Wakame is a frequent visitor on the dining table in coastal areas. It can be crisp or smooth, can be used in soup or cold salad, and rattan pepper is salty or spicy.
Are you salivating just by looking at the photos? Wakame has high nutritional value, not only contains a lot of vitamins, amino acids, mannitol and minerals, but also rich in biologically active substances such as fucoxanthin, alginic acid, fucoidan and so on. Although we eat it all the time, it may be difficult to answer the following questions immediately: Is wakame equal to kelp? Does wakame have a gender? If so, which genders can it be divided into?
Kelp or wakame?
In our country, due to the high popularity of kelp, wakame has been living in the shadow of kelp. Needless to say, people in the interior are basically not familiar with wakame, and even residents of coastal cities often refer to wakame as kelp.
Now is the time to give wakame a name!
Wakame and kelp are both large edible seaweeds, but belong to different groups.
Undaria pinnatifida, commonly known as sea cabbage, belongs to the seaweeds of Phaeaceae, Laminaria, Pterophyceae, and Undaria genus. Undaria pinnatifida is relatively high temperature resistant, so it can grow well in oceans with warm currents.
Kelp, commonly known as river cabbage, belongs to the seaweeds of Phaeophyceae, Laminaria, Laminaceae, and Laminaria. Kelp generally grows on rocks on the seabed in the subtidal zone. The growth of kelp is greatly affected by light and temperature.
Wakame is an annual seaweed plant, while kelp is a perennial seaweed plant, which is the essential difference between the two.
The larvae of wakame are very similar to the larvae of kelp, but the appearance after growing up is obviously different from that of kelp.
A whole piece of wakame looks like a big broken sunflower fan. The leaves are relatively thin. There is an obvious long stalk in the middle, with obvious bulges. The color is lighter than that of kelp. The leaves have cracks and are crony-shaped, which is also very similar to Wakame, so it is called wakame.
However, due to the growth environment, kelp looks very complete, with a thick texture, long flat fronds, no long stalk in the middle, and the whole body is olive brown, which turns dark brown after drying.
A more direct way to distinguish is: the leaves of wakame are thinner than kelp, and the color is lighter and greener than kelp.
In addition to morphological differences, kelp and wakame also differ nutritionally. Both are algae and contain similar nutrients, but there is a significant difference in content: the iodine content of kelp is nearly 10 times higher than that of wakame leaves. The calcium content of wakame is 1.5 times that of kelp, and the content of magnesium and zinc is better than that of wakame.
Left: Wakame. Right: Kelp. Picture｜Scientific refutation of rumors
It should be noted that patients with thyroid disease cannot blindly eat kelp and wakame, but need to determine whether to limit iodine-rich foods under the guidance of a doctor.
Kelp and wakame are good calcium supplements. If there is no high need for iodine, wakame would be a better choice. Moreover, it is also superior in magnesium, zinc, and iron content. Even so, relying on individual foods still cannot meet the needs of the human body, and a balanced diet is required to eat healthy.
Indeed, wakame and kelp belong to the brown algae of the order kelp, and they look very similar at the seedling stage, but when they grow up, the “appearance” of wakame is far better than that of kelp.
Wakame is also named because of its shape like a woman’s crony. Artificially cultivated wakame, because of its improved traits, the leaves are smooth and bright in color, swaying in the sea, graceful and charming, very ornamental.
The leaves of wakame are soft and elastic, so it not only has a high “value”, but also tastes better than kelp. Anyone who has eaten wakame marvels at its deliciousness.
So here comes the question, when you eat wakame and feast on it, have you ever thought about the gender of the wakame you ate?
The traditional view is that the haploid gametophyte of Wakame has only two sexes, female and male, and is dioecious. Japanese scholars have found hermaphroditism in diploid gametophytes obtained from somatic cell culture, which is logical because diploid gametophytes have both U and V chromosomes.
Hermaphrodite, androgynous?
Undaria pinnata is an annual seaweed, and its life history includes two generations of large sporophytes and microscopic gametophytes. Because there are obvious differences in size and shape between the two, this life history is called heterogeneous alternation of generations.
On the reefs along the northern coast such as Qingdao, we can usually observe more obvious seedlings of wakame after the end of winter (January and February). We call this large frond a sporophyte. What we eat and grow are the sporophytes of wakame.
The normal sporophyte is diploid and is the asexual generation in the life history of wakame, that is, it has no sex and does not show sex difference or differentiation. When the sporophyte grows to the breeding season (usually after June in the north), its sporophyll will release spores that can swim, and the spores will form a haploid gametophyte after attaching to the attachment base such as reefs. Due to the small number of cells and the small size of the gametophyte in nature, it cannot be observed by the naked eye.
Ordinary gametophytes have female and male sex differentiation and are therefore sexual generations. We know that XX and XY sex chromosomes determine the sex of human female and male respectively, while the sex of haploid gametophytes of brown algae such as kelp, wakame, and water cloud is determined by U and V sex chromosomes, and those with U chromosomes are Females, males with type V chromosomes.
Therefore, the traditional view is that the haploid gametophytes of Undaria pinnata have only two sexes, female and male, and are dioecious. Japanese scholars have found hermaphroditism in diploid gametophytes obtained from somatic cell culture, which is logical because diploid gametophytes have both U and V chromosomes.
What makes the sex of wakame confusing is that researchers from the seaweed germplasm bank of the Institute of Oceanology, Chinese Academy of Sciences discovered hermaphroditism for the first time in haploid wakame gametophytes, which show male morphological characteristics in the initial vegetative growth stage , but in the stage of inducing gametogenesis, sperm sacs and oocysts can be formed at the same time, and then sperm and eggs are produced respectively.
