在历年水稻育秧过程中,我们发现有时田间发生少量秧苗第二叶的叶尖卷卡于卷枯的第一叶内,随第二叶的伸长,其叶身弓起,形成“钩尖苗”。由于“钩尖苗”的第二叶长期弓曲而不能展开,就使其生育延迟甚至不能出生新叶而死亡,导致群内生长不整齐或发生死苗现象。 据观察,“钩尖苗”一般发生于迟播秧田和室内育秧的一叶一心期。由稻叶生长规律可知,第二叶的叶叶与第一叶的叶鞘同步伸长。由于第二叶的叶片长度远大于第一叶的叶鞘长度,故在正常温度条件下,第一叶叶枕即将抽出(叶片临近全展)时,第二叶的叶尖已伸入仍处于心叶状态的第一叶的叶片内部(简称为叶片生长的“超前”现象),在较高的温度条件下育秧时,这种“超前”现象更为明 During the rice seedling growth in the past years, we found that sometimes a small amount of leaf tip of the second leaf of the young seedling was stuck in the first leaf of the withered leaf. With the elongation of the second leaf, the leaf body bowed to form a “ ”. As the second leaf of “Hook Jianmiao” can not be deployed due to the long bow of the second leaf, it can delay the birth or even die of new leaf, resulting in irregular growth or dead seedling in the herd. It is observed that “Hook spider Miao” generally occurs in late-sowing seedling and indoor leaf-growing one leaf period. The law of growth of rice leaves shows that the leaf of the second leaf is elongated synchronously with the leaf sheath of the first leaf. As the blade length of the second leaf is much longer than the sheath length of the first leaf, when the first leaf blade is about to be withdrawn at normal temperature This leaves the leaf inside the leaf state (referred to as the “leading” phenomenon of leaf growth), this “advanced” phenomenon is more obvious when the seedlings are raised under higher temperature conditions