Why is cucumber a green joke?

The pigments in chloroplasts include chlorophyll, lutein, carotene, lutein and so on. In the semi-mature stage of cucumber, chlorophyll accounts for the largest proportion, which masks the colors of other pigments. At the mature stage of cucumber, chlorophyll is decomposed, and the proportion of yellow in chloroplast leaves is the largest, and cucumber turns yellow.

1. Why are cucumbers green?

1, cucumber is actually yellow when it is ripe, but because the taste of cucumber is poor after it is ripe, it tastes better in the semi-mature stage (when cucumber is green), so it has been picked before it is ripe. Over time, people think that cucumbers are green.

2. Cucumber is green in the semi-mature stage because the epidermis contains chloroplasts, but chloroplasts contain chlorophyll, lutein, carotene, lutein and other pigments, but chlorophyll accounts for the largest proportion, covering the colors of other pigments. In addition, chlorophyll absorbs red light and purple light and reflects green light, so cucumber is green. After ripening, chlorophyll decomposes and the proportion decreases. At this time, the proportion of lutein increased and cucumber turned yellow.

Second, what is the reason why cucumbers turn yellow?

1. After cucumber ripens, chlorophyll in chloroplast decomposes and the proportion decreases, so the proportion of lutein increases relatively, which leads to lutein masking the color of other pigments and causing cucumber to turn yellow.

2. Some varieties of cucumber are yellow when they grow, such as Jinguan No.1 and white cucumber.

3. If the green cucumber turns yellow during the growing period, it is generally because the cucumber has turned into a melon.

(1) The temperature during the growing period is too high (higher than 32℃ during the day and higher than 18℃ at night), which affects the normal photosynthesis of cucumber, enhances the respiration, makes cucumber malnourished, and leads to cucumber yellowing.

(2) Long-term rainy weather, insufficient sunlight and decreased photosynthesis of cucumber, coupled with soil water accumulation, affected root respiration and nutrient absorption of cucumber, leading to cucumber yellowing.

(3) The high planting density leads to the competition for nutrients among cucumbers, and the ventilation between cucumber vines is also poor.

(4) Harvesting in time, the cucumber near the bottom robbed the nutrients in the upper part of the cucumber, resulting in malnutrition and yellowing of the upper part of the cucumber.

(5) Problems such as low carbon dioxide concentration, insufficient water and fertilizer, high hormone concentration and diseases and insect pests in greenhouse have affected the normal growth of cucumber.