Lettuce. Lettuce is a fairly hardy, cool-weather vegetable that thrives when the average daily temperature is between 60 and 70Â°F. It should be planted in early spring or late summer. At high temperatures, growth is stunted, the leaves may be bitter and the seedstalk forms and elongates rapidly.ipburn is a physiological condition that causes lettuce to die back at the edges of the leaves. It results from a change in the moisture relationship between the soil and the plant. Clip off any brown leaf tissue and use the remainder of the leaf.
chromosphere. A layer of gas that lies above the photosphere of a star, such as the Sun. Thesaurus Antonyms Related Words Synonyms Legend: Switch to new thesaurus . Noun: 1. chromosphere - a gaseous layer of the sun's atmosphere (extending from the photosphere to the corona) that is visible during a total eclipse of the sun layer - a relatively thin sheetlike expanse or region lying over or under another
The atmosphereâs outer layer is called the corona (crown). In ultraviolet light, it is revealed to be full of loops of hot gas. These coronal loops may rise as high and as wide as 500,000 km (300,000 miles). The inner layer of the Sunâs atmosphere is a pinkish colour and is called the chromosphere (colour-sphere).rom Earth, observers cannot usually see the corona, or outer atmosphere of the Sun, because the photosphere (surface) is so bright. During a total eclipse, however, the moon blocks out the surface and we can see the Sunâs atmosphere.