salt tolerance than 2x af- ter NaC1 treatment. This situation was consistent with the plant growth characteristics. Correlation coefficient of the mass fraction of K＋ and damage degree of 3x watermelon seedlings is the biggest in the three ions. The capacity of NaCI stress resistance in 3x was between 2x and 4x. The correlation coefficient of the mass fractions of ions and damage degree of 2x watermelon seedlings is smaller than that in 3x and 4x.