種子,裸子植物(wu)(wu)和(he)被子植(zhi)物(wu)(wu)特有(you)的繁殖體,它由胚(pei)珠經過傳粉(fen)受精(jing)形(xing)成。種(zhong)(zhong)子一(yi)般由種(zhong)(zhong)皮(pi)、胚(pei)和(he)胚(pei)乳3部分組成,有(you)的植(zhi)物(wu)(wu)成熟的種(zhong)(zhong)子只有(you)種(zhong)(zhong)皮(pi)和(he)胚(pei)兩部分。種(zhong)(zhong)子的形(xing)成使幼小的孢子體胚珠得到母體的(de)保(bao)護,并(bing)像(xiang)哺乳動物(wu)的(de)胎(tai)兒那樣得到充足的(de)養料。種(zhong)子還有(you)種(zhong)種(zhong)適于(yu)傳(chuan)播(bo)或抵抗不良(liang)條(tiao)件的(de)結構,為植物(wu)的(de)種(zhong)族(zu)延續(xu)創(chuang)造了良(liang)好的(de)條(tiao)件。所以(yi)(yi)在(zai)植(zhi)(zhi)物的系統發育過程(cheng)中(zhong)種(zhong)(zhong)子(zi)(zi)(zi)植(zhi)(zhi)物能(neng)夠代替蕨類植(zhi)(zhi)物取得(de)優勢地(di)位。以(yi)(yi)上(shang)為植(zhi)(zhi)物學意義(yi)種(zhong)(zhong)子(zi)(zi)(zi),而非生產上(shang)的種(zhong)(zhong)子(zi)(zi)(zi),生產上(shang)的種(zhong)(zhong)子(zi)(zi)(zi)不僅包(bao)括前面的植(zhi)(zhi)物學種(zhong)(zhong)子(zi)(zi)(zi),還包括植(zhi)物可用作繁殖的器官和人造種子。
冬季,種子大多需要儲存(cun)起來,儲存(cun)的好(hao)壞(huai)直接關系到來年的生產。因(yin)此,要做好(hao)防護(hu)措(cuo)施,讓種(zhong)子(zi)保(bao)持清潔干燥。因(yin)為種(zhong)子(zi)的含水量過高,在冬季潮濕的環境中很可能造成霉變(bian),所以在儲存前要將種(zhong)子曬干,控制(zhi)好(hao)種(zhong)子本身所含(han)(han)的水分。一般來(lai)說,禾谷(gu)類(lei)作物種(zhong)子的含(han)(han)水量為12%-13%,油料作物種(zhong)子的含(han)(han)水量為8%-9%。玉米、花生(sheng)、大(da)豆等(deng)含淀粉和油脂(zhi)較多的(de)種子(zi)(zi)更容易發生(sheng)霉變,需要(yao)(yao)特(te)別注意。在(zai)種子(zi)(zi)儲(chu)存前(qian),要(yao)(yao)將種子(zi)(zi)徹底清潔,去除(chu)作(zuo)物(wu)莖葉、雜草、砂子(zi)(zi)、土粒(li)等(deng)雜物(wu);不少作(zuo)物(wu)的(de)種子和(he)一般糧(liang)(liang)食不易(yi)區分,不注意(yi)會(hui)造成(cheng)(cheng)種、糧(liang)(liang)混(hun)雜,造成(cheng)(cheng)浪費和(he)減產,在留(liu)種早期就要分開(kai)放置(zhi)。