Melaleuca alternifolia, also known as Tea Tree, is a plant that faces challenges due to the intense sunlight and high temperatures in southern China. This is especially true during the summer months. The seedling stage of this plant is crucial. Too much or too little light can harm its growth. So, scientists decided to test different levels of shade to see what works best.

They tried four different shade levels on the seedlings. These levels were no shade, 35-45% shade, 45-50% shade, and 60-70% shade. After 35 days, they checked how the seedlings were doing. The results were clear. The seedlings that got 45-50% shade grew the best.

These seedlings had more chlorophyll, which helps with photosynthesis. They also had less malondialdehyde, a sign of stress. The activity of certain enzymes that fight stress, like SOD, POD, and CAT, went down. This means the seedlings were less stressed. The levels of some plant hormones, like ABA and GA3, went down. But others, like IAA, SA, and CTK, went up. This shows that the seedlings were growing well.

The leaves of these seedlings also had some changes. The lower epidermis and palisade tissue were thinner. But there were more spongy tissue cells, and the leaves were thicker overall. This suggests that the seedlings were adapting well to the shade.

So, if you're growing Melaleuca alternifolia seedlings in southern China, it's best to give them 45-50% shade. This will help them grow strong and healthy. This study gives us new ideas about how these seedlings adapt to different light levels. It also gives us a guide for growing and caring for them in the future.

Shade Secrets: How Light Affects Young Tea Tree Growth

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