植物茎部粗细的决定因素

植物图片 2019-03-26 13:49

植物茎部粗细的决定因素

放眼我们周围的世界，看看挺拔而直指天穹的秀丽白杨、婀娜多姿的垂柳、迎着微风频频低头的小草，让人有一种直抒胸臆的温柔感。大树之所以挺拔，小草之所以迎风不倒，是由于它们都有坚强的脊梁——茎。

植物的茎大都生长在地面上，负载着繁茂的枝叶、花、果实，还要抵挡风雨侵袭，因此，植物的茎具有强大的支持、抗御的能力。因此，茎的外型，大多数呈圆柱形。但有些植物的茎却呈三角形，如莎草；方柱形，如蚕豆、薄荷；扁平柱形，如昙花、仙人掌，所以貌看植物的茎单一，实际上也是变化多端的。

当春天来临，万物复苏，杨柳返青之时，你不妨截取一段粗细适合的杨树或柳树的茎，会很轻易地剥下树皮，你会发现剥下的树皮的内面是一薄层白色的柔韧的东西，这部分叫做树木的韧皮部。剥下树皮剩下的部分，坚硬呈白色叫木质部，占茎的大部分。你这时用手指摸摸韧皮部的内面或木质部的外面，你会发现，手指有一种滑溜溜的湿润的感觉，这是形成层，夹在韧皮部与木质部之间。形成层才是茎的粗细的决定者，由于这一层的细胞具有特别旺盛的分裂能力，少部分向外分裂的细胞形成新的韧皮部，主要是向内分裂的细胞形成新的木质部，新形成的韧皮部细胞，加在原有的韧皮部里面，新形成的木质部细胞加在原先形成的木质部外面。从茎的横切面上看，形成层就好像是一个大皮圈，木质部面积不断加大，皮圈也不断扩大外移，这样树木的直径也就随着加粗了。所以茎的粗细是由神奇的形成层决定的。那么草本植物的茎却如此之细，原因又何在呢？

原来草本植物的茎中没有像树木那样的绕茎一圈的形成层，它们茎内的形成层是一束一束的，像星星一样分散在茎当中。如果你看过玉米的茎的横切面，会看到在茎中分散着一个一个的小黄点，那便是形成层所在部位，这样的茎的加粗能力就很有限了。此外，草本植物生活周期很短，大多数在一个生长季节内就结束寿命，往往在它的茎还没有来得及加粗时，生命就结束了，所以它们的茎都很细。（来源：植物百科）

专题：
相关文章
植物新文章
  1. 秋季改善土壤肥力的6个小方法

    秋季改善土壤肥力的6个小方法

    花卉的生长离不开肥料的供给，但是土壤的肥沃程度，在一定程度上对花卉的生长也起着十分重要的作用。养花总是离不开施肥，所以一些改善土壤的肥力的小方法是很有必要的。那么，来看看这些改善土壤的小方法都有哪些吧！...

    118 2021-10-19 00:31

  2. 碰碰香怎么养殖

    碰碰香怎么养殖

    养碰碰香需要用疏松和排水性良好的土壤，不要浇太多的水，使之保持半干半湿的状态最好。要将它放在阳光充足的地方，在冬季要做好保暖措施，温度要保证在5-10℃。繁殖方法可以用扦插繁殖，极易成活，另外还要加强病虫害的...

    111 2021-10-25 08:18

  3. 铁海棠叶子变黄怎么办

    铁海棠叶子变黄怎么办

    铁海棠叶子变黄的原因有很多。如果是积水导致的，需要及时排水，并换土重栽；如果是空气不畅导致的，需要加强通风；如果是温度太低导致的，需要及时保温；如果是肥料太浓导致的，需要用水稀释，或者更换盆土并清洗根部...

    180 2021-03-21 15:09

  4. 杜鹃红山茶北方怎么养

    杜鹃红山茶北方怎么养

    花土选择：花土要疏松，酸碱值在5.5-6.5最好，土壤不适合就要重新购买。浇水频次：通常是每周浇水5-7次，应见干就浇，空气湿度应在60%左右。施肥换土：每个月都要给它施一次肥，并且每年还要换一次盆土。修剪工作：要修剪掉...

    154 2021-08-23 17:57

  5. 扦插繁殖怎样选择插条

    扦插繁殖怎样选择插条

    应选择长势旺盛、枝叶粗壮、生长充实、腋芽饱满且无病虫害的新生枝条来采插条。一般来说，母株中上部的枝条比下部的好；1~2年生的枝条比多年生的好；枝条中部的比上部和下部的好。 不带叶的插条，只能依赖插穗本身供给营...

    218 2020-04-09 10:05

  6. 杏花哪个季节开放

    杏花哪个季节开放

    杏花是春季开放的，也就是在4-5月份，一朵花的花期能持续7天左右，一棵树一般能持续大约20天左右。花苞是纯红色的，花期慢慢变淡，盛花期白色带有红晕，凋谢会变成纯白色。要是出现不开花的情况，一般是授粉不成功，可观...

    176 2021-08-13 11:14

联系我们
  • 网站内容来自于互联网，仅作参考！！！
  • QQ：81888188
  • 微信：
  • 邮箱：
依希植物网

为您提供专业的室内植物养护知识和花卉花语，室内盆栽植物养殖和盆景制作方法，常见花卉植物养护方法和注意事项。

Copyright WWW.TVIX.CN
植物 | 植物标签 | 鄂ICP备2020020415号-4

返回顶部小火箭
Weibo Article 1 Weibo Article 2 Weibo Article 3 Weibo Article 4 Weibo Article 5 Weibo Article 6 Weibo Article 7 Weibo Article 8 Weibo Article 9 Weibo Article 10 Weibo Article 11 Weibo Article 12 Weibo Article 13 Weibo Article 14 Weibo Article 15 Weibo Article 16 Weibo Article 17 Weibo Article 18 Weibo Article 19 Weibo Article 20 Weibo Article 21 Weibo Article 22 Weibo Article 23 Weibo Article 24 Weibo Article 25 Weibo Article 26 Weibo Article 27 Weibo Article 28 Weibo Article 29 Weibo Article 30 Weibo Article 31 Weibo Article 32 Weibo Article 33 Weibo Article 34 Weibo Article 35 Weibo Article 36 Weibo Article 37 Weibo Article 38 Weibo Article 39 Weibo Article 40 Weibo Article 41 Weibo Article 42 Weibo Article 43 Weibo Article 44 Weibo Article 45 Weibo Article 46 Weibo Article 47 Weibo Article 48 Weibo Article 49 Weibo Article 50 Weibo Article 51 Weibo Article 52 Weibo Article 53 Weibo Article 54 Weibo Article 55 Weibo Article 56 Weibo Article 57 Weibo Article 58 Weibo Article 59 Weibo Article 60 Weibo Article 61 Weibo Article 62 Weibo Article 63 Weibo Article 64 Weibo Article 65 Weibo Article 66 Weibo Article 67 Weibo Article 68 Weibo Article 69 Weibo Article 70 Weibo Article 71 Weibo Article 72 Weibo Article 73 Weibo Article 74 Weibo Article 75 Weibo Article 76 Weibo Article 77 Weibo Article 78 Weibo Article 79 Weibo Article 80 Weibo Article 81 Weibo Article 82 Weibo Article 83 Weibo Article 84 Weibo Article 85 Weibo Article 86 Weibo Article 87 Weibo Article 88 Weibo Article 89 Weibo Article 90 Weibo Article 91 Weibo Article 92 Weibo Article 93 Weibo Article 94 Weibo Article 95 Weibo Article 96 Weibo Article 97 Weibo Article 98 Weibo Article 99 Weibo Article 100 Weibo Article 101 Weibo Article 102 Weibo Article 103 Weibo Article 104 Weibo Article 105 Weibo Article 106 Weibo Article 107 Weibo Article 108 Weibo Article 109 Weibo Article 110 Weibo Article 111 Weibo Article 112 Weibo Article 113 Weibo Article 114 Weibo Article 115 Weibo Article 116 Weibo Article 117 Weibo Article 118 Weibo Article 119 Weibo Article 120 Weibo Article 121 Weibo Article 122 Weibo Article 123 Weibo Article 124 Weibo Article 125 Weibo Article 126 Weibo Article 127 Weibo Article 128 Weibo Article 129 Weibo Article 130 Weibo Article 131 Weibo Article 132 Weibo Article 133 Weibo Article 134 Weibo Article 135 Weibo Article 136 Weibo Article 137 Weibo Article 138 Weibo Article 139 Weibo Article 140 Weibo Article 141 Weibo Article 142 Weibo Article 143 Weibo Article 144 Weibo Article 145 Weibo Article 146 Weibo Article 147 Weibo Article 148 Weibo Article 149 Weibo Article 150 Weibo Article 151 Weibo Article 152 Weibo Article 153 Weibo Article 154 Weibo Article 155 Weibo Article 156 Weibo Article 157 Weibo Article 158 Weibo Article 159 Weibo Article 160 Weibo Article 161 Weibo Article 162 Weibo Article 163 Weibo Article 164 Weibo Article 165 Weibo Article 166 Weibo Article 167 Weibo Article 168 Weibo Article 169 Weibo Article 170 Weibo Article 171 Weibo Article 172 Weibo Article 173 Weibo Article 174 Weibo Article 175 Weibo Article 176 Weibo Article 177 Weibo Article 178 Weibo Article 179 Weibo Article 180 Weibo Article 181 Weibo Article 182 Weibo Article 183 Weibo Article 184 Weibo Article 185 Weibo Article 186 Weibo Article 187 Weibo Article 188 Weibo Article 189 Weibo Article 190 Weibo Article 191 Weibo Article 192 Weibo Article 193 Weibo Article 194 Weibo Article 195 Weibo Article 196 Weibo Article 197 Weibo Article 198 Weibo Article 199 Weibo Article 200 Weibo Article 201 Weibo Article 202 Weibo Article 203 Weibo Article 204 Weibo Article 205 Weibo Article 206 Weibo Article 207 Weibo Article 208 Weibo Article 209 Weibo Article 210 Weibo Article 211 Weibo Article 212 Weibo Article 213 Weibo Article 214 Weibo Article 215 Weibo Article 216 Weibo Article 217 Weibo Article 218 Weibo Article 219 Weibo Article 220 Weibo Article 221 Weibo Article 222 Weibo Article 223 Weibo Article 224 Weibo Article 225 Weibo Article 226 Weibo Article 227 Weibo Article 228 Weibo Article 229 Weibo Article 230 Weibo Article 231 Weibo Article 232 Weibo Article 233 Weibo Article 234 Weibo Article 235 Weibo Article 236 Weibo Article 237 Weibo Article 238 Weibo Article 239 Weibo Article 240 Weibo Article 241 Weibo Article 242 Weibo Article 243 Weibo Article 244 Weibo Article 245 Weibo Article 246 Weibo Article 247 Weibo Article 248 Weibo Article 249 Weibo Article 250 Weibo Article 251 Weibo Article 252 Weibo Article 253 Weibo Article 254 Weibo Article 255 Weibo Article 256 Weibo Article 257 Weibo Article 258 Weibo Article 259 Weibo Article 260 Weibo Article 261 Weibo Article 262 Weibo Article 263 Weibo Article 264 Weibo Article 265 Weibo Article 266 Weibo Article 267 Weibo Article 268 Weibo Article 269 Weibo Article 270 Weibo Article 271 Weibo Article 272 Weibo Article 273 Weibo Article 274 Weibo Article 275 Weibo Article 276 Weibo Article 277 Weibo Article 278 Weibo Article 279 Weibo Article 280 Weibo Article 281 Weibo Article 282 Weibo Article 283 Weibo Article 284 Weibo Article 285 Weibo Article 286 Weibo Article 287 Weibo Article 288 Weibo Article 289 Weibo Article 290 Weibo Article 291 Weibo Article 292 Weibo Article 293 Weibo Article 294 Weibo Article 295 Weibo Article 296 Weibo Article 297 Weibo Article 298 Weibo Article 299 Weibo Article 300 Weibo Article 301 Weibo Article 302 Weibo Article 303 Weibo Article 304 Weibo Article 305 Weibo Article 306 Weibo Article 307 Weibo Article 308 Weibo Article 309 Weibo Article 310 Weibo Article 311 Weibo Article 312 Weibo Article 313 Weibo Article 314 Weibo Article 315 Weibo Article 316 Weibo Article 317 Weibo Article 318 Weibo Article 319 Weibo Article 320 Weibo Article 321 Weibo Article 322 Weibo Article 323 Weibo Article 324 Weibo Article 325 Weibo Article 326 Weibo Article 327 Weibo Article 328 Weibo Article 329 Weibo Article 330 Weibo Article 331 Weibo Article 332 Weibo Article 333 Weibo Article 334 Weibo Article 335 Weibo Article 336 Weibo Article 337 Weibo Article 338 Weibo Article 339 Weibo Article 340 Weibo Article 341 Weibo Article 342 Weibo Article 343 Weibo Article 344 Weibo Article 345 Weibo Article 346 Weibo Article 347 Weibo Article 348 Weibo Article 349 Weibo Article 350 Weibo Article 351 Weibo Article 352 Weibo Article 353 Weibo Article 354 Weibo Article 355 Weibo Article 356 Weibo Article 357 Weibo Article 358 Weibo Article 359 Weibo Article 360 Weibo Article 361 Weibo Article 362 Weibo Article 363 Weibo Article 364 Weibo Article 365 Weibo Article 366 Weibo Article 367 Weibo Article 368 Weibo Article 369 Weibo Article 370 Weibo Article 371 Weibo Article 372 Weibo Article 373 Weibo Article 374 Weibo Article 375 Weibo Article 376 Weibo Article 377 Weibo Article 378 Weibo Article 379 Weibo Article 380 Weibo Article 381 Weibo Article 382 Weibo Article 383 Weibo Article 384 Weibo Article 385 Weibo Article 386 Weibo Article 387 Weibo Article 388 Weibo Article 389 Weibo Article 390 Weibo Article 391 Weibo Article 392 Weibo Article 393 Weibo Article 394 Weibo Article 395 Weibo Article 396 Weibo Article 397 Weibo Article 398 Weibo Article 399 Weibo Article 400 Weibo Article 401 Weibo Article 402 Weibo Article 403 Weibo Article 404 Weibo Article 405 Weibo Article 406 Weibo Article 407 Weibo Article 408 Weibo Article 409 Weibo Article 410 Weibo Article 411 Weibo Article 412 Weibo Article 413 Weibo Article 414 Weibo Article 415 Weibo Article 416 Weibo Article 417 Weibo Article 418 Weibo Article 419 Weibo Article 420 Weibo Article 421 Weibo Article 422 Weibo Article 423 Weibo Article 424 Weibo Article 425 Weibo Article 426 Weibo Article 427 Weibo Article 428 Weibo Article 429 Weibo Article 430 Weibo Article 431 Weibo Article 432 Weibo Article 433 Weibo Article 434 Weibo Article 435 Weibo Article 436 Weibo Article 437 Weibo Article 438 Weibo Article 439 Weibo Article 440 Weibo Article 441 Weibo Article 442 Weibo Article 443 Weibo Article 444 Weibo Article 445 Weibo Article 446 Weibo Article 447 Weibo Article 448 Weibo Article 449 Weibo Article 450 Weibo Article 451 Weibo Article 452 Weibo Article 453 Weibo Article 454 Weibo Article 455 Weibo Article 456 Weibo Article 457 Weibo Article 458 Weibo Article 459 Weibo Article 460 Weibo Article 461 Weibo Article 462 Weibo Article 463 Weibo Article 464 Weibo Article 465 Weibo Article 466 Weibo Article 467 Weibo Article 468 Weibo Article 469 Weibo Article 470 Weibo Article 471 Weibo Article 472 Weibo Article 473 Weibo Article 474 Weibo Article 475 Weibo Article 476 Weibo Article 477 Weibo Article 478 Weibo Article 479 Weibo Article 480 Weibo Article 481 Weibo Article 482 Weibo Article 483 Weibo Article 484 Weibo Article 485 Weibo Article 486 Weibo Article 487 Weibo Article 488 Weibo Article 489 Weibo Article 490 Weibo Article 491 Weibo Article 492 Weibo Article 493 Weibo Article 494 Weibo Article 495 Weibo Article 496 Weibo Article 497 Weibo Article 498 Weibo Article 499 Weibo Article 500 Weibo Article 501 Weibo Article 502 Weibo Article 503 Weibo Article 504 Weibo Article 505 Weibo Article 506 Weibo Article 507 Weibo Article 508 Weibo Article 509 Weibo Article 510 Weibo Article 511 Weibo Article 512 Weibo Article 513 Weibo Article 514 Weibo Article 515 Weibo Article 516 Weibo Article 517 Weibo Article 518 Weibo Article 519 Weibo Article 520 Weibo Article 521 Weibo Article 522 Weibo Article 523 Weibo Article 524 Weibo Article 525 Weibo Article 526 Weibo Article 527 Weibo Article 528 Weibo Article 529 Weibo Article 530 Weibo Article 531 Weibo Article 532 Weibo Article 533 Weibo Article 534 Weibo Article 535 Weibo Article 536 Weibo Article 537 Weibo Article 538 Weibo Article 539 Weibo Article 540 Weibo Article 541 Weibo Article 542 Weibo Article 543 Weibo Article 544 Weibo Article 545 Weibo Article 546 Weibo Article 547 Weibo Article 548 Weibo Article 549 Weibo Article 550 Weibo Article 551 Weibo Article 552 Weibo Article 553 Weibo Article 554 Weibo Article 555 Weibo Article 556 Weibo Article 557 Weibo Article 558 Weibo Article 559 Weibo Article 560 Weibo Article 561 Weibo Article 562 Weibo Article 563 Weibo Article 564 Weibo Article 565 Weibo Article 566 Weibo Article 567 Weibo Article 568 Weibo Article 569 Weibo Article 570 Weibo Article 571 Weibo Article 572 Weibo Article 573 Weibo Article 574 Weibo Article 575 Weibo Article 576 Weibo Article 577 Weibo Article 578 Weibo Article 579 Weibo Article 580 Weibo Article 581 Weibo Article 582 Weibo Article 583 Weibo Article 584 Weibo Article 585 Weibo Article 586 Weibo Article 587 Weibo Article 588 Weibo Article 589 Weibo Article 590 Weibo Article 591 Weibo Article 592 Weibo Article 593 Weibo Article 594 Weibo Article 595 Weibo Article 596 Weibo Article 597 Weibo Article 598 Weibo Article 599 Weibo Article 600 Weibo Article 601 Weibo Article 602 Weibo Article 603 Weibo Article 604 Weibo Article 605 Weibo Article 606 Weibo Article 607 Weibo Article 608 Weibo Article 609 Weibo Article 610 Weibo Article 611 Weibo Article 612 Weibo Article 613 Weibo Article 614 Weibo Article 615 Weibo Article 616 Weibo Article 617 Weibo Article 618 Weibo Article 619 Weibo Article 620 Weibo Article 621 Weibo Article 622 Weibo Article 623 Weibo Article 624 Weibo Article 625 Weibo Article 626 Weibo Article 627 Weibo Article 628 Weibo Article 629 Weibo Article 630 Weibo Article 631 Weibo Article 632 Weibo Article 633 Weibo Article 634 Weibo Article 635 Weibo Article 636 Weibo Article 637 Weibo Article 638 Weibo Article 639 Weibo Article 640 Weibo Article 641 Weibo Article 642 Weibo Article 643 Weibo Article 644 Weibo Article 645 Weibo Article 646 Weibo Article 647 Weibo Article 648 Weibo Article 649 Weibo Article 650 Weibo Article 651 Weibo Article 652 Weibo Article 653 Weibo Article 654 Weibo Article 655 Weibo Article 656 Weibo Article 657 Weibo Article 658 Weibo Article 659 Weibo Article 660 Weibo Article 661 Weibo Article 662 Weibo Article 663 Weibo Article 664 Weibo Article 665 Weibo Article 666 Weibo Article 667 Weibo Article 668 Weibo Article 669 Weibo Article 670 Weibo Article 671 Weibo Article 672 Weibo Article 673 Weibo Article 674 Weibo Article 675 Weibo Article 676 Weibo Article 677 Weibo Article 678 Weibo Article 679 Weibo Article 680 Weibo Article 681 Weibo Article 682 Weibo Article 683 Weibo Article 684 Weibo Article 685 Weibo Article 686 Weibo Article 687 Weibo Article 688 Weibo Article 689 Weibo Article 690 Weibo Article 691 Weibo Article 692 Weibo Article 693 Weibo Article 694 Weibo Article 695 Weibo Article 696 Weibo Article 697 Weibo Article 698 Weibo Article 699 Weibo Article 700 Weibo Article 701 Weibo Article 702 Weibo Article 703 Weibo Article 704 Weibo Article 705 Weibo Article 706 Weibo Article 707 Weibo Article 708 Weibo Article 709 Weibo Article 710 Weibo Article 711 Weibo Article 712 Weibo Article 713 Weibo Article 714 Weibo Article 715 Weibo Article 716 Weibo Article 717 Weibo Article 718 Weibo Article 719 Weibo Article 720 Weibo Article 721 Weibo Article 722 Weibo Article 723 Weibo Article 724 Weibo Article 725 Weibo Article 726