Types of iron deficiency in gardenias, what are the symptoms of iron deficiency yellowing in gardeni

It first occurs on the young leaves at the end of the branches, starting to fade green from the leaf margin, developing towards the center of the leaf, and the leaf color changes from green to yellow, gradually aggravating, or light yellow, but the leaf veins are still green; Later, the whole leaf turns yellow, then yellowish-white, white, and the edge of the leaf appears grayish-brown to brown, necrotic and dry; The top leaves of the whole plant are the most damaged, the lower leaves are normal or close to normal, and the plots with serious diseases weaken year by year, and finally die.

Prevention and control methods: 1. Horticultural control: it is necessary to use well-drained, soft and fertile acidic soil for cultivation, and acidic soil such as mountain mud can be used for potting, and the potting soil should be replaced once every 1-2 years; Organic fertilizers are used, and ferrous runic acid and zinc sulfate are mixed in the preparation of organic fertilizers.

2. Pesticide control: In the early stage of the disease, the diseased plant is irrigated with 2% 3% ferrous sulfate, or the leaves are sprayed with ferrous sulfate, or the integration of iron is used in the soil, 22 cm (6 inches) flower pot grams. The agent ** yellowing should be carried out at the beginning of the disease, otherwise the effect is poor.

It will get yellow leaf disease, the leaf greening, first occurs on the young leaves at the end of the branches, starting from the leaf edge to greening, developing towards the center of the leaf, the leaf color changes from green to yellow, gradually aggravating, the mesophyll becomes yellow or light yellow, but the leaf veins are still green; Later, the whole leaf turns yellow, then yellowish-white, white, and the edge of the leaf appears grayish-brown to brown, necrotic and dry; The top leaves of the whole plant are the most damaged, the lower leaves are normal or close to normal, and the plots with serious diseases weaken year by year, and finally die.

Symptoms] The disease is a whole-plant non-infectious disease. Symptoms are mainly manifested on young leaves and shoots. At first, the young shoots and leaves are pale yellow or white, the leaves are thin and small, and the veins are still green.

In severe cases, the veins are yellow or white, and eventually the leaves die. The axillary buds sprout, forming many small clumps of lateral branches. The internodes of the diseased branches are shortened and clustered into clusters.

When the disease is severe, the whole tree can be yellowish-white, the leaf veins are also yellowish-white, and the top of the young shoots is scorched, so that it dies. Diseased plants are susceptible to frostbite in winter.

Pathogen] Lack of soluble iron in the soil.

In some areas, due to the fact that the soil contains more carbonates, the soil is alkaline, so that the soluble iron content is low, or due to the rain, the soil has too much soluble iron leaching, or the soil with heavy soil viscosity and high groundwater level in the soil, the normal physiological activities of the roots of the plants are affected, which reduces the ability of the roots to absorb iron, and the lack of available iron in the plants affects the formation of chlorophyll and yellowing.

The cause of death is the phenomenon of leaf yellow death caused by iron deficiency.

Because gardenias originally grew in acidic soils in the south, iron existed in an oxidized state and ferrous sparrows, which were easily absorbed and utilized by plants. In the northern soil, which contains more carbonates and is neutral or alkaline, iron exists in the form of iron hydroxide, which cannot be absorbed and utilized by plants because it is insoluble in water. At the same time, iron often combines with carbonate in this soil to form iron carbonate, which is also insoluble in water.

Therefore, gardenias move to the north and often die due to iron deficiency.

Iron is not a component of chlorophyll, but it is necessary for the formation of chlorophyll. Because the synthesis of chlorophyll requires the activation of iron-containing enzymes, the synthesis of chlorophyll is blocked after iron deficiency. Iron has the property of interconversion of ** and low valence, so it is involved in the redox process of plants.

In addition, iron is a component of certain oxidase enzymes that play an important role in respiration. So once iron is deficient, these physiological processes are affected.

The symptoms of iron deficiency are first manifested in young leaves, because after iron enters the plant body, it forms more polymer compounds, which are in a fixed state and are not easy to transfer and reuse, so when iron is insufficient, the aging leaves often do not show symptoms, and only when there is extreme deficiency, the surface fiber slowly appears early.