99% of cherries are urged to grow? Experts point out that the use of swelling agent is safe.

  Photo courtesy of vision china

  Give you a heads-up

  Every summer, all kinds of seemingly eloquent "popular science" are "listed" simultaneously with big and red cherries.

  Recently, a video about the quality and safety of cherries spread on the Internet, saying that "99% of cherries on the market use swelling agents. Normal cherries can only grow to 12-mdash; The weight of 13 grams can be doubled with swelling agent. If there is no kernel in the cherry pit, the hollow one is medicated … …”

  What is the swelling agent that is often named? Is there really a miraculous effect in the rumor? What factors are related to the size of the cherry? To this end, the reporter visited experts in the agricultural field and consulted people on issues of concern.

  No food safety incidents caused by it have been found yet.

  "The swelling agent is a plant growth regulator. In the process of cherry growth, in order to improve pollination rate and fruit setting rate, cherry planted in greenhouse usually needs to use swelling agent; Cherry cultivated in the open field does not need to be used. " Wang Qiang, a researcher at the Agricultural Products Quality and Safety Risk Assessment Laboratory (Hangzhou) of the Ministry of Agriculture and Rural Affairs, told the reporter that at present, open-field cherry is the mainstream cultivation mode in China. According to this calculation, it is indeed possible to use plant growth regulators such as bulking agents in cherry market, but the utilization rate should be less than 50%.

  How do plant growth regulators play a role in the production of fruit and vegetable products?

  "Plant growth regulators have similar effects to plant hormones, which can stimulate the division and growth of plant cells. The difference is that plant growth regulators are artificially synthesized by scientists and modified to make their activities stronger than plant hormones." Xu Dong Hui, a researcher at the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Sciences, said.

  In terms of management, since 1997, according to the Regulations on Pesticide Management, plant growth regulators have been managed as pesticides.

  According to the relevant person in charge of the Ministry of Agriculture and Rural Affairs, at present, there are nearly 40 registered plant growth regulators in China. There are more than 100 kinds registered and used internationally. Approved and registered plant growth regulators should formulate technical specifications for safe use, including medication period, dosage, application method, scope of use, matters needing attention and safety interval, and clearly mark them on product labels to guide farmers to use them reasonably. In addition, a series of residue tests should be carried out for registered products, and residue limit standards and reasonable use criteria should be formulated according to data such as residue tests to ensure the quality and safety of agricultural products. Since 2015, the Ministry of Agriculture and Rural Affairs has conducted a risk assessment of plant growth regulator residues in agricultural products, and the results show that the average residue value of plant growth regulators is only 0.001— 0.034 mg/kg, the risk of dietary exposure is very low, and the product quality and safety are guaranteed.

  Experts said that in terms of safety, there have been no food safety incidents caused by plant growth regulator residues in the world so far. In China, agricultural products that have been applied with plant growth regulators are also very safe for consumers. Compared with other pesticides, although plant growth regulators are included in the management of pesticides, they are not pesticides for treating diseases, insects and weeding in the traditional sense. Their products are of low toxicity, and some of them are even listed as exempted substances without setting residue limits because they are almost nontoxic. For example, the toxicity of chlorfenuron commonly used in expanded fruits (LD50 > 4,918 mg/kg) is lower than that of salt (LD50 = 3,200 mg/kg). In addition, because the amount of plant growth regulator is small, excessive use is easy to produce adverse effects, and farmers can not use it in large quantities, so the residue of plant growth regulator is low.

  Fruit size is determined by many factors.

  Then, what factors are related to the size of cherry fruit, and can the swelling agent "double" the fruit?

  According to experts, large cherry and seedless cherry are related to variety characteristics, cultivation measures and the use of plant growth regulators.

  Xu Donghui told reporters that "Meizao" is the largest fruit among the cherry varieties at present. This variety of cherries has the characteristics of large fruit shape, full and sweet taste. Under normal circumstances, the single fruit weight of "Meizao" is 8-mdash; 12 grams, which can reach 16-mdash under special cultivation methods; Twenty grams.

  "A sweet cherry variety selected in China ‘ Red light ’ Under normal circumstances, the weight of a single fruit can reach 11-mdash; Fifteen grams. From the point of view of drug control, it has been reported in literature that treating cherry with plant growth regulator gibberellic acid can increase the weight of single fruit by about 15%— 30%, the swelling effect is limited. " Wang Qiang said.

  So, does cherry seedless mean that it has been treated with swelling agent? Wang Qiang said, this statement is too absolute. Although it is reported in the literature that cherry stones will be hollow after being treated with gibberellic acid at a certain concentration, it is not necessarily 100% seedless after being treated with gibberellic acid at a low concentration. In addition, the causes of cherry hollowness are natural abortion or other possibilities, not necessarily because of the use of gibberellic acid and other drugs.

  Xu Donghui explained that in order to improve the pollination rate and fruit setting rate of cherries, fruit farmers will apply gibberellin and other plant growth regulators at flowering stage, which may also cause seedless fruits and nuts, but this will not affect the safety of cherries.