| Abstract | U radu je istražen učinak mehanički izazvanog stresa na morfološke karakteristike i vrijeme cvatnje nevena (Calendula officinalis L.), niske kadifice (Tagetes patula L.) i visoke kadifice (T. erecta L.). Tretman presadnica obavljan je jednom dnevno, povlačenjem pamučne tkanine po površini biljaka (četkanje). Tretman je započeo kada su biljke bile u fazi razvoja drugog para pravih listova kod nevena te prvog para pravih listova kod kadifica, a trajao je do pojave prvih vidljivih cvatnih pupova. Mjerenja morfoloških parametara provedena su nakon završetka tretmana i na dan početka cvatnje. Tretman četkanjem imao je statistički značajan utjecaj na visinu presadnica samo kod nevena, u kojega su tretirane presadnice nakon završetka tretmana bile 24 % niže od netretiranih. U vrijeme početka cvatnje, visina biljaka se niti kod jedne istražene vrste nije statistički značajno razlikovala između tretiranih i netretiranih presadnica. Kod niske kadifice tretman nije utjecao niti na ostale mjerene parametre. Međutim, tretirane presadnice visoke kadifice imale su nešto deblje stabljike, veći broj postranih grana i veći broj listova nego netretirane biljke, dok su tretirane presadnice nevena bile uspravnijeg rasta nego netretirane presadnice. Tretman četkanjem je u presadnica nevena i visoke kadifice također rezultirao većim brojem broj cvatnih pupova. Iako je u tretiranih presadnica visoke kadifice došlo je do malog pomaka u vremenu početka cvatnje, tretman niti kod jedne istražene vrste nije utjecao na datum cvatnje 50 % biljaka. Rezultati istraživanja pokazuju da tretman četkanjem može poboljšati neke komercijalno važne karakteristike presadnica nevena i visoke kadifice. Međutim, u obje su se vrste prilikom četkanja u nekih biljaka oštetili listovi, a oštećenjima je osobito bio podložan neven. Stoga je kod ovih vrsta potrebno istražiti učinke metoda izlaganja mehaničkom stresu koje ne oštećuju ili u manjoj mjeri oštećuju biljke. |
| Abstract (english) | In this work, the effect of mechanically-induced stress on plant morphological characteristics and flowering time was studied in common marigold (Calendula officinalis L.), French marigold (Tagetes patula L.) and African marigold (T. erecta L.). Transplants were subjected to daily brushing treatments with a cotton cloth. Brushing started when plants were developing second pair of true leaves, in common marigold, and first pair of true leaves, in French marigold and African marigold. The treatments lasted until first inflorescence buds became visible. Morphological parameters were measured after treatment cessation and at the time of anthesis. Brushing had statistically significant effect on plant height only in common marigold, in which treated plants were 24 % lower than untreated ones, after treatment cessation. However, in none of the investigated species the treatment led to statistically significant differences in plant height, at the time of anthesis. In French marigold, the treatment also did not influence other measured parameters. However, in African marigold were stem diameter, number of lateral branches and number of leaves statistically significantly higher in treated plants, while, in common marigold, the treatment resulted in more erect stems. In addition, treated common marigold and African marigold had a greater number of flower buds, at the time of anthesis. Although treatment in African marigold slightly shifted time of anthesis, in none of the investigated species number of days to 50 % flowering was affected by brushing. The results of this study show that mechanical stress can improve some of the commercially important characteristics of common marigold and African marigold. However, brushing also caused damage on some leaves, especially in common marigold. Further research is thus needed to find methods of exposure to mechanical stress that does not cause damage or cause less damage to plants. |
